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The natural history, ecology, and epidemiology of Ophidiomyces ophiodiicola and its potential impact on free-ranging snake populations
Abstract
Ophidiomyces ophiodiicola, the causative agent of snake fungal disease, is a serious emerging fungal pathogen of North American-endemic and captive snakes. We provide a detailed literature review, introduce new ecological and biological information and consider aspects of O. ophiodiicola that need further investigation. The current biological evidence suggests that this fungus can persist as an environmental saprobe in soil, as well as colonizing living hosts. Not unlike other emerging fungal pathogens, many fundamental questions such as the origin of O. ophiodiicola, mode of transmission, environmental influences, and effective treatment options still need to be investigated.
... Since the first documented observation of SFD, Ophidiomyces ophidiicola has been identified as the causative agent through phylogenetic analysis and experimental infection of snakes [17,22]. O. ophidiicola exhibits a wide array of metabolic activity (lipases, gelatinases, keratinases, etc.), has the ability to grow on the dead tissue of several taxa, and uses a variety of substrates [23]. Additionally, Ophidiomyces can grow under a wide range of temperature (7˚C to 35˚C), pH (5)(6)(7)(8)(9)(10)(11), and moisture conditions [23]. ...
... O. ophidiicola exhibits a wide array of metabolic activity (lipases, gelatinases, keratinases, etc.), has the ability to grow on the dead tissue of several taxa, and uses a variety of substrates [23]. Additionally, Ophidiomyces can grow under a wide range of temperature (7˚C to 35˚C), pH (5)(6)(7)(8)(9)(10)(11), and moisture conditions [23]. This evidence has led to the hypothesis that it can live as a saprotroph in the environment. ...
... Covariates of occupancy in a sample were hypothesized to influence presence. Soil pH, organic matter (organic) and soil moisture (moisture) all have known effects on fungal and microbial ecology within soils [23,[36][37][38]. Soil temperature (Soil t) is another influentinal factor to consider when looking at microbial presence in soils. ...
Emerging pathogenic fungi have become a topic of conservation concern due to declines observed in several host taxa. One emerging fungal pathogen, Ophidiomyces ophidiicola, is well documented as the causative agent of ophidiomycosis, otherwise known as snake fungal disease (SFD). O. ophidiicola has been found to cause disease in a variety of snake species across the United States, including the eastern massasauga (Sistrurus catenatus), a federally threatened rattlesnake species. Most work to date has involved detecting O. ophidiicola for diagnosis of infection through direct sampling of snakes, and attempts to detect O. ophidiicola in the abiotic environment to better understand its distribution, seasonality, and habitat associations are lacking. We collected topsoil and groundwater samples from four macrohabitat types across multiple seasons in northern Michigan at a site where Ophidiomyces infection has been confirmed in eastern massasauga. Using a quantitative PCR (qPCR) assay developed for O. ophidiicola, we detected Ophidiomyces DNA in topsoil but observed minimal to no detection in groundwater samples. Detection frequency did not differ between habitats, but samples grouped seasonally showed higher detection during mid-summer. We found no relationships of detection with hypothesized environmental correlates such as soil pH, temperature, or moisture content. Furthermore, the distribution of Ophidiomyces positive samples across the site was not linked to estimated space use of massasaugas. Our data suggests that season has some effect on the presence of Ophidiomyces. Differences in presence between habitats may exist but are likely more dependent on the time of sampling and currently uninvestigated soil or biotic parameters. These findings build on our understanding of Ophidiomyces ecology and epidemiology to help inform where and when snakes may be exposed to the fungus in the environment.
... Ophidiomycosis, caused by the ascomycete fungus Ophidiomyces ophidiicola, is a widespread disease affecting snakes in North America and Eurasia that typically manifests as dermatitis with necrotic lesions, but symptoms vary among species (Allender et al. 2015b;Ladner et al. 2022). Ophidiomycosis is believed to spread via direct contact with infected individuals or contaminated soil, or vertically from mother to offspring, especially in live-bearing species Stengle et al. 2019;Campbell et al. 2021). ...
... Unfortunately, previous ophidiomycosis work has been limited to O. ophidiicola challenge experiments in the laboratory or populationlevel, rather than individual-level, descriptions of disease prevalence in wild animals. As a consequence, and because snakes are notoriously enigmatic and difficult to sample (Steen 2010), we need more information about O. ophidiicola infection dynamics and ophidiomycosis impacts in wild populations to effectively inform conservation efforts (Allender et al. 2015b). ...
... There might be several explanations for such variability. First, transmission may occur sporadically as snakes move through the environment, utilize communal sites, and interact with one another (Allender et al. 2015b;Campbell et al. 2021). Copperheads are highly gregarious at hibernacula and gestation sites (Christensen et al. 2022), potentially increasing transmission risk. ...
Pathogens not only cause mortality but also impose nonlethal fitness consequences. Snakes experience trade-offs associated with behaviors that combat disease but divert time and energy away from other critical activities. The impacts of such behaviors on fitness remain poorly understood, raising concerns amid the emergence of novel herpetofaunal diseases. Ophidiomycosis, caused by the ascomycete fungus Ophidiomyces ophidiicola, impacts free-ranging snakes across North America and has been implicated in declines of several imperiled populations. Although previous ophidiomycosis research has primarily focused on disease-related mortality, few studies have evaluated nonlethal impacts on snake fitness. To address this knowledge gap, we investigated the effects of apparent ophidiomycosis on the behavior, habitat use, and movement of snakes in central New Jersey, USA, from 2020 to 2021. Our focal species was the eastern copperhead (Agkistrodon contortrix), a state species of special concern with limited representation in the ophidiomycosis literature. Although we did not observe mortality in our study population, we found that copperheads with apparent ophidiomycosis (8/31 individuals) displayed significantly different thermoregulatory behaviors than snakes without ophidiomycosis. Specifically, individuals with apparent ophidiomycosis favored areas with less canopy cover, less rock cover, and more coarse woody debris. Our findings suggest that snakes with apparent ophidiomycosis select habitats conducive to initiating behavior-mediated fever, potentially facilitating recovery.
... The fungal pathogen Ophidiomyces ophidiicola, that causes snake fungal disease (SFD, also called ophidiomycosis), has been documented in over 42 species of wild snakes across three continents [27][28][29][30][31][32][33][34] , and is considered a threat to the conservation of snake populations 35,36 . Clinical signs of disease caused by O. ophidiicola can range from mild skin lesions, from which snakes can recover, to severe infections that impair movement, disrupt feeding behavior, and can ultimately lead to death 28,36,37 . ...
... The fungal pathogen Ophidiomyces ophidiicola, that causes snake fungal disease (SFD, also called ophidiomycosis), has been documented in over 42 species of wild snakes across three continents [27][28][29][30][31][32][33][34] , and is considered a threat to the conservation of snake populations 35,36 . Clinical signs of disease caused by O. ophidiicola can range from mild skin lesions, from which snakes can recover, to severe infections that impair movement, disrupt feeding behavior, and can ultimately lead to death 28,36,37 . Snake fungal disease is known to affect a wide range of snake species, irrespective of their ecological traits and phylogenetic relationships 29 . ...
... Snake fungal disease has garnered much attention over the last few decades, as this disease has been recognized as a potential threat to snake populations 28,36 . Despite this, few studies have systematically examined geographic differences in prevalence and disease severity and the contribution of host pathogen interactions. ...
Infectious diseases are influenced by interactions between host and pathogen, and the number of infected hosts is rarely homogenous across the landscape. Areas with elevated pathogen prevalence can maintain a high force of infection and may indicate areas with disease impacts on host populations. However, isolating the ecological processes that result in increases in infection prevalence and intensity remains a challenge. Here we elucidate the contribution of pathogen clade and host species in disease hotspots caused by Ophidiomyces ophidiicola, the pathogen responsible for snake fungal disease, in 21 species of snakes infected with multiple pathogen strains across 10 countries in Europe. We found isolated areas of disease hotspots in a landscape where infections were otherwise low. O. ophidiicola clade had important effects on transmission, and areas with multiple pathogen clades had higher host infection prevalence. Snake species further influenced infection, with most positive detections coming from species within the Natrix genus. Our results suggest that both host and pathogen identity are essential components contributing to increased pathogen prevalence.
... Reports are continuing to appear concerning the symptoms, diagnostics, prevalence, mortality and effects on populations, as well as new hosts and new locations [4,22,25]. The apparent range extensions may be real or indicative of increased awareness and efforts, or both. ...
... Fungal diseases have the potential to cause sublethal effects, lethal effects, and to devastate populations of vertebrates [1][2][3]. Even though habitat fragmentation and loss, illegal exploitation ("poaching") and climate change may devastate snake populations, fungal diseases may also play a significant role in local snake declines and possibly local extinctions [4][5][6]. Ophidiomycosis, also called snake fungal disease (SFD), is caused by Ophidiomyces ophidiicola [7]. SFD can cause severe disease and mortality in some snake species [4,[8][9][10]. ...
... Ophidiomycosis, also called snake fungal disease (SFD), is caused by Ophidiomyces ophidiicola [7]. SFD can cause severe disease and mortality in some snake species [4,[8][9][10]. Laboratory experiments have demonstrated that SFD is caused by O. ophidiicola by showing that snakes experimentally infected with the fungus develop skin lesions (=sores) and other abnormalities observed in the wild and that the fungus was isolated from infected snakes in the wild [11][12][13]. ...
Ophidiomyces ophidiicola, the fungus causing snake fungal disease (SFD), has been identified in northern pine snakes (Pituophis melanoleucus) in New Jersey. In this paper, we (1) review the positivity rate of SFD on different locations on snakes’ bodies, (2) determine the relationship between the sores and quantitative polymerase chain reaction (qPCR) positivity rates, and (3) explore the relationship between the investigators’ clinical evaluation of the severity of sores, their evaluation of the likelihood of the sores being positive, and the qPCR positivity of SFD for the sores. Swabbing the sores was more effective at determining whether the snakes tested positive for O. ophidiicola than ventrum swabbing alone. The perception of the severity of the sores did not relate to qPCR positivity for O. ophidiicola. We suggest that the assessment of the rate of SFD among snakes in the wild needs to include the sampling of snakes with no clinical signs, as well as those with sores, and the swabbing of all the sores collectively. Clear terminology for sores, the identification of clinical signs of SFD, and distinguishing the rates of O. ophidiicola by PCR testing should be adopted. Overall, the pine snakes exhibited a higher rate of sores and positivity of O. ophidiicola swabs by PCR testing compared to the other snakes.
... An emerging disease affecting wild and captive snakes, ophidiomycosis, also known as Snake Fungal Disease (SFD) is caused by the ascomycete fungus Ophidiomyces ophidiicola (Oo). There is a growing concern over its potential impact to free-ranging snake populations in North America and Europe, and captive snake collections around the world (Allender et al., 2015b;Lorch et al., 2015). An overview of specific findings and circumstantial evidences concerning the decline associated with Oo are summarized in Allender et al., 2015b;Lorch et al., 2016;Di Nicola et al., 2022. ...
... There is a growing concern over its potential impact to free-ranging snake populations in North America and Europe, and captive snake collections around the world (Allender et al., 2015b;Lorch et al., 2015). An overview of specific findings and circumstantial evidences concerning the decline associated with Oo are summarized in Allender et al., 2015b;Lorch et al., 2016;Di Nicola et al., 2022. The classic clinical sign associated with SFD is a variable extensive to multifocal dermatitis (see examples in supplementary fig. ...
... Five out of 159 snakes without lesions were tested positive for Oo consistently with previous studies (Hileman et al., 2018;Chandler et al., 2019;Lizarraga et al., 2023), possibly suggesting that: (1) the snakes were in early stages of infection; (2) direct contact between infected and not infected snakes might have allowed a superficial load of Oo to be transferred to the uninfected individual and to be sufficient to give a positivity by PCR; (3) the efficiency of clearing the superficial infection by shedding was not complete and left residual Oo; (4) snakes would have been in contact of Oo that was present in the environment but would have not developed clinical signs yet (Allender et al., 2015b); and (5) Oo growth might have been inhibited by soil microbial communities (Campbell et al., 2021). All these hypotheses are not necessarily mutually exclusive. ...
The discovery of the fungal pathogen Ophidiomyces ophidiicola ( Oo ), the aetiologic agent of Snake Fungal Disease (SFD), has raised a growing interest in the North American and European scientific communities, in particular toward conservation. This pathogen is known or suspected to be associated with the declines of some snake populations in North America and was detected later in Europe. Its ecology, distribution and phylogeography still remain largely unknown. In this study, we collected skin swabs from 271 free-ranging snakes in Switzerland across 8 different species and 13 sites. The overall pathogen prevalence was at least 28% with sequences consistent with both the European and the North American lineages (respectively Clade I and II) of Oo . Semi-aquatic snakes were more likely to be infected by Oo , and high human disturbance (human frequentation and direct impact on snakes) was associated with a higher Oo prevalence, whereas season, body condition and snake species introduction was not. This study suggests that Switzerland might represent a region characterised by high genetic variability in Oo , and where long-term monitoring might be particularly important to follow the evolution of the disease in free-ranging snakes.
... The causative agent, Ophidiomyces ophidiicola, has been established via experimental infection studies in snakes from the families Viperidae and Colubridae [5,11,12]. This keratinophilic fungus utilizes a variety of carbon and nitrogen sources and can survive and grow under a wide range of environmental conditions [13]. Recent work isolated O. ophidiicola from the soil of snake hibernacula, but found that fungal growth was inhibited by microbial communities naturally found in soil, indicating that this is a specialized pathogen of snakes that uses soil as an environmental reservoir [14]. ...
... Previous phylogenetic analyses placed O. ophidiicola isolates from wild European snakes in a different clade than isolates from wild North American snakes, whereas O. ophidiicola isolates from snakes under human care and a wild snake from Taiwan were assigned to a third clade [16,17]. Furthermore, differences in the fungal growth rate in culture were found between the strains isolated from wild European and North American snakes and between strains isolated from a plains garter snake (Thamnophis radix) and an eastern massasauga rattlesnakes (Sistrurus catenatus), both from the state of Illinois [13,16]. Within the United States, differences in pathogen genetics and disease characteristics indicate that multiple lineages are present that could vary in virulence [13,17]. ...
... Furthermore, differences in the fungal growth rate in culture were found between the strains isolated from wild European and North American snakes and between strains isolated from a plains garter snake (Thamnophis radix) and an eastern massasauga rattlesnakes (Sistrurus catenatus), both from the state of Illinois [13,16]. Within the United States, differences in pathogen genetics and disease characteristics indicate that multiple lineages are present that could vary in virulence [13,17]. Additionally, the current literature has identified significant variation in the presentation of ophidiomycosis across species and between individual snakes [6,7,9,[18][19][20][21]. ...
Ophidiomycosis (snake fungal disease) is an infectious disease caused by the fungus Ophidiomyces ophidiicola to which all snake species appear to be susceptible. Significant variation has been observed in clinical presentation, progression of disease, and response to treatment, which may be due to genetic variation in the causative agent. Recent phylogenetic analysis based on whole-genome sequencing identified that O. ophidiicola strains from the United States formed a clade distinct from European strains, and that multiple clonal lineages of the clade are present in the United States. The purpose of this study was to design a qPCR-based genotyping assay for O. ophidiicola, then apply that assay to swab-extracted DNA samples to investigate whether the multiple O. ophidiicola clades and clonal lineages in the United States have specific geographic, taxonomic, or temporal predilections. To this end, six full genome sequences of O. ophidiicola representing different clades and clonal lineages were aligned to identify genomic areas shared between subsets of the isolates. Eleven hydrolysis-based Taqman primer-probe sets were designed to amplify selected gene segments and produce unique amplification patterns for each isolate, each with a limit of detection of 10 or fewer copies of the target sequence and an amplification efficiency of 90–110%. The qPCR-based approach was validated using samples from strains known to belong to specific clades and applied to swab-extracted O. ophidiicola DNA samples from multiple snake species, states, and years. When compared to full-genome sequencing, the qPCR-based genotyping assay assigned 75% of samples to the same major clade (Cohen’s kappa = 0.360, 95% Confidence Interval = 0.154–0.567) with 67–77% sensitivity and 88–100% specificity, depending on clade/clonal lineage. Swab-extracted O. ophidiicola DNA samples from across the United States were assigned to six different clonal lineages, including four of the six established lineages and two newly defined groups, which likely represent recombinant strains of O. ophidiicola. Using multinomial logistic regression modeling to predict clade based on snake taxonomic group, state of origin, and year of collection, state was the most significant predictor of clonal lineage. Furthermore, clonal lineage was not associated with disease severity in the most intensely sampled species, the Lake Erie watersnake (Nerodia sipedon insularum). Overall, this assay represents a rapid, cost-effective genotyping method for O. ophidiicola that can be used to better understand the epidemiology of ophidiomycosis.
... The emergence of fungal pathogens has already had devastating effects on global populations, for example, (1) white-nose syndrome in bats, caused by Pseudogymnoascus destructans (Blehert et al., 2009;Hoyt et al., 2018), and (2) chytridiomycosis in amphibians (caused by Batrachochytrium dendrobatidis and B. salamandrivorans) (Rachowicz et al., 2005;Skerratt et al., 2007Martel et al., 2013. There are concerns that fungal diseases may cause local extinction in snakes, in concert with habitat fragmentation and perhaps climate change (Allender et al., 2015a;Clark et al., 2011). Snake fungal disease (SFD, also called ophidiomycosis) is caused by Ophidiomyces ophidiicola, which can cause severe disease and mortality in some species (Allender et al., 2015a(Allender et al., , 2016Latney & Wellehan, 2020;Lorch et al., 2016). ...
... There are concerns that fungal diseases may cause local extinction in snakes, in concert with habitat fragmentation and perhaps climate change (Allender et al., 2015a;Clark et al., 2011). Snake fungal disease (SFD, also called ophidiomycosis) is caused by Ophidiomyces ophidiicola, which can cause severe disease and mortality in some species (Allender et al., 2015a(Allender et al., , 2016Latney & Wellehan, 2020;Lorch et al., 2016). SFD has been identified in many snake species in the eastern USA. ...
... Laboratory experiments have confirmed that SFD is caused by O. ophidiicola and that snakes experimentally infected develop the abnormalities and altered behavior seen in some wild snake species from which the fungus has been isolated (Allender et al., 2015b;Lorch et al., 2015;McKenzie et al., 2020McKenzie et al., , 2021. Allender et al. (2015a) demonstrated that O. ophidiicola can utilize many carbon sources and is capable of growth (albeit slower than optimal growth) at low temperatures consistent with what might be encountered in snake hibernacula. Paré and Sigler (2016) subsequently hypothesized that hibernacula could serve as transmission sites for snakes and that mortality could be "substantial" in hibernacula where snakes congregate. ...
Snake fungal disease, caused by Ophidiomyces ophidiicola, is recognized as a potential concern for North American snakes. We tested skin swabs from Northern Pine Snakes (Pituophis melanoleucus melanoleucus) in the New Jersey pinelands for the presence of O. ophidiicola before emergence from hibernation. We used qPCR to test the collected swabs for the presence of O. ophidiicola, then determined pathogen prevalence as a function of sampling year, sampling location (skin lesion, healthy ventral skin, healthy head skin) sex, and age. There were no temporal trends in O. ophidiicola detection percentages on snakes, which varied from 58 to 83% in different years. Ophidiomyces ophidiicola detection on snakes was highest in swabs of skin lesions (71%) and lowest in head swabs (29%). Males had higher prevalence than females (82% versus 62%). The fungus was not detected in hatchling snakes (age 0) in the fall, but 75% of juveniles tested positive at the end of hibernation (age 1 year). We also screened hibernacula soil samples for the presence of O. ophidiicola. Where snakes hibernated, 69% of soil samples were positive for O. ophidiicola, and 85% of snakes lying on positive soil samples also tested positive for the pathogen. Although a high proportion of snakes (73%) tested positive for O. ophidiicola during our 4-year study, the snakes appeared healthy except for small skin lesions. We conclude that O. ophidiicola prevalence is high on hibernating Northern Pine Snakes and in the hibernacula soil, with a strong association between snakes and positive adjacent soil. This is the first demonstration that snakes likely become infected during hibernation.
... EIFDs are thus now considered one of the greatest threats to extinction for host species (Mitchell et al., 2008). Yet, EIFDs and their transmission remain poorly understood (Allender et al., 2015;Fisher et al., 2012;Warnecke et al., 2012). ...
... Given the limited previous research, it is not yet known whether N. barbatae is directly transmitted from host to host and/or indirectly transmitted between substrate and host. It may follow a similar transmission pathway to many fungal pathogens which persist saprophytically in the environment (Allender et al., 2015), thus facilitating transmission between substrate and host (Rowley & Alford, 2007). If N. barbatae does follow an indirect transmission pathway and there is limited direct transmission from host to host, then we would not expect to observe any changes in social behaviour to avoid diseased individuals. ...
... Finally, the biology of fungal pathogens may also contribute to a limited capacity for social avoidance behaviours. Unlike many other viral and bacterial pathogens, fungal pathogens persist saprophytically in the environment (Allender et al., 2015), which makes them difficult to detect and facilitates transmission between substrate and host, as well as between hosts (Rowley & Alford, 2007). EIFDs therefore pose real challenges to wildlife, as this additional transmission pathway may mean that socially distancing would not be a sufficient mechanism to mitigate the risk of pathogen exposure or disease transmission (Fairbanks et al., 2015;Loehle, 1995). ...
Emerging infectious fungal diseases are responsible for the extinction of myriad species across a range of phyla. As recently shown by the COVID-19 pandemic, social transmission can be key to disease spread, and in this context, humans are not alone in trying to be alone. In group-living species, individuals have been shown to use social behaviour to avoid infection; diseased individuals can isolate from the group, or healthy animals can avoid diseased conspecifics. However, little is known about social behaviour as a mechanism to avoid fungal infection. In this study, we investigated the extent to which wild urban eastern water dragons, Intellagama lesueurii, a gregarious reptile, modify their social behaviour as a response to infection with a recently emerged infectious fungal disease, caused by the pathogen Nannizziopsis barbatae. Using individual data from a long-term study population inhabiting Roma Street Parkland in Brisbane's Central Business District (QLD, Australia) and focal sampling, we tested whether dragons exhibit self-isolation and social-distancing behaviours in the context of dyadic social approach events. Our results suggested that while the presence of the fungal disease had no effect on individuals' social behaviour, its severity did. Specifically, we found that (1) diseased individuals were no less social than their nondiseased conspecifics, (2) nondiseased individuals did not avoid or spend less time with diseased conspecifics, and (3) models considering the severity of skin lesions caused by N. barbatae, instead of their presence or absence, suggested that individuals avoided more severely diseased conspecifics regardless of their own disease status.
... Various Oo traits, such as the ability to be cultivated on different decaying (autoclaved) organisms, led to the suggestion that it is a saprobe fungus (Allender et al. 2015c). Its suitability to different environments is supported by its capability of growing in a broad range of pH and temperatures in vitro, tolerating air dryness (matric-induced water stress) and most natural sulfur compounds, and its ability to use various complex carbon and nitrogen sources (Allender et al. 2015c). ...
... Various Oo traits, such as the ability to be cultivated on different decaying (autoclaved) organisms, led to the suggestion that it is a saprobe fungus (Allender et al. 2015c). Its suitability to different environments is supported by its capability of growing in a broad range of pH and temperatures in vitro, tolerating air dryness (matric-induced water stress) and most natural sulfur compounds, and its ability to use various complex carbon and nitrogen sources (Allender et al. 2015c). The microorganism can grow on soil medium (TWRA 2017) and can be detected in natural soil (Walker et al. 2019;Campbell et al. 2021). ...
... Although ophidiomycosis is now considered a wide threat to snake populations, the specific effect on free-ranging snakes is poorly known ). Many studies focused on the detection of Oo in single individuals and, therefore, our understanding of the real impact of this disease on natural populations is far from complete (Allender et al. 2015c). ...
Ophidiomyces ophidiicola (Oo) is one of the most relevant fungal pathogens for snakes. It is the etiological agent of ophidiomycosis, an emerging disease causing dysecdysis, skin abnormalities, crusting cutaneous lesions, and ulcerations. Despite this major tegumentary “tropism”, Oo infection can be systemic and it is capable of inducing visceral lesions. Moreover, ophidiomycosis may lead to abnormalities of reproductive physiology, hunting behavior, and thermoregulation, thus increasing the risks of sublethal effects and predation on affected snakes. Oo seems horizontally transmitted and can induce postnatal mortality. This article reviews published data on Oo detection and infection in all snake species in countries around the world and categorizes these data using new classification parameters. The presence of this fungus has been recorded in 11 states (considering the USA as a whole); however, in four states, the mycosis has only been reported in snakes held in captivity. Detection and/or infection of Oo has been ascertained in 62 snake species, divided into nine families. The taxa have been categorized with diagnostic criteria in order to report, for each species, the highest rank of categorization resulting from all cases. Therefore, 20 species have been included within the class “Ophidiomycosis and Oo shedder”, 11 within “Ophidiomycosis”, 16 in “Apparent ophidiomycosis”, and 15 within “Ophidiomyces ophidiicola present”. We also discuss the significance and limits of case classifications and Oo’s impact on wild populations, and we suggest methods for preliminary surveillance. Standardized methods, interdisciplinary studies, and cooperation between various research institutions may facilitate further Oo screening studies, elucidate the unclear aspects of the disease, and protect ophidiofauna from this emerging threat at the global level.
... Ophidiomycosis (snake fungal disease, SFD) is an infectious disease caused by the fungus Ophidiomyces ophidiicola (Allender et al., 2015a;Lorch et al., 2015;McKenzie et al., 2020). Clinical signs of ophidiomycosis typically involve the skin and include displaced scales, scabs, pustules, subcutaneous nodules, ocular cloudiness, necrotic scales, ulcers, and facial disfiguration (Baker et al., 2019). ...
... Clinical signs of ophidiomycosis typically involve the skin and include displaced scales, scabs, pustules, subcutaneous nodules, ocular cloudiness, necrotic scales, ulcers, and facial disfiguration (Baker et al., 2019). The transmission of O. ophidiicola is not well understood; however, it is believed that the pathogen is present in environmental sources, such as soil (Campbell et al., 2021), as well as being spread through contact between animals (Allender et al., 2015a). Ophidiomycosis is proposed as a threat to snake biodiversity throughout the eastern United States (Lorch et al., 2016) and is suspected to be associated with a 50% decline of a population of New Hampshire Timber Rattlesnakes (Crotalus horridus; Clark et al., 2011). ...
... However, the presence of ophidiomycosis in snakes utilizing multiple habitat types (sand, clay, soil, water) in this study indicates that multiple substrates may harbor the fungus. The occurrence of O. ophidiicola across a range of habitats is consistent with in vitro observations that the fungus grows well with a range of nitrogen and carbon sources and is tolerant of a wide range of temperature, pH, and soil moisture (Allender et al., 2015a). The conversion of the ACWS landfill into a more ecologically functioning landscape using native plant species offered a unique opportunity to observe the impact of soil manipulation and sensitive management strategies on this disease system. ...
Ophidiomycosis (snake fungal disease; SFD) is a disease of conservation concern caused by the fungus Ophidiomyces ophidiicola that threatens the health of snake populations worldwide. Gaps exist in our knowledge about the prevalence of this disease across landscapes. In our study, we compared the prevalence of ophidiomycosis between a low-impacted forest site (n = 93) and a highly disturbed remediated landfill (n = 53) in Anderson County, Tennessee, USA. Free-ranging snakes were examined for the presence of skin lesions that are consistent with ophidiomycosis and were swabbed to detect O. ophidiicola DNA using quantitative PCR (qPCR). Apparent ophidiomycosis (qPCR-positive and skin lesions present) was diagnosed at both sites, but there was no significant difference in prevalence between the two sites (24.7% at the forest site; 22.6% at the landfill site). Apparent ophidiomycosis was most prevalent in Racers (38%; Coluber constrictor) and Ring-Necked Snakes (26%; Diadophis punctatus). There was no difference in ophidiomycosis status between sites for the most-sampled species: Racers, Black Rat Snakes (Pantherophis obsoletus), and Ring-necked Snakes (Diadophis punctatus). Our study represents the first report of ophidiomycosis at focal sites in Tennessee. The findings suggest that O. ophidiicola may be ubiquitous across the landscape and point to the need for further study of diverse habitat types for the prevalence of O. ophidiicola.
... Factors that contribute to the probability of Oo infection and mortality among individuals and species vary considerably, although some studies have shown climate and season are associated with incidence and severity of infection 12,17,18,[40][41][42] . However, interspecific 43 and demographic factors 18 associated with pathogen prevalence are still understudied. ...
... Prime examples of fungal infections in wildlife across the globe include chytridiomycosis caused by Batrachochytrium dendrobatidis [2][3][4] or B. salamandrivorans [5][6][7] in amphibians, as well as white-nose syndrome caused by Pseudogymnoascus destructans infections in bats [8][9][10][11] . Similarly, the ascomycete fungus Ophidiomyces ophiodiicola (Oo) is the causative agent of ophidiomycosis (Snake Fungal Disease), an EID in North America and Europe that was also recently detected in Asia [12][13][14][15] . Signs of infection first appear as dermatitis, and if not cleared, infections will advance to lesions, ulcers, and tissue necrosis-the latter of which can precede death 12,16 . ...
... Similarly, the ascomycete fungus Ophidiomyces ophiodiicola (Oo) is the causative agent of ophidiomycosis (Snake Fungal Disease), an EID in North America and Europe that was also recently detected in Asia [12][13][14][15] . Signs of infection first appear as dermatitis, and if not cleared, infections will advance to lesions, ulcers, and tissue necrosis-the latter of which can precede death 12,16 . ...
The ascomycete fungus Ophidiomyces ophiodiicola (Oo) is the causative agent of ophidiomycosis (Snake Fungal Disease), which has been detected globally. However, surveillance efforts in the central U.S., specifically Texas, have been minimal. The threatened and rare Brazos water snake (Nerodia harteri harteri) is one of the most range restricted snakes in the U.S. and is sympatric with two wide-ranging congeners, Nerodiaerythrogaster transversa and Nerodiarhombifer, in north central Texas; thus, providing an opportunity to test comparative host–pathogen associations in this system. To accomplish this, we surveyed a portion of the Brazos river drainage (~ 400 river km) over 29 months and tested 150 Nerodia individuals for the presence of Oo via quantitative PCR and recorded any potential signs of Oo infection. We found Oo was distributed across the entire range of N. h. harteri, Oo prevalence was 46% overall, and there was a significant association between Oo occurrence and signs of infection in our sample. Models indicated adults had a higher probability of Oo infection than juveniles and subadults, and adult N. h. harteri had a higher probability of infection than adult N. rhombifer but not higher than adult N. e. transversa. High Oo prevalence estimates (94.4%) in adult N. h. harteri has implications for their conservation and management owing to their patchy distribution, comparatively low genetic diversity, and threats from anthropogenic habitat modification.
... Factors that contribute to the probability of Oo infection and mortality among individuals and species vary considerably, although some studies have shown climate and season are associated with incidence and severity of infection 12,17,18,[40][41][42] . However, interspecific 43 and demographic factors 18 associated with pathogen prevalence are still understudied. ...
... Prime examples of fungal infections in wildlife across the globe include chytridiomycosis caused by Batrachochytrium dendrobatidis [2][3][4] or B. salamandrivorans [5][6][7] in amphibians, as well as white-nose syndrome caused by Pseudogymnoascus destructans infections in bats [8][9][10][11] . Similarly, the ascomycete fungus Ophidiomyces ophiodiicola (Oo) is the causative agent of ophidiomycosis (Snake Fungal Disease), an EID in North America and Europe that was also recently detected in Asia [12][13][14][15] . Signs of infection first appear as dermatitis, and if not cleared, infections will advance to lesions, ulcers, and tissue necrosis-the latter of which can precede death 12,16 . ...
... Similarly, the ascomycete fungus Ophidiomyces ophiodiicola (Oo) is the causative agent of ophidiomycosis (Snake Fungal Disease), an EID in North America and Europe that was also recently detected in Asia [12][13][14][15] . Signs of infection first appear as dermatitis, and if not cleared, infections will advance to lesions, ulcers, and tissue necrosis-the latter of which can precede death 12,16 . ...
The ascomycete fungus Ophidiomyces ophiodiicola ( Oo ) is the causative agent of ophidiomycosis (Snake Fungal Disease), which has been detected globally. However, surveillance efforts in the central U.S., specifically Texas, have been minimal. The threatened and rare Brazos water snake ( Nerodia harteri harteri ) is one of the most range restricted snakes in the U.S. and is sympatric with two wide-ranging congeners, N. erythrogaster transversa and N. rhombifer , in north central Texas; thus, providing an opportunity to test comparative host-pathogen dynamics in this system. To accomplish this, we surveyed a portion of the Brazos river drainage (~400 river km) over 29 months and tested 150 Nerodia spp. for the presence of Oo via quantitative PCR and recorded any potential signs of Oo infection. We found Oo was distributed across the entire range of N. h. harteri , Oo prevalence was 46 % overall, and there was a significant association between Oo occurrence and signs of infection in our sample. Models indicated adults had a higher probability of Oo infection than juveniles and subadults, and adult N. h. harteri had a higher probability of infection than adult N. rhombifer but not higher than adult N. e. transversa . High Oo prevalence estimates (94.4%) in adult N. h. harteri has implications for their conservation and management owing to their patchy distribution, comparatively low genetic diversity, and threats from anthropogenic habitat modification.
... 2,4,7,13 Due to its ubiquitous environmental presence and its saprophytic characteristics, ophidiomycosis is a problem for a variety of captive and free-ranging snake species in North America, South America, and Europe. 4,6,7,9,10,12,17,19,21,23,25 Ophidiomyces ophiodiicola (Oo) proved to be the causative agent of ophidiomycosis after experimental infections created through direct application of fungi to the skin or nasolabial pits resulted in the expected lesions. 1, 3,4,14 O. ophiodiicola optimally grows at 258C and at a water pH of nine and growth is inhibited at 378C. ...
... 4,6,7,9,10,12,17,19,21,23,25 Ophidiomyces ophiodiicola (Oo) proved to be the causative agent of ophidiomycosis after experimental infections created through direct application of fungi to the skin or nasolabial pits resulted in the expected lesions. 1, 3,4,14 O. ophiodiicola optimally grows at 258C and at a water pH of nine and growth is inhibited at 378C. 4,20,22 In captive and wild snakes, there is a nonsignificant association with higher humidity and there is seasonality of the disease for free-ranging species, with more cases occurring in winter. ...
... 1, 3,4,14 O. ophiodiicola optimally grows at 258C and at a water pH of nine and growth is inhibited at 378C. 4,20,22 In captive and wild snakes, there is a nonsignificant association with higher humidity and there is seasonality of the disease for free-ranging species, with more cases occurring in winter. 8,13,16,19 Snakes with ophidiomycosis develop cutaneous disease manifesting as varying sizes and thicknesses of yellow to brown crusts over the site of infection and/or granulomas in various organs such as the lung, liver, kidney, adrenal gland, and skeletal muscle. ...
A retrospective review of systemic or localized mycotic infections in captive snakes confirmed via biopsy or necropsy from 1983 to 2017 was performed at the Smithsonian's National Zoological Park. Quantitative polymerase chain reaction (qPCR) confirmed infection with Ophidiomyces ophiodiicola (Oo) in 36.8% (n = 14) of the 38 mycotic infections. Infections with Oo were evenly distributed over the 35-y period and lacked a sex predilection. There was a period prevalence of 4.5% of completed snake necropsy or biopsy cases that were Oo positive. Species affected included green anaconda (Eunectes murinus, n = 4), garden tree boa (Corallus hortulanus, n = 1), false water cobra (Hydrodynastes gigas, n = 5), yellow anaconda (Eunectes notaeus, n = 1), eastern milksnake (Lampropeltis triangulum, n = 1), Brazilian rainbow boa (Epicrates cenchria cenchria, n = 1), and eastern diamondback rattlesnake (Crotalus adamanteus, n = 1). Histopathology demonstrated one or more of the following: heterophilic to necrotizing epidermitis with or without granulomatous dermatitis (n = 12), granulomatous pneumonia (n = 5), granulomatous endophthalmitis (n = 1), and subcutaneous-intramuscular fungal granuloma (n = 1). This study documents the presence of ophidiomycosis in a captive collection for almost 40 years, despite current literature designating it a recently emerging pathogen.
... Snakes in the wild can exhibit skin lesions, behavioral alternations, abnormalities of reproductive physiology, thermoregulation, and other abnormalities that are associated with ophidiomycosis [6,[21][22][23][24]. Snakes infected in the laboratory with O. ophidiicola develop the same kind of skin lesions and abnormalities as do snakes in the wild [21][22][23]. ...
... Snakes in the wild can exhibit skin lesions, behavioral alternations, abnormalities of reproductive physiology, thermoregulation, and other abnormalities that are associated with ophidiomycosis [6,[21][22][23][24]. Snakes infected in the laboratory with O. ophidiicola develop the same kind of skin lesions and abnormalities as do snakes in the wild [21][22][23]. Laboratory experiments demonstrate that O. ophidiicola can grow at the low temperatures that snakes are exposed to in hibernacula during the winter, suggesting that hibernacula may be a source of transmission and increased infection [19]. There are more reports of ophidiomycosis in the winter and following hibernation than at other times of the year [24][25][26]. ...
Ophidiomyces ophidiicola, the fungus causing Snake Fungal Disease (SFD) or ophidiomycosis, is prevalent in North American snakes and can have deleterious population effects. Northern pine snakes (Pituophis melanoleucus melanoleucus) in New Jersey often test positive for ophidiomycosis. In this paper, we use qPCR to examine changes in prevalence from 2018 to 2023, and differences by age, sex, and morphological sampling locations. We swabbed ventral surfaces, head, and cloaca of snakes, and lesions and eyes if there were clinical ophidiomycosis signs. A snake was considered positive if any site was positive by qPCR. The prevalence was 47% (2018), increased to 100% (2022), but declined to 46% in 2023. The prevalence was highest in snakes with lesions (46–100%); head swabs had the lowest rates. The more lesions a snake had, the more likely it was that at least one would be positive. Males had significantly more lesions than females, but the prevalence was similar. In 2023, the prevalence of O. ophidiicola was low, but the prevalence of lesions did not decrease as markedly. We discuss the temporal changes in the positivity for O. ophidiicola and its implications for ophidiomycosis effects, suggesting that the fungus is endemic in this population.
... Ophidiomyces ophidiicola is found on a variety of substrates in a range of environments, and apparently infects snakes opportunistically 25 . Characteristic lesions include crusty scales, superficial pustules, and subcutaneous nodules 23,[26][27][28][29] . ...
... DNA was extracted from swab samples at the Canadian Wildlife Health Centre (CWHC) in Guelph, Ontario, and tested for the presence of O. ophidiicola using a validated real-time polymerase chain reaction (qPCR) assay 25 . The precision and detection limit of the assays were evaluated based on a ten-fold standard curve dilution series of gDNA from 5 to 50,000 fg of DNA. ...
Ophidiomycosis (snake fungal disease) is caused by the fungal pathogen Ophidiomyces ophidiicola, which causes dermal lesions, occasional systemic infections, and in some cases, mortality. To better understand potential conservation implications of ophidiomycosis (i.e., population-level effects), we investigated its impacts on individual fitness in a population of endangered eastern foxsnakes (Pantherophis vulpinus). We tracked 38 foxsnakes over 6 years and quantified body condition, movement patterns, oviposition rates, and survival. Body condition, distance travelled, and oviposition rates were similar between snakes with and without ophidiomycosis. Interestingly, snakes that tested positive for the pathogen travelled farther, suggesting that movement through a greater diversity of habitats increases risk of exposure. Ophidiomycosis did not negatively affect survival, and most apparently infected snakes persisted in a manner comparable to snakes without ophidiomycosis. Only one mortality was directly attributed to ophidiomycosis, although infected snakes were overrepresented in a sample of snakes killed by predators. Overall, our results suggest that ophidiomycosis may have sublethal effects on eastern foxsnakes, but do not suggest direct effects on survival, ovipositioning, or viability of the study population.
... Ophidiomycosis has been identified in numerous Serpentes taxa, many with different scale types and cutaneous microbiota [12,53]. Routes of natural transmission are poorly characterized but are proposed to occur through direct contact with infected soil or other snakes [54,55], a process which is likely affected by scale type, skin microbiome, and natural history of each species [56,57]. Thus, until mechanisms for natural transmission are clarified, intradermal inoculation provides a highly repeatable method for observing the effects of this disease in a host. ...
... This suggests that time alone does not determine severity of lesions and that lesion development at the tissue level occurs more rapidly at the cooler temperature which leads to more advanced, chronic lesions in a shorter timeframe. Importantly, in vitro O. ophidiicola growth is significantly slower at 20˚C compared to 25˚C [54], so more aggressive temperature-driven fungal replication is an unlikely explanation for these findings. ...
Ophidiomycosis is a prevalent and intermittently pervasive disease of snakes globally caused by the opportunistic fungal pathogen, Ophidiomyces ophidiicola. Host response has yet to be fully explored, including the role of temperature in disease progression and hematologic changes. This study enrolled twelve adult prairie rattlesnakes (Crotalus viridis) in an experimental challenge with O. ophidiicola at two temperatures, 26°C (n = 6) and 20°C (n = 6). Each temperature cohort included four inoculated and two control snakes. Assessments involving physical exams, lesion swabbing, and hematology were performed weekly. Differences were observed between inoculated and control snakes in survival, behavior, clinical signs, ultraviolet (UV) fluorescence, hematologic response, and histologic lesions. All inoculated snakes held at 20°C were euthanized prior to study end date due to severity of clinical signs while only one inoculated animal in the 26°C trial met this outcome. In both groups, qPCR positive detection preceded clinical signs with regards to days post inoculation (dpi). However, the earliest appearance of gross lesions occurred later in the 20°C snakes (20 dpi) than the 26°C snakes (13 dpi). Relative leukocytosis was observed in all inoculated snakes and driven by heterophilia in the 20°C snakes, and azurophilia in the 26°C group. Histologically, 20°C snakes had more severe lesions, a lack of appropriate inflammatory response, and unencumbered fungal proliferation and invasion. In contrast, 26°C snakes had marked granulomatous inflammation with encapsulation of fungi and less invasion and dissemination. The results of this study identified that O. ophidiicola-infected rattlesnakes exposed to lower temperatures have decreased survival and more robust hematologic change, though minimal and ineffective inflammatory response at site of infection. Ophidiomycosis is a complex disease with host, pathogen, and environmental factors influencing disease presentation, progression, and ultimately, survival. This study highlighted the importance of temperature as an element impacting the host response to O. ophidiicola.
... Because spillover might negatively impact as-yet-unreported wild hosts and allow these EIDs to further invade novel environments, with unknown consequences, both pathogens are a concern for conservation (24,25). Perhaps due to the underlying shared evolutionary history of O. ophiodiicola and N. guarroi, SFD and YFD elicit similar disease processes in their hosts, which include necrotizing dermatitis and, in severe cases, the death of the host (17,26,27). Yet despite infecting phylogenetically related host taxa, current observations suggest that both O. ophiodiicola and N. guarroi possess some level of host specificity, and each has been reported from only snakes and lizards, respectively. ...
... Using a combination of gross examination, histopathological analyses, and reisolation of the pathogens, we confirmed that O. ophiodiicola and N. guarroi can each cause disease in both lizard and snake species. Clinical signs of infection in corn snakes inoculated with O. ophiodiicola and bearded dragons inoculated with N. guarroi (both "typical" hosts of the respective pathogens) followed the expected progression of disease detailed in the literature (7,9,17,21,26,28,29). ...
Host range and specificity are key concepts in the study of infectious diseases. However, both concepts remain largely undefined for many influential pathogens, including many fungi within the Onygenales order. This order encompasses reptile-infecting genera (Nannizziopsis, Ophidiomyces, and Paranannizziopsis) formerly classified as the Chrysosporium anamorph of Nannizziopsis vriesii (CANV). The reported hosts of many of these fungi represent a narrow range of phylogenetically related animals, suggesting that many of these disease-causing fungi are host specific, but the true number of species affected by these pathogens is unknown. For example, to date, Nannizziopsis guarroi (the causative agent of yellow fungus disease) and Ophidiomyces ophiodiicola (the causative agent of snake fungal disease) have been documented only in lizards and snakes, respectively. In a 52-day reciprocal-infection experiment, we tested the ability of these two pathogens to infect currently unreported hosts, inoculating central bearded dragons (Pogona vitticeps) with O. ophiodiicola and corn snakes (Pantherophis guttatus) with N. guarroi. We confirmed infection by documenting both clinical signs and histopathological evidence of fungal infection. Our reciprocity experiment resulted in 100% of corn snakes and 60% of bearded dragons developing infections with N. guarroi and O. ophiodiicola, respectively, demonstrating that these fungal pathogens have a broader host range than previously thought and that hosts with cryptic infections may play a role in pathogen translocation and transmission. IMPORTANCE Our experiment using Ophidiomyces ophiodiicola and Nannizziopsis guarroi is the first to look more critically at these pathogens' host range. We are the first to identify that both fungal pathogens can infect both corn snakes and bearded dragons. Our findings illustrate that both fungal pathogens have a more general host range than previously known. Additionally, there are significant implications concerning the spread of snake fungal disease and yellow fungus disease in popular companion animals and the increased chance of disease spillover into other wild and naive populations.
... Ophidiomycosis is thought to only affect snakes, with cases reported worldwide in colubrid snakes (e.g., Pantherophis sp., Nerodia sp., Natrix sp., Lampropeltis sp., Thamnophis sp.), viperids (e.g., Agkistrodon sp., Crotalus sp., Sistrurus sp.), Acrochordidae, and boids, elapids, and pythonids [31,51]. Ophidiomycosis is likely overreported in colubrids and viperids in comparison to other species, no doubt because of the important surveillance and research effort in North American snakes; the true number of susceptible species is likely more important than currently reported [4,11,27,46,49,[52][53][54][55]. Ophidiomycosis was reported for the first time in Europe in 1985 in a captive ball python (Python regius) [27], in captive snakes in Japan [56], and in wild snakes in Hong Kong in 2019 [55] and in Taiwan in 2021 [54]. ...
... Ophidiomyces ophidiicola is a saprobe with a particular tropism for keratinized environments. Growth is inhibited below 7 • C and above 35 • C, with an optimal temperature of 25 • C [52]. Lesions can be found anywhere along the body, but they initially present as pustular and then crusting dermatitis, involving the face, precorneal scales, thermosensitive dimples, ventral body surface, and the pericloacal region [35] (Figure 2). ...
Emerging infectious diseases (EIDs) are caused by pathogens that have undergone recent changes in terms of geographic spread, increasing incidence, or expanding host range. In this narrative review, we describe three important fungal EIDs with keratin trophism that are relevant to reptile and amphibian conservation and veterinary practice. Nannizziopsis spp. have been mainly described in saurians; infection results in thickened, discolored skin crusting, with eventual progression to deep tissues. Previously only reported in captive populations, it was first described in wild animals in Australia in 2020. Ophidiomyces ophidiicola (formely O. ophiodiicola) is only known to infect snakes; clinical signs include ulcerating lesions in the cranial, ventral, and pericloacal regions. It has been associated with mortality events in wild populations in North America. Batrachochytrium spp. cause ulceration, hyperkeratosis, and erythema in amphibians. They are a major cause of catastrophic amphibian declines worldwide. In general, infection and clinical course are determined by host-related characteristics (e.g., nutritional, metabolic, and immune status), pathogens (e.g., virulence and environmental survival), and environment (e.g., temperature, hygrometry, and water quality). The animal trade is thought to be an important cause of worldwide spread, with global modifications in temperature, hygrometry, and water quality further affecting fungal pathogenicity and host immune response.
... Swab samples were stored at room temperature and sent to the Animal Health Laboratory (Guelph, Ontario, Canada). Extraction of DNA and testing for O. ophidiicola followed the methods described in McKenzie et al. (2020a) and Davy et al. (2021), using a previously described quantitative PCR (qPCR) assay (Allender, Raudabaugh, Gleason, et al. 2015). Standard curves were generated using the cycle threshold (Ct) values of the positive control plasmid dilutions. ...
... It remains unclear how O. ophidiicola is transmitted to and among individuals or how often it occurs as an environmental pathogen. Ophidiomyces ophidiicola can use multiple sources of carbon and nitrogen, tolerates pH ranges (5-11), temperatures (10-35 C), and high sulfur levels common in soil and grows well on dead organisms in vitro (Allender, Raudabaugh, Gleason, et al. 2015). However, certain soil microbe and fungal communities suppress growth of O. ophidiicola, and it is more likely to be detected in soils in underground hibernacula than in topsoils , suggesting that it may have limited ability to thrive when not on a snake host. ...
Ophidiomycosis in snakes is caused by the fungus Ophidiomyces ophidiicola. Clinical signs associated with the disease range from minor skin lesions to severe swelling of the face. In some cases, the fungus invades the snake's underlying muscle and bone and internal organs; disease severity appears to peak during brumation. We quantified the prevalence of O. ophidiicola and ophidiomycosis in free-ranging snakes to explore seasonal variation in detection of the pathogen and disease. We collected skin swabs (n=464 samples) from seven species of free-ranging snakes (n=336) from Rondeau Provincial Park (Ontario, Canada) and tested the swabs for O. ophidiicola using real-time PCR. We also assessed individuals for lesions consistent with ophidiomycosis and monitored changes in gross lesions over time in recaptured individuals. Eastern foxsnakes (Pantherophis vulpinus) had the highest prevalence of O. ophidiicola (24/84) and of lesions consistent with ophidiomycosis (34/84). On other species (Nerodia sipedon, Storeria dekayi, Thamnophis sirtalis, and Thamnophis sauritus), we detected the pathogen on only 4/229 snakes and observed gross lesions consistent with ophidiomycosis on 24/229 snakes. Body length of eastern foxsnakes was associated with detection of O. ophidiicola, suggesting that eastern foxsnakes' large size increases the risk of pathogen exposure relative to the other, smaller, species at our study site. Ophidiomyces ophidiicola and lesions consistent with ophidiomycosis were detected most frequently in eastern foxsnakes soon after emergence from brumation and less frequently later in the active season (O. ophidiicola: April=29.8%, October=3.9%; lesions: April=36.1%, October=5.5%). This decrease corresponded with resolution of lesions in 6/13 resampled eastern foxsnakes. Considering the seasonal cycle of O. ophidiicola and ophidiomycosis when planning disease surveillance research may improve detection probabilities for ophidiomycosis in Nearctic snakes.
... This fungus is the causative agent of snake fungal disease (SFD, or ophidiomycosis), which can range from mild infection to severe morbidity and mortality with consequent snake population declines. 2 So far, infections from O. ophidiicola have been reported in snakes only. 5 The genus Ophidiomyces, which includes the single species O. ophidiicola (formerly Chrysosporium ophiodiicola) is currently placed in the Onygenales order within the Onygenaceae family. ...
... Colony morphology and sporulation of fungus were similar to observations of other authors. 2,12 It should be noted that the colony morphology of O. ophidiicola can easily be confused with other reptilian pathogens belonging to the genera Nannizziopsis and Paranannizziopsis. Preliminary morphology-based identification of isolated fungus was Nannizziopsis guarroi, which frequently has been isolated from pet lizards at VIEV. 10 However, on microscopy, N. guarroi is characterized by the presence of sessile aleuroconidia, whereas arthroconidia are predominant in O. ophidiicola. ...
Three file snakes (Acrochordus granulatus) were delivered to the Moscow Zoo (Russia) from Jakarta (Indonesia). Shortly after arrival, multiple white blisters were detected on their bodies. All three snakes died within a month of arrival. On microscopy, arthrospores and mycelium were seen in exudate from the lesions. Ophidiomyces ophidiicola was isolated from two of three snakes and identified by internal transcribed spacer sequencing. Dermatophyte test medium turned red in positive cultures and can be potentially employed for
detection of O. ophidiicola, the causative agent of snake fungal disease. This is the first report of O. ophidiicola in Russia and the second reported case of ophidiomycosis in file snakes. The possible source of O. ophidiicola in snakes imported from Southeast Asia is discussed.
... The distribution of SFD and its suspected prevalence in monitored snake populations has increased since 2009 (Rajeev et al., 2009;Clark et al., 2011;Allender et al., 2015a;Lorch et al., 2015;Grisnik et al., 2018;Walker et al., 2019). Data suggest that O. ophidiicola uses soil as a reservoir, can withstand a broad spectrum of temperatures and pH levels, utilizes multiple energy sources, and reproduces asexually (Rajeev et al., 2009;Allender et al., 2015a;Walker et al., 2019). ...
... The distribution of SFD and its suspected prevalence in monitored snake populations has increased since 2009 (Rajeev et al., 2009;Clark et al., 2011;Allender et al., 2015a;Lorch et al., 2015;Grisnik et al., 2018;Walker et al., 2019). Data suggest that O. ophidiicola uses soil as a reservoir, can withstand a broad spectrum of temperatures and pH levels, utilizes multiple energy sources, and reproduces asexually (Rajeev et al., 2009;Allender et al., 2015a;Walker et al., 2019). While the disease is most prominent in the Eastern and Midwestern United States, reports of SFD infections in snakes have emerged among wild snakes in Europe (Franklinos et al., 2017) and captive snakes in Australia (Sigler et al., 2013;Lorch et al., 2016). ...
Snake Fungal Disease (SFD) negatively impacts wild snake populations in the eastern United States and Europe. Ophidiomyces ophidiicola causes SFD and manifests clinically by the formation of heterophilic granulomas around the mouth and eyes, weight loss, impaired vision, and sometimes death. Field observations have documented early seasonal basking behaviors in severely infected snakes, potentially suggesting induction of a behavioral febrile response to combat the mycosis. This study tested the hypothesis that snakes inoculated with Ophidiomyces ophidiicola would seek elevated basking temperatures to control body temperature and behaviorally induce a febrile response. Eastern ribbon snakes (Thamnophis saurita, n = 29) were experimentally or sham inoculated with O. ophidiicola. Seven days after inoculation, snakes were tested on a thermal gradient and the internal body temperature and substrate temperature of each snake was recorded over time. Quantitative PCR was used when snakes arrived, during pre-inoculation, and post-inoculation to test snakes for the presence of O. ophidiicola. Some snakes arrived with O. ophidiicola and were subsequently inoculated, allowing for an assessment of secondary exposure effects. Snake thermoregulatory behavior was compared between 1) O. ophidiicola inoculated vs. sham inoculated treatments, 2) infected vs. disease negative groups, and 3) disease naïve vs. pre-exposed immune response categories. Neither internal nor substrate temperatures differed among initially prescribed, and qPCR recovered disease states, although infected snakes tended to reach a preferred body temperature faster than disease negative snakes. Snakes experiencing their first exposure (disease naïve) sought higher substrate temperatures than snakes experiencing their second exposure (pre-exposed). Here, we recover no evidence for behaviorally induced fever in snakes with SFD but do elucidate a febrile immune response associated with secondary exposure.
... cause mycosis in day geckos (Phelsuma sp.) [22], captive Parson's (Caluma parsonii), carpet (Chamaeleo lateralis) and Jackson's chameleons (Chamaleo jacksoni), and in several species of crocodiles and lizards [19,23,29]. Similarly, Ophidiomyces ophiodiicola is responsible for snake fungal disease [2]. Nevertheless, fungal records in giant tortoises are scarce. ...
Galapagos giant tortoises are among the most iconic reptile species on earth; however, an increase in anthropogenic activities has created new challenges for their health and well-being. The presence of whitish lesions on the carapace of Galapagos tortoises (Chelonoidis spp.) was previously described, potentially due to fungal growths, but its etiology remained unexplored. Aiming to close this gap, we analyzed carapace scrapes from six different species of free-living giant tortoises of Santa Cruz, Isabela, San Cristobal, and Española islands. In total, we tested 145 fresh and frozen carapace scrapes from 145 individuals with carapace whitish lesions (W-L, n = 80) and without them (W-O, n = 65), using panfungal endpoint PCRs for the ITS and D1-D2 regions. Aphanoascella galapagosensis was detected in W-L samples from all tortoise species and in none of the W-O samples. Four A. galapagosensis nucleotide sequence types (ST) obtained by using the D1-D2 protocol were identified in these tortoises; ST1 was detected on Santa Cruz, Isabela, and Española Islands whereas ST2 and ST3 were only detected on Isabela, and ST4 on San Cristobal. Neodevriesia spp. and Elsinoe spp. were the most common microorganisms found in W-O samples. These results suggest that A. galapagosensis is the etiological agent of whitish lesions in tortoise carapace contributing to baseline data on carapace fungi in giant Galapagos tortoises. Further research is needed to assess the prevalence and potential pathogenicity of A. galapagosensis and its impact for the conservation of these endangered species.
... For reptiles, most of the fungi associated with disease belong to the Onygenales order, which includes genera such as Ophidiomyces, Emydomyces, Nannizziopsis, and Paranannizziopsis [20,21]. Although knowledge on the role of these fungal pathogens as threats for wild snakes in Europe is limited [22], concerns have grown in recent years around ophidiomycosis, also known as snake fungal disease (SFD), caused by the keratinophilic fungus Ophidiomyces ophidiicola (Oo; see [23][24][25][26]). ...
Ophidiomycosis, caused by the keratinophilic fungus Ophidiomyces ophidiicola (Oo), is an emerging threat to snake populations, yet its epidemiology in Europe remains underexplored. We investigated the distribution of Oo across free-ranging snake populations in Italy, integrating both recent field samples and historical museum specimens. Our survey involved 423 snakes representing 17 species from 17 regions, with Oo detected in 32 snakes from five different species. Additional molecular detection for Parananniziopsis spp. on a subset of 13 Oo-negative samples from snakes that exhibited clinical signs yielded negative results. Acknowledging the non-standardised sampling and the limited sample size, our findings highlight Oo’s persistent and widespread presence across diverse ecological zones, particularly affecting semi-aquatic species like Natrix tessellata. While Oo Clade I was primarily found in museum specimens, indicating a historical presence, Clade II prevailed in recent samples. This highlights a complex epidemiological landscape where different clades may influence the current disease dynamics. Our results underscore the importance of continuous surveillance and highlight the need for standardised sampling to better understand snake fungal disease ecology and epidemiology in Italy.
... To date, the negative impacts of Ophidiomyces are controversial (Di Nicola et al. 2022). For some species it appears to be negatively impacting the conservation of their populations (Allender et al., 2015) but in other cases ophidiomycosis may have sublethal effects and no direct effects on survival, ovipositioning, or viability of the studied populations (Dillon et al. 2024). This pathogen is suspected to be associated with the declines of some snake populations in North America and recently has been detected in European wild snakes (Blanvillaine et al. 2022;Joudrier et al. 2024). ...
Boletin de la Asociacion Herpetologica Española (2024): 35(2). We describe a new case of the fungal pathogen Ophidiomyces ophidiicola detected in 2024 in the Pyrenees (Catalonia, North-East Spain) and affecting a new host belonging to the species Coronella girondica (Southern smooth snake).
... O. ophidiicola is believed to be horizontally transmitted [16] and can persist in soil, particularly in hibernacula (overwintering sites), which may serve as reservoirs for the pathogen [17]. It can grow across a broad range of pH levels and temperatures, and it exhibits tolerance to air dryness and various natural sulphur compounds [18]. Whereas its growth can be inhibited by other soil microbes, it thrives in sterilised soil, suggesting that natural microbial communities play a role in suppressing its proliferation [17]. ...
Ophidiomyces ophidiicola, the causative agent of ophidiomycosis, poses a potential threat to wild snakes worldwide. This study aimed to retrospectively investigate the prevalence of O. ophidiicola in archived snake moults collected from the San River Valley in the Bieszczady Mountains, Poland, from 2010 to 2012. Using qPCR for O. ophidiicola detection and conventional PCR for clade characterisation, we analysed 58 moults and one road-killed specimen of Zamenis longissimus and Natrix natrix. A novel combination of primers (ITS2L) was used to simultaneously confirm SYBR Green-based qPCR results and perform genotyping. O. ophidiicola has been detected from two Z. longissimus and one N. natrix specimens. The identified clade (I-B) is consistent with those found in wild snakes of eastern Europe and San River Valley, indicating that O. ophidiicola has been present in this region for at least a decade. This study underscores the value of historical samples in understanding the long-term presence of pathogens and highlights the potential role of environmental reservoirs in the persistence of O. ophidiicola. Our findings are crucial for informing conservation strategies for the endangered Aesculapian snake populations in Poland, emphasising the need for ongoing monitoring and habitat management to mitigate the potential impact of ophidiomycosis.
... Snakes could generally be identified to species without capture, with the exception of some garter snakes (Thamnophis sp.). Snakes displaying clinical symptoms of Snake Fungal Disease (Allender et al., 2015;Clark et al., 2011) were discovered at multiple sites in 2016, so starting in 2017 any gear that contacted a study animal was sanitized with 99.8% isopropyl alcohol wipes between captures and hands were sanitized with 70% ethanol liquid hand sanitizer (Purell Advanced Hand Sanitizer, GOJO Industries, Inc., Akron, Ohio, USA). This study was conducted under Institutional Animal Care and Use Committee log number 2-16-8204-J. ...
Nearly one in five reptile species is at risk of extinction. Changes in habitat area, its configuration, and vegetation diversity could affect habitat use, but their relative importance is understudied. We assessed how these factors affected reptile presence in agricultural landscapes figure in Iowa, United States, using 695 cover boards visited 16,441 times in 2015–2020. Species‐wise encounter rates ranged 0.0001–0.012. Eight of 11 species and 54.2% of individuals were species of greatest conservation need. Habitat area, configuration, and vegetation diversity influenced reptile presence similarly. Mean patch occupancy was 0.18 for common garter snake (CG, Thamnophis sirtalis ) and 0.45 for all snakes (AS). Naïve presence was explained by effort (odds ratio [OR] AS = 1.83, OR CG = 1.79), vegetation diversity (OR AS = 1.28, OR CG = 1.28), woody cover (OR AS = 1.24, OR CG = 1.41), and patch size (OR AS = 1.30). Large patch prairies were more likely to contain snakes than other conservation practices ( encounter = 0.291), and more likely to contain CG (0.098) than prairie contour strips (0.031), waterways (0.018), grass contour strips (0.016), or terraces (0.015). While we documented low overall reptile presence, their higher presence in large prairie patches underscores the importance of core nature reserves for reptile conservation.
... A scoring system (4-16) was developed, adapted from Baker et al. 30 , to rank the severity of skin lesions based on their characteristics, number, and distribution (See Supplementary Materials). Skin lesion scores were subsequently categorised as very mild (score 4), mild (5)(6)(7)(8), moderate (9)(10)(11)(12), or severe (13)(14)(15)(16). Snakes were also examined for skin injuries with an appearance consistent with trauma, e.g. ...
Ophidiomycosis is an emerging infectious disease affecting wild snakes in the Northern Hemisphere. Recently confirmed in Great Britain, the prevalence, severity and significance of ophidiomycosis has yet to be characterised in free-living snakes at a population level in Europe. Therefore, a population of barred grass snakes (Natrix helvetica) in eastern England was monitored for three seasons (May 2019 to October 2021), to investigate the prevalence (25.5%; 191/750 snakes) and severity of skin lesions and their aetiology. The most frequently observed skin lesion characteristics were changes in scale colour, crusting, and scale margin erosion. The majority of such lesions (96.9%; 185/191 snakes) was observed on the ventral surface along the length of the body. The severity of skin lesions was considered mild in more than half of the cases (53.1%; 98/191 snakes). Predominantly, skin lesions were observed in adult snakes (72.8%; 139/191 snakes). Combined histological examinations and qPCR tests of skin lesions from N. helvetica sloughs and/or carcasses confirmed a diagnosis of ophidiomycosis. Further targeted surveillance, supported by molecular and histological examinations to confirm skin lesion aetiology, is required to determine the extent to which our findings reflect the occurrence of ophidiomycosis in populations within wider landscapes.
... 4,9,11 Experimental infection studies identified the causative agent as Ophidiomyces ophidiicola, a keratinophilic fungus that can persist in soil and grows at a wide range of temperatures and pH. 2,5,10,31,34 Ophidiomyces ophidiicola infection typically causes skin lesions, including displaced and/ or discolored scales, granulomas, and crusting, and can also result in swelling or disfiguration of infected tissues and death. 6 In some cases, the fungus invades into deeper tissues, such as bone and muscle, and granulomas have been found in internal organs. ...
Ophidiomycosis (snake fungal disease) is an important infectious disease caused by the fungus Ophidiomyces ophidiicola. To mitigate the disease's impact on individual snakes, a controlled clinical trial was conducted using terbinafine nebulization to treat snakes with ophidiomycosis. Fifty-three wild-caught Lake Erie watersnakes (Nerodia sipedon insularum) with apparent ophidiomycosis (skin lesions present, qPCR positive for O. ophidiicola) were divided into treatment and control groups: treatment snakes were nebulized with a 2 mg/ml terbinafine solution for 30 min daily for 30 d; control snakes received nebulization with 0.9% saline or no nebulization. Weekly physical exams were conducted to assign disease severity scores based on the number, type, location, and size of lesions, and qPCR was repeated after each 30-d course of treatment. Persistently qPCR-positive snakes received multiple nebulization courses. Terbinafine nebulization showed mixed results as a treatment for ophidiomycosis: 29.2% of animals treated with terbinafine showed molecular resolution of external disease, based on antemortem swabbing, following 3-6 mon of daily nebulization; this was significantly more than with saline nebulization (5%), but molecular resolution also occurred in 11.1% of snakes that received no treatment. Terbinafine nebulization did not significantly decrease clinical disease, as measured by disease severity scores. Evaluating molecular response to treatment using fungal quantities, terbinafine nebulization significantly reduced fungal quantity after three or more courses of treatment. These results indicate that, although terbinafine nebulization is a promising treatment for ophidiomycosis, snakes may require multiple nebulization courses and disease may not always resolve completely, despite treatment. This treatment may be most useful in snakes from managed populations that can be treated for several months, rather than wild snakes who are not releasable after multiple months in captivity.
... The disease has also been demonstrated in captive snakes in Europe (Vissiennon et al. 1999, Picquet et al. 2018, Asia (Takami et al. 2021), North America (Nichols et al. 1999, Bertelsen et al. 2005, Steeil et al. 2018 and Australia (Sigler et al. 2013, WHA Fact Sheet 2021. The most important cause of the worldwide spread of fungal diseases, and a likely cause of the spread of ophidiomycosis, is the animal trade (Allender et al. 2015b, Schillinger et al. 2023. ...
... Ophidiomyces ophidiicola (Oo) is the etiological agent of ophidiomycosis (also known as Snake Fungal Disease -SFD), a fungal infection of snakes . This onygenalean fungus is resistant to various physical and chemical agents (Allender et al., 2015b), and hibernacula may represent its environmental reservoir (Camp-bell et al. 2021). Ophidiomyces infection has been associated with sublethal effects on adults (Agugliaro et al., 2020;Lind et al. 2018a, b;Tetzlaff et al., 2017) and potentially lethal outcomes on newborns (e.g., Britton et al., 2019), translating into a potential impact on wild populations' fitness and a threat to conservation. ...
In the Abruzzi village of Cocullo (Italy), each year, on May 1st, local snake hunters (known as Serpari) display colubrids, captured in the wild, to commemorate the ancient ritual of San Domenico. The ascomycete Ophidiomyces ophidiicola (Oo) is the causative agent of ophidiomycosis, an emerging disease with sublethal effects. Skin lesions, such as dysecdysis, edematous, crusty or necrotic scales, swellings, nodules, and ulcers, are the most common clinical manifestation of the disease. The pathogen and its associated disease are well characterized in wild snakes in North America, whereas broad screenings of free ranging wild ophidians in Europe are rare. In 2019, as part of a multi-year snake health monitoring project, all the Cocullo ophidians were carefully examined for integumentary affections and those showing signs consistent with ophidiomycosis were dry swabbed on the skin and on any visible cutaneous lesions with a single applicator. The extracted DNA underwent a broad-range panfungal PCR targeting the D1-D2 region, as well as two conventional PCRs specific to the ITS2 and IGS regions of Oo DNA. Twenty-three out of 129 snakes (13/82 Elaphe quatuorlineata; 7/31 Hierophis viridiflavus; 3/15 Zamenis longissumus; 0/1 Natrix helvetica) resulted clinically affected, but no specific Oo genomic DNA was detected by PCR. The Cocullo ritual celebration provided a unique opportunity for the first systematic testing of a large sample size of a local snake community for the monitoring of this pathogen in Italy.
... Recently, Oo was detected in Idaho (Allender et al., 2020) and California (Haynes et al., 2021). Thus, it now seems to be distributed across the contiguous U.S. In light of these observations, Oo has been referred to as an emerging fungal pathogen of snakes (Allender, Raudabaugh, et al., 2015;Franklinos et al., 2017;Grioni et al., 2021;Guthrie et al., 2016;McKenzie et al., 2019;Ohkura et al., 2017). However, a recent study proposed that Oo should be viewed as naturally occurring rather than novel, and an unrecognized yet common fungal pathogen of snakes as opposed to a newly emergent pathogen (Davy et al., 2021). ...
Ophidiomyces ophidiicola (Oo) is a fungal pathogen and the causative agent of ophidiomycosis that has affected multiple snake taxa across the United States, Europe, and Asia. Ophidiomycosis has often been referred to as an emerging infectious disease (EID); however, its status as an EID has recently come under debate. Oo infections have been confirmed in wild snake populations in Texas; however, it is unknown if the pathogen is novel (i.e., invasive) or endemic to the state. To address this knowledge gap, we conducted surveys for Oo among preserved Nerodia deposited at three university museums in Texas. First, we visually assessed snakes for signs of infection (SOI), and if SOI were present, we sampled the affected area. We then used quantitative polymerase chain reaction to diagnose the presence of Oo DNA on areas with SOI and used these data to evaluate spatiotemporal patterns of Oo prevalence. We also tested for significant spatial clusters of Oo infenction using a Bernoulli probability model as implemented in the program SatScan. We found that the proportion of snakes exhibiting SOI was constant over time while the prevalence of Oo DNA among those SOI increased across space and time. Within these data, we detected an incidence pattern consistent with an introduction and then spread. We detected six spatial clusters of Oo infection, although only one was significant. Our results support the hypothesis that Oo is an emerging, novel pathogen to Texas snakes. These data narrow the knowledge gap regarding the history of Oo infections in Texas and establish a historical record of confirmed Oo detections in several counties across the state. Thus, our results will guide future research to those areas with evidence of past Oo infections but lacking confirmation in contemporary hosts.
... The disease first gained attention in 2008 when severe fungal infections manifested in a well-studied population of eastern massasauga rattlesnakes (Sistrurus catenatus) in Illinois, USA [21]. Subsequent investigations revealed that SFD was widely distributed in the eastern USA and Great Lakes region of Canada [18,20,22]. The fungus Ophidiomyces ophiodiicola (Oo) is the causative agent of SFD [23,24]. ...
Snake fungal disease (SFD; ophidiomycosis), caused by the pathogen Ophidiomyces ophidiicola ( Oo ), has been documented in wild snakes in North America and Eurasia, and is considered an emerging disease in the eastern USA. However, a lack of historical disease data has made it challenging to determine whether Oo is a recent arrival to the USA or whether SFD emergence is due to other factors. Here, we examined the genomes of 82 Oo strains to determine the pathogen’s history in the eastern USA. Oo strains from the USA formed a clade (Clade II) distinct from European strains (Clade I), and molecular dating indicated that these clades diverged too recently (∼2,000 years ago) for transcontinental dispersal of Oo to have occurred via natural snake movements across Beringia. A lack of nonrecombinant intermediates between clonal lineages in Clade II indicates that Oo has actually been introduced multiple times to North America from an unsampled source population, and molecular dating indicates that several of these introductions occurred within the last few hundred years. Molecular dating also indicated that the most common Clade II clonal lineages have expanded recently in the USA, with time of most recent common ancestor mean estimates ranging from 1985-2007 CE. The presence of Clade II in captive snakes worldwide demonstrates a potential mechanism of introduction and highlights that additional incursions are likely unless action is taken to reduce the risk of pathogen translocation and spillover into wild snake populations.
... Observed seasonal patterns of infection may be driven by the thermal biology of the pathogen and/or host. Like many fungi, Oo growth is inhibited at high temperatures (Allender et al., 2015;Sigler et al., 2013), and seasonally high temperatures or the opportunity for hosts to behaviorally induce fever may explain seasonal patterns. Long-term studies comparing seasonal patterns in prevalence and clinical severity can be useful in identifying environmental factors that may favor host or pathogen and may inform the development of effective management strategies (Bozzuto & Canessa, 2019). ...
Informed and effective management of emerging infectious diseases can be improved by a clear understanding of host–pathogen–environment interactions. Impacts of the seasonal environment on pathogen dynamics and host responses are poorly described in most reptile host–fungal pathogen systems. Here, we describe seasonal patterns of ophidiomycosis, a disease caused by the fungus Ophidiomyces ophidiicola (Oo), in a population of pygmy rattlesnakes, Sistrurus miliarius, in central Florida. We used field observations of gross clinical signs of disease in combination with qPCR on skin swabs to examine the seasonal prevalence of Oo and patterns of clinical presentation in hosts. We monitored thermoregulatory behaviors, ecdysis, and reproductive status in free‐living snakes to examine seasonal associations between infection and host coping responses. Both the prevalence of Oo and clinical signs of disease varied strongly with the season (winter high and summer low). In both seasons, the presence of clinical signs was a strong predictor of the presence of Oo as identified by qPCR on skin swabs (78% probability across seasons). Snakes with clinical signs of disease were more likely to be observed exhibiting thermoregulatory behavior or in ecdysis compared to non‐clinical snakes across seasons. The prevalence of Oo was not significantly different in pregnant snakes compared to other reproductive categories, but pregnant females were less likely to exhibit clinical signs of disease compared to males. Our results highlight strong seasonal patterns in both host clinical signs and Oo prevalence and support the efficacy of using gross clinical signs of disease in combination with qPCR on skin swabs to assess disease dynamics in free‐living snakes. We also identify ecdysis and thermoregulatory behaviors as components of the seasonal disease‐coping response and highlight the need to examine these behaviors as potential drivers of seasonal infection outcomes in reptiles afflicted with fungal pathogens.
... Given the appearance of the ventral dermatitis, we suspected a fungal aetiology. Onygenalean fungi (order: Onygenales) have commonly been associated with dermatitis in reptiles (Paré and Sigler, 2016), specifically Ophidiomyces ophidiicola in free-ranging snakes in North America (Allender et al., 2015;Lorch et al., 2015) and Europe (Franklinos et al., 2017). Additionally, O. ophidiicola and Paranannizziopsis australasiensis have both been reported in Australian aquatic snakes (Sigler et al., 2013). ...
Urban ecosystems and remnant habitat 'islands' therein, provide important strongholds for many wildlife species including those of conservation significance. However, the persistence of these habitats can be undermined if their structure and function are too severely disrupted. Urban wetlands, specifically, are usually degraded by a monoculture of invasive vegetation, disrupted hydrology, and chronic-contamination from a suite of anthropogenic pollutants. Top predators—as bioindicators—can be used to assess and monitor the health of these ecosystems. We measured eight health parameters (e.g., parasites, wounds and scars, tail loss and body condition) in a wetland top predator, the western tiger snake, Notechis scutatus occidentalis. For three years, snakes were sampled across four wetlands along an urban gradient. For each site, we used GIS software to measure the area of landscape variables and calculate an urbanisation–landscape score. Previously published research on snake contamination informed our calculations of a metal-pollution index for each site. We used generalised linear mixed models to assess the relationship between all health parameters and site variables. We found the metal-pollution index to have the most significant association with poor body condition. Although parasitism, tail loss and wounds differed among sites, none of these parameters influenced body condition. Additionally, the suite of health parameters suggested differing health status among sites; however, our measure of contemporary landscape urbanisation was never a significant predictor variable. Our results suggest that the health of wetland predators surrounding a rapidly growing city may be offset by higher levels of environmental pollution.
... The higher risk of apparent ophidiomycosis in May, the coldest month of sampling in this study, as well as the negative correlation between temperature and lesion presence in LEWS correspond to previous reports of a correlation between temperature and ophidiomycosis, with a higher prevalence of O. ophidiicola and more severe clinical signs observed at lower temperatures (McCoy et al. 2017;Hileman et al. 2018). In contrast, previous in vitro work found that O. ophidiicola growth was maximized at 25 C, significantly reduced at 14 C, and inhibited at 7 C (Allender et al. 2015c). Furthermore, seasonality of reproduction is likely to contribute to within-species transmission events and may explain the monthly variation in this species: Lake Erie watersnakes engage in courtship behavior from early May to early June each year (King 1986), during which they are commonly found in mating balls that consist of several males and a single female. ...
Ophidiomycosis, caused by the fungus Ophidiomyces ophidiicola, is an infectious disease of wild and managed snakes worldwide. Lake Erie watersnakes (LEWS; Nerodia sipedon insularum) were listed as threatened under the US Endangered Species Act from 1999 to 2011 and were first diagnosed with ophidiomycosis in 2009. Our objective was to characterize the epidemiology of ophidiomycosis in LEWS. We hypothesized that the prevalence of skin lesions, O. ophidiicola DNA, and ophidiomycosis disease categories would show spatial and temporal variation and clustering, with higher prevalence at sites with greater human disturbance and prevalence increasing over time. Snakes were captured via visual encounter surveys at five sites across four islands and visually inspected for skin lesions suggestive of ophidiomycosis, and then body swabs were collected to detect O. ophidiicola DNA using the quantitative PCR assay. Each snake was assigned an ophidiomycosis category based on the presence of skin lesions and O. ophidiicola. We evaluated 837 LEWS between 2017 and 2020 and detected ophidiomycosis at all five sites. Logistic regression analysis showed temporal and spatial variation in disease, with higher risk of apparent ophidiomycosis (lesions present and O. ophidiicola detected) at Kelleys Island State Park, compared to all other sites; in May, compared to July; and in 2019, compared to 2018. The presence of emerging herbaceous wetlands, urban land change, and certain soil types increased the odds of both lesion presence and quantitative PCR detection of O. ophidiicola. Overall, ophidiomycosis epidemiology varied among sites: the disease appeared to be endemic at most sites and emerging at one site. Ongoing efforts to monitor population health and mortality associated with disease prevalence are needed to inform mitigation aimed at reducing the impact of ophidiomycosis in LEWS.
... During the course of this study we were able to conclusively document the presence of snake fungal disease among two species. This has important implications for the long-term health of this snake community (Allender et al. 2015). Further, we found that native snakes will readily consume non-native birds, even when the birds are relatively well protected. ...
... Reservoirs of potentially infectious material may facilitate consistent exposure to a host, continual reinfection, and potentially a more systemic and fatal disease. Nannizziopsis guarroi can generally tolerate warmer temperatures than such pathogens as O. ophiodiicola and B. dendrobatidis or Batrachochytrium salamandrivorans (Allender et al. 2015;Blooi et al. 2015), which may allow it to persist for longer periods of time and in a greater range of environments in the absence of a host. Research into N. guarroi's native geographic range, natural history, and ecology is critically needed to enable an understanding of the transmission and epidemiology of YFD. ...
Nannizziopsis guarroi is an ascomycete fungus associated with a necrotizing dermatitis in captive green iguanas (Iguana iguana) and bearded dragons (Pogona vitticeps) across both Europe and North America. Clinical signs of the disease include swelling and lesion formation. Lesions develop from white raised bumps on the skin and progress into crusty, yellow, discolored scales, eventually becoming necrotic. The clinical signs are the basis of a colloquial name yellow fungal disease (YFD). However, until now, N. guarroi has not been confirmed as the primary agent of the disease in bearded dragons. In this experiment, we fulfill Koch’s postulates criteria of disease, demonstrating N. guarroi as the primary agent of YFD in bearded dragons.
Emerging infectious diseases are increasingly recognized as a significant threat to global biodiversity conservation. Elucidating the relationship between pathogens and the host microbiome could lead to novel approaches for mitigating disease impacts. Pathogens can alter the host microbiome by inducing dysbiosis, an ecological state characterized by a reduction in bacterial alpha diversity, an increase in pathobionts, or a shift in beta diversity. We used the snake fungal disease (SFD; ophidiomycosis), system to examine how an emerging pathogen may induce dysbiosis across two experimental scales. We used quantitative polymerase chain reaction, bacterial amplicon sequencing, and a deep learning neural network to characterize the skin microbiome of free‐ranging snakes across a broad phylogenetic and spatial extent. Habitat suitability models were used to find variables associated with fungal presence on the landscape. We also conducted a laboratory study of northern watersnakes to examine temporal changes in the skin microbiome following inoculation with Ophidiomyces ophidiicola. Patterns characteristic of dysbiosis were found at both scales, as were nonlinear changes in alpha and alterations in beta diversity, although structural‐level and dispersion changes differed between field and laboratory contexts. The neural network was far more accurate (99.8% positive predictive value [PPV]) in predicting disease state than other analytic techniques (36.4% PPV). The genus Pseudomonas was characteristic of disease‐negative microbiomes, whereas, positive snakes were characterized by the pathobionts Chryseobacterium, Paracoccus, and Sphingobacterium. Geographic regions suitable for O. ophidiicola had high pathogen loads (>0.66 maximum sensitivity + specificity). We found that pathogen‐induced dysbiosis of the microbiome followed predictable trends, that disease state could be classified with neural network analyses, and that habitat suitability models predicted habitat for the SFD pathogen.
The role of the skin microbiome in resistance and susceptibility of wildlife to fungal pathogens has been examined from a taxonomic perspective but skin microbial function, in the context of fungal infection, has yet to be studied. Our objective was to understand effects of a bat fungal pathogen site infection status and course of invasion on skin microbial function. We sampled seven hibernating colonies of Myotis lucifugus covering three-time points over the course of Pseudogymnoascus destructans (Pd) invasion and white nose syndrome (pre-invasion, epidemic and established). Our results support three new hypotheses about Pd and skin functional microbiome: 1) there is an important effect of Pd invasion stage, especially at the epidemic stage; 2) disruption by the fungus at the epidemic stage could decrease anti-fungal functions with potential negative effects on the microbiome and bat health; 3) the collection site might have a larger influence on microbiomes at the pre-invasion stage rather than at epidemic and established stages. Future studies with larger samples size and using meta-omics approaches will help confirm these hypotheses, and determine the influence of the microbiome on wildlife survival to fungal disease.
Serpentoviruses are strongly associated with upper respiratory tract disease in captive and free-ranging bluetongued skinks (Tiliqua spp.). In Australia, bluetongue serpentoviruses were first reported in shingleback skinks (Tiliqua rugosa) with upper respiratory tract disease that presented to wildlife rehabilitation facilities in Perth, Western Australia. Since then, serpentoviruses have been detected commonly in captive bluetongued skinks from most areas of Australia, yet knowledge about the prevalence and distribution of these viruses in free-ranging bluetongued skinks, and other skink species, remains limited. Oral swabs were collected from 162 shingleback skinks from four areas in Western Australia and neighboring South Australia to screen for bluetongue serpentoviruses by PCR. The proportions of PCR positives were 0% (0/4) for Rottnest Island (a small island west of Perth, Western Australia), 3% (1/32) for the Shire of Kent (∼5,600 km2 in the southwest of Western Australia), 1% (1/91) from an approximately 250,000 km2 area across South Australia and Western Australia, and 0% (0/35) from Mount Mary (∼150 km2 in the mid north of South Australia). Neither of the two PCR-positive shingleback skinks had overt signs of upper respiratory tract disease. These results are consistent with serpentoviruses occurring at a relatively low crude prevalence of 1.4% (95% confidence interval, 0.2-4.9%) across these areas, although the potential bias from sampling active and apparently healthy individuals may mean that this estimate is lower than the true prevalence. This contrasts with the high proportion of PCR positives reported in captive individuals. In the absence of experimental or observational data on viral clearance and recovery, Tiliqua spp. skinks that are intended for release into the wild should be housed with strict biosecurity to prevent interactions with captive individuals and screened to ensure that they are not PCR positive before release.
Latin America comprises continental and insular lands from Mexico to Argentina, including Caribbean islands and the Galapagos archipelago. Population declines due to anthropogenic causes such as habitat fragmentation, pollution, invasive species, and global climate change are affecting reptile populations, but there is almost no information about how diseases may affect wild reptiles, and there are few reports on this topic. Most of the studies regarding infectious diseases have been performed in captive animals with mainly known diseases. These studies are important since the legal and illegal trade of reptiles is a constant threat and a massive problem in the region, and potential transmission to wild animals is always a concern. Despite these approaches, studies involving disease ecology are scarce, and most of the research done in reptile health focuses mostly on parasite identification and clinical pathology. This chapter explores the research done on captive animals as a preliminary and important source of information that can be extrapolated to wildlife studies as well as the threat that the reptile trade imposes on wild animals. Finally, the authors propose some urgent studies that have to be done in terms of disease ecology considering the evaluated aspects before.
Emerging infectious diseases in wildlife species caused by pathogenic fungi are of growing concern, yet crucial knowledge gaps remain for diseases with potentially large impacts. For example, there is detailed knowledge about host pathology and mechanisms underlying response for chytridiomycosis in amphibians and white‐nose syndrome in bats, but such information is lacking for other more recently described fungal infections. One such disease is ophidiomycosis, caused by the fungus Ophidiomyces ophidiicola, which has been identified in many species of snakes, yet the biological mechanisms and molecular changes occurring during infection are unknown. To gain this information, we performed a controlled experimental infection in captive Prairie rattlesnakes (Crotalus viridis) with O. ophidiicola at two different temperatures: 20 and 26°C. We then compared liver, kidney, and skin transcriptomes to assess tissue‐specific genetic responses to O. ophidiicola infection. Given previous histopathological studies and the fact that snakes are ectotherms, we expected highest fungal activity on skin and a significant impact of temperature on host response. Although we found fungal activity to be localized on skin, most of the differential gene expression occurred in internal tissues. Infected snakes at the lower temperature had the highest host mortality whereas two‐thirds of the infected snakes at the higher temperature survived. Our results suggest that ophidiomycosis is likely a systemic disease with long‐term effects on host response. Our analysis also identified candidate protein coding genes that are potentially involved in host response, providing genetic tools for studies of host response to ophidiomycosis in natural populations.
Ce rapport présente une évaluation de la translocation en tant que mesure de mitigation pour la couleuvre brune au Québec. Si une translocation à courte distance dans un contexte d’une perturbation temporaire ou de destruction partielle apparait justifiée sans présenter d’enjeux d’efficacité, de risques associés à la propagation de maladies ou à la désorganisation de la diversité génétique, de nombreux enjeux persistent encore aujourd’hui par rapport à la relocalisation hors de l’habitat (longue distance). Parmi ceux-ci figurent la variabilité des taux de succès ainsi que les risques pour les individus relocalisés (haut taux de mortalité) et pour l’espèce.
Face à la perte d’habitat dans la grande région métropolitaine et compte tenu des risques d’échecs, des enjeux pour les individus relocalisés et pour l’espèce, des coûts ainsi que des retombées incertaines affectant uniquement une espèce, il est recommandé de favoriser en priorité des actions de conservation aux bénéfices multispécifiques. Protéger ses habitats, améliorer des habitats existants ou leur connectivité ainsi que renaturaliser des habitats dégradés par les activités anthropiques en sont de bons exemples.
Ophidiomycosis, an infectious disease of snakes caused by the fungus Ophidiomyces ophidiicola , is known to cause skin lesions and, in some cases, deeper infections, and even death. It has been documented in captive snakes worldwide and in free-ranging snakes in the United States and Europe. Diagnostic limitations have impeded characterization of the epidemiology of this disease and subsequent efforts to improve clinical care and conservation outcomes. The purpose of this research was to evaluate the efficacy of qPCR of snake sheds as a noninvasive diagnostic tool for the detection of O. ophidiicola , compared to swabs prior to and following the shed. We tested shed pieces from grossly observed skin lesions or mid body sections if disease was not obvious, and matched skin swabs from 68 animals using a qPCR assay specific for O. ophidiicola . There was nearly complete agreement between the qPCR results of sheds and swabs (Cohen's kappa = 0.97) and sheds were 100% sensitive and 97% specific for apparent ophidiomycosis, with a 97% negative predictive value and a 100% positive predictive value. Our results indicate that qPCR of snake sheds is a reliable detection method for the presence of O. ophidiicola , as this technique has high agreement with peri-ecdysis skin swabbing. Although this technique can be used for noninvasive pathogen detection in captive individuals with known histories, results from snake sheds from free-ranging animals with no knowledge of associated clinical signs should be interpreted with caution and additional surveillance is necessary in these cases.
1. Infectious diseases are influenced by interactions between host and pathogen, and are rarely homogenous across the landscape. Areas with elevated pathogen prevalence maintain a high force of infection, can facilitate pathogen spread to new regions, and may indicate areas with impacts on host populations. However, isolating the ecological processes that result in increases in infection prevalence and intensity remains a challenge.
2. Here we elucidate the contribution of pathogen clade and host species in disease hotspots of Ophidiomyces ophidiicola, the pathogen that causes snake fungal disease, in 21 species of snakes infected with multiple pathogen strains across 10 countries in Europe.
3. We found isolated areas of disease hotspots in a landscape where infections were otherwise low. O. ophidiicola clade had important effects on transmission, and areas with multiple pathogen clades had higher host infection prevalence. Snake species identity further influenced infection, with most positive detections coming from the Natrix genus. Most species present in the community only experienced increased levels of infection when multiple strains were present. However, one species, N. tessellata , appeared highly susceptible, having increased infection prevalence regardless of pathogen strain, indicating that this species may be important in pathogen maintenance.
4. Our results suggest that both host and pathogen identity are essential components contributing to increased pathogen prevalence. More broadly, our findings indicate that coevolutionary relationships between hosts and pathogens may be key mechanisms explaining variation in landscape patterns of disease.
Fungi are an understudied resource possessing huge potential for developing products that can greatly improve human well-being. In the current paper, we highlight some important discoveries and developments in applied mycology and interdisciplinary Life Science research. These examples concern recently introduced drugs for the treatment of infections and neurological diseases; application of –OMICS techniques and genetic tools in medical mycology and the regulation of mycotoxin production; as well as some highlights of mushroom cultivaton in Asia. Examples for new diagnostic tools
in medical mycology and the exploitation of new candidates for therapeutic drugs, are also given. In addition, two entries illustrating the latest developments in the use of fungi for biodegradation and fungal biomaterial production are provided.
Some other areas where there have been and/or will be significant developments are also included. It is our hope that this paper will help realise the importance of fungi as a potential industrial resource and see the next two decades bring forward
many new fungal and fungus-derived products.
Snake fungal disease (SFD; ophidiomycosis), caused by the pathogen Ophidiomyces ophiodiicola (Oo), has been documented in wild snakes in North America and Eurasia, and is considered an emerging disease in the eastern United States of America. However, a lack of historical disease data has made it challenging to determine whether Oo is a recent arrival to the USA or whether SFD emergence is due to other factors. Here, we examined the genomes of 82 Oo strains to determine the pathogen’s history in the eastern USA. Oo strains from the USA formed a clade (Clade II) distinct from European strains (Clade I), and molecular dating indicated that these clades diverged too recently (approximately 2,000 years ago) for transcontinental dispersal of Oo to have occurred via natural snake movements across Beringia. A lack of nonrecombinant intermediates between clonal lineages in Clade II indicates that Oo has actually been introduced multiple times to North America from an unsampled source population, and molecular dating indicates that several of these introductions occurred within the last few hundred years. Molecular dating also indicated that the most common Clade II clonal lineages have expanded recently in the USA, with time of most recent common ancestor mean estimates ranging from 1985 to 2007 CE. The presence of Clade II in captive snakes worldwide demonstrates a potential mechanism of introduction and highlights that additional incursions are likely unless action is taken to reduce the risk of pathogen translocation and spillover into wild snake populations.
There is growing concern about infectious diseases in wildlife species caused by pathogenic fungi. Detailed knowledge exists about host pathology and the molecular mechanisms underlying host physiological response to some fungal diseases affecting amphibians and bats but is lacking for others with potentially significant impacts on large groups of animals. One such disease is ophidiomycosis (Snake Fungal Disease; SFD) which is caused by the fungus Ophidiomyces ophidiicola and impacts diverse species of snakes. Despite this potential, the biological mechanisms and molecular changes occurring during infection are unknown for any snake species. To gain this information, we performed a controlled experimental infection of captive Prairie rattlesnakes ( Crotalus viridis ) with O. ophidiicola at different temperatures. We then generated liver, kidney, and skin transcriptomes from control and infected snakes to assess tissue specific genetic responses to infection. Given previous SFD histopathological studies and the fact that snakes are ectotherms, we expected highest fungal activity on skin and a significant impact of temperature on host response. In contrast, we found that most of the differential gene expression was restricted to internal tissues and fungal-infected snakes showed transcriptome profiles indicative of long-term inflammation of specific tissues. Infected snakes at the lower temperature had the most pronounced overall host functional response whereas, infected snakes at the higher temperature had overall expression profiles similar to control snakes possibly indicating recovery from the disease. Overall, our results suggest SFD is a systemic disease with a chronic host response, unlike acute response shown by amphibians to Batrachochytrium dendrobatidis infections. Our analysis also generated a list of candidate protein coding genes that potentially mediate SFD response in snakes, providing tools for future comparative and evolutionary studies into variable species susceptibility to ophidiomycosis.
Author summary
Ophidiomycosis (Snake Fungal Disease; SFD) is an infectious fungal disease in snakes that has been documented in more than 40 species over the past 20 years. Though many snake species seem vulnerable to SFD, little is known about how snake physiology changes in response to infection with the causative fungus, Ophidiomyces ophidiicola . Here we report results from the first experimental transcriptomic study of SFD in a snake host. Our goals were to identify genes with a putative role in host response, use this information to understand what biological changes occur in different tissues in snakes when infected with O. ophidiicola , and determine if temperature has an impact in these ectothermic animals. We conclude that SFD is a systemic disease with a chronic inflammation leading to deterioration of internal organs and that these physiological impacts are more pronounced at low rather than high temperatures. These results contrast with fungal infections in amphibians where hosts show an acute response mostly restricted to skin. Our list of candidate genes carry utility in potentially diagnosing genetic susceptibility to SFD in snake species of conservation concern.
Habitat loss, human persecution, and infectious diseases all threaten declining reptile populations. Lake Erie watersnakes (Nerodia sipedon insularum, LEWS), once classified as an endangered species in part due to human persecution, have recovered to stable population levels but have been observed with a high prevalence of ophidiomycosis. Strategies are needed to mitigate the current disease threat, including assessing overall wellness. Hematologic analysis provides information about the presence of inflammation and infection and thus informs health-based conservation efforts, but has not been previously performed in LEWS. The objective of this study was to evaluate hematologic parameters in LEWS and identify differences based on ophidiomycosis status. Blood was drawn from wild-caught snakes at nine sites in 2018 and 2019 and complete blood counts were performed in 180 individuals. For apparently healthy snakes, packed cell volume was significantly higher in males (median = 32.5%) compared to females (median = 26.5%; P = 0.03). Animals classified as having possible or apparent ophidiomycosis, or those with skin lesions, had a relative azurophilia and lymphopenia compared to individuals classified as negative or Ophidiomyces present, or those without skin lesions (P < 0.01). This is the first study to investigate hematology in a free-ranging population of LEWS and will serve as a baseline for future investigations that aim to improve conservation efforts through population health monitoring.
The aim of this work was to identify the lipase activity of Sporothrix schenckii strains using Rhodamine B as an indicator oftriglyceride hydrolysis (triolein from olive oil) and to compare these results with the use of Tween 80 as substrate. Free fatty acidsreleased from lipase activity were detected on agar plate complexed with Rhodamine B, when exposed to UVA light, through orangefluorescence and by precipitation haloes on Tween 80 agar. There were differences in lipolytic activity among strains and between themedia utilized. The highest lipase activity (orange fluorescence) was observed on the biomass of 10 strains, with no fluorescent haloesaround the colonies, whereas only six strains showed large precipitation haloes. These plate assays are suitable for the detection oflipase-producing strains of S. schenckii in the yeast phase, but it is still unknown whether different enzymes act upon the substrates orwhether there are variations of the same enzyme with different specificities.
Manganese (Mn) oxidation was evaluated for Petri disease fungi by using potato dextrose agar (PDA)
amended with Mn sulfate. Phaeomoniella chlamydospora showed reduced growth on PDA amended with 3000 ppm
Mn sulfate and exhibited no growth at higher concentrations. All Phaeoacremonium spp. evaluated were manganese
tolerant and grew on PDA amended with as much as 6000 ppm Mn sulfate. Phaeoacremonium viticola and P. angustius
s.s. oxidized manganese in vitro. Stereum hirsutum and Fomitiporia punctata, known white-rot basidiomycetes,
were used as controls. Stereum hirsutum oxidized Mn in vitro and grew on PDA amended with 6000 ppm Mn sulfate.
Fomitiporia punctata had reduced growth at 300 ppm and no growth at higher concentrations of Mn sulfate with no
clear evidence of Mn oxidation.
A free-ranging plains garter snake (Thamnophis radix) with a brown, encrusted, cutaneous facial lesion presented depressed, emaciated, and dehydrated. It developed respiratory distress and was later euthanized after it failed to respond to antibiotics and supportive treatment. Disseminated granulo-matous disease with prominent lung involvement was diagnosed at necropsy. Intralesional hyaline fungal elements, consisting of septate hyphae, were detected histologically among the necrotic core of granulomas and aggregates of epithelioid macrophages. Ophidiomyces ophiodiicola was cultured from tissue specimens and identification was confirmed using 18S rRNA ITS DNA sequencing. Isolation of O. ophiodiicola from lesions that contain morphologically consistent fungal elements strongly incriminates this fungus as the cause of disease in this garter snake.
Fungal pathogens threatening the conservation of wildlife are becoming increasingly common. Since 2008, free-ranging snakes across North America have been experiencing a marked increase in the prevalence of snake fungal disease associated with Ophidiomyces ophiodiicola. Diagnosis has historically relied on histology, microbiology, and conventional polymerase chain reaction (PCR). More sensitive methods are needed to adequately characterize the epidemiology. The current study describes the development of a real-time PCR (qPCR) assay for detecting a segment of the internal transcribed spacer 1 region between the 18S and 5.8S ribosomal RNA gene. The assay was able to detect as few as 1.05 × 10(1) gene copies per reaction. An additional 4 positive cases were detected when comparing a conventional PCR (n = 3) and the qPCR (n = 7) when used on swab samples from 47 eastern massasauga rattlesnakes. The newly developed assay is a sensitive and specific tool for surveillance and monitoring in the conservation of free-ranging snakes.
© 2015 The Author(s).
Pseudogymnoascus destructans, the causal agent of bat white-nose syndrome, has caused nearly six million deaths in North American bats since its introduction into the United States in 2006. Current research has shown that caves can harbor P. destructans even after the infected bats are removed and bats no longer visit or inhabit previously infected caves. Our research focuses on elucidating reservoir requirements by investigating the nutritional capabilities of and substrate suitability requirements for six different P. destructans isolates from various localities including Illinois, Indiana, New York (Type specimen), and Pennsylvania. Enzyme assays implicate that both urease and b-glucosidase appear to be constitutive, lipase and esterase activity were more rapid than proteinase activity on 6% gelatin, gelatin degradation was accompanied by medium alkalinization, the reduction of thiosulfate generated hydrogen sulfide gas, chitinase and manganese dependent peroxidase activity were not visually demonstrated within eight weeks, and keratinase activity was not evident at pH 8 within eight weeks. We demonstrate that all P. destructans isolates are capable of growth and sporulation on dead fish, insect, and mushroom tissues. Sole nitrogen source assays demonstrated that all P. destructans isolates exhibit Class 2 nitrogen utilization and that growth-dependent interactions occur among different pH and nitrogen sources. Substrate suitability assays demonstrated that all isolates could grow and sporulate on media ranging from pH 5-11 and tolerated media supplemented with 2000 mg/L of calcium and 700 mg/L of three separated sulfur compounds: thiosulfate L-cysteine, and sulfite. All isolates were intolerant to PEG-induced matric potential with delayed germination and growth at -2.5 MPa with no visible germination at -5 MPa. Interestingly, decreasing the surface tension with Tween 80 permitted germination and growth of P. destructans in -5 MPa PEG medium within 14 days suggesting a link between substrate suitability and aqueous surface tension altering substances.
In recent years, the Chrysosporium anamorph of Nannizziopsis vriesii (CANV), Chrysosporium guarroi, Chrysosporium ophiodiicola, and Chrysosporium species have been reported as the causes of dermal or deep lesions in reptiles. These infections are contagious and often
fatal and affect both captive and wild animals. Forty-nine CANV isolates from reptiles and six isolates from human sources
were compared with N. vriesii based on their cultural characteristics and DNA sequence data. Analyses of the sequences of the internal transcribed spacer
and small subunit of the nuclear ribosomal gene revealed that the reptile pathogens and human isolates belong in well-supported
clades corresponding to three lineages that are distinct from all other taxa within the family Onygenaceae of the order Onygenales. One lineage represents the genus Nannizziopsis and comprises N. vriesii, N. guarroi, and six additional species encompassing isolates from chameleons and geckos, crocodiles, agamid and iguanid lizards, and
humans. Two other lineages comprise the genus Ophidiomyces, with the species Ophidiomyces ophiodiicola occurring only in snakes, and Paranannizziopsis gen. nov., with three new species infecting squamates and tuataras. The newly described species are Nannizziopsis dermatitidis, Nannizziopsis crocodili, Nannizziopsis barbata, Nannizziopsis infrequens, Nannizziopsis hominis, Nannizziopsis obscura, Paranannizziopsis australasiensis, Paranannizziopsis californiensis, and Paranannizziopsis crustacea. Chrysosporium longisporum has been reclassified as Paranannizziopsis longispora. N. guarroi causes yellow fungus disease, a common infection in bearded dragons and green iguanas, and O. ophiodiicola is an emerging pathogen of captive and wild snakes. Human-associated species were not recovered from reptiles, and reptile-associated
species were recovered only from reptiles, thereby mitigating concerns related to zoonosis.
The effect of water potential and temperature on growth and cellulolysis of 10 soil fungi which colonize cereal crop residues was determined in vitro. On 2% (w/v) milled straw agar all species grew in the range -0.7 to -7.0 MPa at both 10 and 20 °C. Growth rates differed depending on the solute type used to control water potential. In general, but with the exception of the Penicillium spp., growth decreased with decreasing water potential. Hyphal growth on sterile straw internode segments was much less than that on 2% straw agar. Fusarium culmorum and Trichoderma harzianum colonized straw pieces best at high potential (-0.7 MPa) while only F. culmorum and the Penicillium spp. grew at low potential (-7.0 MPa). Trichoderma spp., Gliocladium spp. and Chaetomium globosum cleared cellulose agar most rapidly, depth of clearing decreasing with water potential in the range -0.7 to -2.8 MPa at 20 ° C. The relationship between dry weight loss of inoculated cellulose filter paper and water potential was more variable.
Although temperate zone snakes spend a large part of each year in hibernation, we know relatively little about their behavior during this part of the annual cycle. We used radiotelemetry to monitor temperatures and movements of hibernating rattlesnakes (Crotalus viridis) in southern British Columbia and garter snakes (Thamnophis sirtalis) in northern Alberta, and measured thermal profiles inside their hibernacula. A reference site near the garter snake hibernaculum, superficially resembling a winter den but not used by snakes, also was monitored. A thermal gradient (temperature increasing with depth) formed during the winter in the rattlesnake den, but only minimally so in the garter snake den. Differences in thermal profiles were attributed to differences in subsurface geomorphology. The reference site exhibited much greater temperature fluctuation than the den itself, with lethal temperatures prevailing throughout the winter. Therefore, suitable hibernation sites may be limited in some areas despite a superficial appearance of abundance. As ambient temperatures declined during early winter, snakes made lateral movements inside their hibernacula, and exhibited changes in body temperature which we interpreted as movements to warmer (deeper) microsites. Body temperatures recorded during winter ranged between 2 and 7 °C. In early spring the thermal gradient collapsed and the rattlesnake den gradually underwent a uniform increase in temperature. A similar increase in subterranean temperatures occurred in the garter snake den. Temperature change was perhaps a stimulus for emergence in rattlesnakes, but possibly not in garter snakes. The hypothesis that hibernating snakes orient along a seasonally reversing thermal gradient is not unambiguously supported.
With the current rate of declines in global biodiversity, it is apparent that wildlife diseases are serving as additional threats to population declines and potentially species extinctions. Free-ranging Eastern Massasaugas (Sistrurus catenatus catenatus) have been reported susceptible to numerous health threats, one of which is a fatal fungal dermatitis. In response to the occurrence of the fungal dermatitis, a health survey and disease investigation was conducted on Eastern Massasaugas near Carlyle, Illinois in 2011. We captured 38 Eastern Massasaugas from March to April 2011. Polymerase chain reaction assays were performed from swabs collected from the faces of 34 snakes. We obtained hematologic data for 31 individuals, plasma biochemical data for 24, and toxicological data for 18. There was no evidence of Chrysosporium in any of the samples. Hematologic and plasma biochemistry parameters were consistent with previous health studies in the Carlyle population. Elemental toxicologic investigation of the plasma indicated variable levels of lead, copper, selenium, strontium, tin, iron, and zinc.
a b s t r a c t Extinction of populations from anthropogenic forces rarely has a single cause. Instead, population declines result from a variety of factors, including habitat loss, inbreeding depression, disease, and cli-mate change. These impacts often have synergistic effects that can lead to rapid decline in isolated pop-ulations, but case studies documenting such processes are rare. Here, we describe the recent decline of the last known population of timber rattlesnakes (Crotalus horridus) in the state of New Hampshire. We used polymorphic nuclear DNA markers to compare genetic diversity of this population to other pop-ulations in the region that are not isolated. We also compare results from ongoing field monitoring of these populations. Genetic analyses reveal that the New Hampshire population lacks genetic diversity and exhibits signs of a recent bottleneck. New Hampshire snakes also exhibited high levels of morpho-logical abnormalities (unique piebald coloration, amelanistic tongues) indicative of inbreeding depres-sion. Furthermore, after a year with exceptionally high summer rainfall, a skin infection of unknown etiology caused significant mortality in the New Hampshire population, whereas other surveyed non-inbred populations were unaffected. This case study demonstrates how different anthropogenic impacts on natural environments can interact in unexpected ways to drive threatened populations toward extinction.
Pointing S.B. (1999). Qualitative methods for the determination of lignocellulolytic enzyme production by tropical fungi. Fungal Diversity 2: 17-33. A range of qualitative approaches to the assessment of lignocellulose degrading' enzyme production are presented, with detailed stepwise methodology for each assay. The advantages, variations and limitations to each method are discussed. Recommendations for the use of these procedures in achieving specific research objectives are given. Introduction There is considerable research effort on the biodiversity, ecology and economic importance of tropical fungi (Hyde, 1997). This includes systematic studies and the screening of fungal isolates for bioactive compounds. Most isolates are from lignocellulose substrates such as wood, grasses, palms and seeds. There is significant interest in the enzymes responsible for lignocellulose degradation in terms of understanding their ecological role, also in the biotechnology potential of enzymes involved in this process (Reddy, 1995). Lignocellulose is a heteropolymer consisting mainly of three components, cellulose, hemicellulose and lignin (Fengel and Wegener, 1989; Eaton and Hale, 1993). The characteristics of these components are summarised, with the major enzymes responsible for their degradation in Table 1. For recent reviews on lignocellulose degrading enzymes see Eaton and Hale (1993), Reddy and D'Souza (1994) and Thurston (1994). Qualitative assays are powerful tools used in screening fungi for lignocellulose degrading enzyme production. Such tests give a positive or negative indication of enzyme production. They are particularly useful in screening large numbers of fungal isolates for several classes of enzyme, where definitive quantitative data are not required. The reagents required are all 17 commonly available and relatively inexpensive. In addition the methodology is straightforward and so assays can be carried out by mycologists with little specialized knowledge of enzymology. A major drawback in qualitative assays has been the lack of any standardized methodology. Numerous reports in the literature have employed qualitative assays, however many of these studies have used very different protocols. The results range from those with suspect or meaningless data to some excellent findings. Comparison of results between such studies is virtually impossible. The purpose of this paper is to review qualitative methods and suggest standard protocols for assay of the major lignocellulose degrading enzymes. The advantages, variations and limitations to each method are also discussed. The procedures are conveniently grouped into cellulolytic, hemicellulolytic (although in practice xylan is the only substrate used in such assays) and lignin modifying enzyme assays. This is considered the most comprehensive publication to date on qualitative enzyme assay methodology and is primarily intended for use with tropical fungi. The procedures can be adapted for use with marine fungi by adding appropriate concentrations of marine salts. Incubation time and temperature may be adjusted to suit temperate or slow growing strains if necessary. Table 1. The major components of lignocellulose and fungal enzymes involved in their degradation.
The global emergence and spread of the pathogenic, virulent, and highly transmissible fungus Batrachochytrium dendrobatidis, resulting in the disease chytridiomycosis, has caused the decline or extinction of up to about 200 species of frogs. Key
postulates for this theory have been completely or partially fulfilled. In the absence of supportive evidence for alternative
theories despite decades of research, it is important for the scientific community and conservation agencies to recognize
and manage the threat of chytridiomycosis to remaining species of frogs, especially those that are naive to the pathogen.
The impact of chytridiomycosis on frogs is the most spectacular loss of vertebrate biodiversity due to disease in recorded
history.
The past two decades have seen an increasing number of virulent infectious diseases in natural populations and managed landscapes. In both animals and plants, an unprecedented number of fungal and fungal-like diseases have recently caused some of the most severe die-offs and extinctions ever witnessed in wild species, and are jeopardizing food security. Human activity is intensifying fungal disease dispersal by modifying natural environments and thus creating new opportunities for evolution. We argue that nascent fungal infections will cause increasing attrition of biodiversity, with wider implications for human and ecosystem health, unless steps are taken to tighten biosecurity worldwide.
Screening methods for the isolation of alkaline lipase producing fungi (acylglycerol hydrolases) from aged and crude rice bran oil and quantification of the Free Fatty Acid liberated (FFA) by the enzyme using HPTLC is discussed. Screening using rhodamine B detected lipase production as an orange halo around microbial colonies under UV light at 350 nm. Chromogenic plates incorporated with a lipidic substrate along with phenol red showed a sharp change in color from pink to yellow due to the presence of liberated fatty acids which was also an indication of lipase production. Media having pH in the range of 8.5 to 10.5 along with tributyrin substrate was used for screening an alkaline lipase producing isolate. The hydrolysis of tween opacity medium and production of an opaque halo in alkaline tributyrin agar plates confirmed the production of alkaline lipase by the isolated organism. The isolated fungus was identified as Aspergillus fumigatus MTCC 9657 from IMTECH, Chandigarh. There is no much information of alkaline lipase production by A fumigatus isolated from aged rice bran oil. Positional specificity of the isolated lipase was determined to be non specific by TLC and FTIR. Quantification of lipase activity of A fumigatus was carried out with the aid of High Performance Thin-layer Chromatography (HPTLC) which can detect even micro quantities of FFA produced and are rapid, efficient and easy-to use for simultaneous analysis.
TO THE EDITOR: During 2008, the ninth year of a long-term biologic monitoring program, 3 eastern massasauga rattlesnakes (Sistrurus catenatus catenatus) with severe facial swelling and disfiguration died within 3 weeks after discovery near Carlyle, Illinois, USA. In spring 2010, a similar syndrome was diagnosed in a fourth massasauga; this snake continues to be treated with thermal and nutritional support and antifungal therapy. A keratinophilic fungal infection caused by Chrysosporium sp. was diagnosed after physical examination, histopathologic analysis, and PCR in all 4 snakes. The prevalence of clinical signs consistent with Chrysosporium sp. infection during 2000-2007 was 0.0%, and prevalence of Chrysosporium sp.-associated disease was 4.4% (95% confidence interval [CI] 1.1%-13.2%) for 2008 and 1.8% (95% CI 0.0%-11.1%) for 2010.
Infectious diseases are increasingly recognized as the cause of mass mortality events, population declines, and the local extirpation of wildlife species. In a number of cases, it has been hypothesized that pathogens have caused species extinctions in wildlife. However, there is only one definitively proven case of extinction by infection, and this was in a remnant captive population of a Polynesian tree snail. In this article, we review the potential involvement of infectious disease in the recent extinction of the sharp-snouted day frog Taudactylus acutirostris. Our review of available evidence suggests that a virulent pathogen of amphibians, Batrachochytrium dendrobatidis, caused a rapid, catastrophic decline of this species, from which it did not recover. We propose that this is the first case of extinction by infection of a free-ranging wildlife species where disease acted as both the proximate and ultimate cause of extinction. This highlights a probable underreporting of infectious disease as a cause of biodiversity loss historically and currently. Yes Yes
Isolation and characterization of the new species Chrysosporium ophiodiicola from a mycotic granuloma of a black rat snake (Elaphe obsoleta obsoleta) are reported. Analysis of the sequences of different fragments of the ribosomal genes demonstrated that this species belongs
to the Onygenales and that this species is genetically different from other morphologically similar species of Chrysosporium. This new species is unique in having both narrow and cylindrical-to-slightly clavate conidia and a strong, pungent odor.
White-nose syndrome (WNS) is a condition associated with an unprecedented bat mortality event in the northeastern United States. Since the winter of 2006*2007, bat declines exceeding 75% have been observed at surveyed hibernacula. Affected bats often present with visually striking white fungal growth on their muzzles, ears, and/or wing membranes. Direct microscopy and culture analyses demonstrated that the skin of WNS-affected bats is colonized by a psychrophilic fungus that is phylogenetically related to Geomyces spp. but with a conidial morphology distinct from characterized members of this genus. This report characterizes the cutaneous fungal infection associated with WNS.
Necrotizing mycotic dermatitis was diagnosed in 6 snakes. Cutaneous lesions involved ventral and lateral scales. Each clinical diagnosis was confirmed by fungal culture and light microscopic evaluation of biopsied scales. The differential clinical considerations included contact dermatitis and bacterial dermatitis.
Cutaneous fungal infections occurred in four captive brown tree snakes (Boiga irregularis). The ventral scales were most commonly affected, and lesions began as areas of erythema and edema with vesicle formation, followed by development of caseous brown plaques. Lesions usually started where ventral scales overlapped and spread rapidly. All snakes died within 14 days after clinical signs were first noted. The deaths of three of the snakes were directly attributable to the cutaneous disease; the other snake died from renal failure and visceral gout, most likely induced by gentamicin therapy. Histologically, lesions consisted of epidermal hyperplasia and hyperkeratosis, with foci of epidermal necrosis, intraepidermal vesicle formation, and subacute inflammation of the underlying dermis. These lesions were associated with bacteria and numerous septate, branched fungal hyphae within the epidermis and overlying serocelluar crusts. Hyphae that penetrated through the superficial surface of the epidermis often formed terminal arthroconidia. The same species of fungus was isolated in pure culture from the skin of three snakes, but fungal cultures were not performed on samples from the fourth snake. The fungus has been identified as the Chrysosporium anamorph of Nannizziopsis vriesii based on its formation of solitary dermatophytelike aleurioconidia and alternate and fission arthroconidia. The source of the fungus in this outbreak was not determined; however, the warm, moist conditions under which the snakes were housed likely predisposed them to opportunistic cutaneous fungal infections.
Emerging infectious diseases (EIDs) of free-living wild animals can be classified into three major groups on the basis of
key epizootiological criteria: (i) EIDs associated with “spill-over” from domestic animals to wildlife populations living
in proximity; (ii) EIDs related directly to human intervention, via host or parasite translocations; and (iii) EIDs with no
overt human or domestic animal involvement. These phenomena have two major biological implications: first, many wildlife species
are reservoirs of pathogens that threaten domestic animal and human health; second, wildlife EIDs pose a substantial threat
to the conservation of global biodiversity.
Between September 1997 and March 1998, a severe skin, eye, and mouth disease was observed in a population of dusky pigmy rattlesnakes (Sistrurus miliarius barbouri), at the Lake Woodruff National Wildlife Refuge in Volusia County, Florida (USA). Three affected pigmy rattlesnakes were submitted for necropsy. All snakes had severe necrotizing and predominantly granulomatous dermatitis, stomatitis, and ophthalmitis, with involvement of the subadjacent musculature and other soft tissues. Numerous fungal hyphae were seen throughout tissue sections stained with periodic acid Schiff and Gomori's methenamine silver. Samples of lesions were cultured for bacteria and fungi. Based on hyphae and spore characteristics, four species of fungi were identified from culture: Sporothrix schenckii, Pestalotia pezizoides, Geotrichum candidum (Galactomyces geotrichum), and Paecilomyces sp. While no additional severely affected pigmy rattlesnakes were seen at the study site, a garter snake (Thamnophis sirtalis) and a ribbon snake (Thamnophis sauritis) with similar lesions were found. In 1998 and 1999, 42 pigmy rattlesnakes with multifocal minimal to moderate subcutaneous masses were seen at the study site. Masses from six of these snakes were biopsied in the field. Hyphae morphologically similar to those seen in the severe cases were observed with fungal stains. Analysis of a database representing 10,727 captures in previous years was performed after the 1998 outbreak was recognized. From this analysis we determined that 59 snakes with clinical signs similar to those seen during the 1998 outbreak were documented between 1992 and 1997. This study represents the first documented report of a mycotic disease of free-ranging snakes.
The fungus Chrysosporium anamorph of Nannizziopsis vriesii was identified as the cause of fatal, multifocal, heterophilic dermatitis in four freshwater aquatic captive-bred tentacled snakes (Erpeton tentaculatum). Pale, 1- to 4-mm focal lesions involving individual scales, occurred primarily on the head and dorsum. Histology showed multifocal coagulation necrosis of the epidermis, with marked heterophilic infiltration without involvement of the underlying dermis. Septate, irregularly branched hyphae, and clusters of 4- to 8- by 2- to 3-microm rod-shaped cells (arthroconidia) were present within the lesions and in a superficial crust. Failure to maintain an acidic environment was likely a predisposing factor in the development of these lesions.
The rate and amount of growth of twenty-five species of fungi were determined when they were supplied with nitrate, ammonium, and organic (asparagine) nitrogen. Nitrate nitrogen was used slowly by some of the Basidiomycetes tested and poorly, if at all, by others. From the standpoint of rapidity and amount of mycelium produced, asparagine and ammonium sulfate supplemented with fumaric acid were about equal in value and superior to either ammonium sulfate or potassium nitrate. Fumarate had little if any effect on the utilization of nitrate nitrogen.
The authors formally investigated a major international wildlife wholesaler and subsequently confiscated more than 26,400 nonhuman animals of 171 species and types. Approximately 80% of the nonhuman animals were identified as grossly sick, injured, or dead, with the remaining in suspected suboptimal condition. Almost 3,500 deceased or moribund animals (12% of stock), mostly reptiles, were being discarded on a weekly basis. Mortality during the 6-week "stock turnover" period was determined to be 72%. During a 10-day period after confiscation, mortality rates (including euthanasia for humane reasons) for the various taxa were 18% for invertebrates, 44.5% for amphibians, 41.6% for reptiles, and 5.5% for mammals. Causes of morbidity and mortality included cannibalism, crushing, dehydration, emaciation, hypothermic stress, infection, parasite infestation, starvation, overcrowding, stress/injuries, euthanasia on compassionate grounds, and undetermined causes. Contributing factors for disease and injury included poor hygiene; inadequate, unreliable, or inappropriate provision of food, water, heat, and humidity; presumed high levels of stress due to inappropriate housing leading to intraspecific aggression; absent or minimal environmental enrichment; and crowding. Risks for introduction of invasive species through escapes and/or spread of pathogens to naive populations also were identified.
The lithium battery using Fe3O4 fine particles has been constructed. The discharge characteristics were improved by the addition of India ink or polyvinyl alcohol (PVA). The discharge potential at 60°C maintained 2.5V versus Li/Li+ up to 500mAhg−1 and was 1.8V at a large capacity of 926mAhg−1. The possibility of secondary battery was discussed from the result of cycling test with 926mAhg−1. Similar potential curve was obtained in the second cycle. Although degradation was observed in the third cycle, cyclability was maintained. However, the test cell stopped in fourth discharge. It is concluded that a large capacity was achieved at 60°C using fine particles of Fe3O4 with PVA additive. According to the cycling test, it is expected to be a secondary battery by further development in nanostructure of the cathode.
The effects of water activity (aw, 0.994–0.90 ≡ 0.4–14.0 (–)MPa water potential), temperature (4–45 °C), and pH (3.6, 5.5, 7.0), and their interactions on growth of isolates of Fusarium moniliforme and Fusarium proliferatum were determined in vitro on a maize extract agar medium. Growth of two isolates of F. moniliforme and four isolates of F. proliferatum were significantly influenced by water activity regardless of solute type used (NaCl, glycerol, or glucose). However, at steady-state aw levels, growth was optimum at 0.994–0.98 aw and reduced significantly at 0.92 aw. Further detailed studies with one isolate of F. moniliforme (25N) and two isolates of F. proliferatum (73N, 13 IN) showed that growth occurred over the range of 0.994–0.90 aw in the temperature range 20–35 °C with slight differences between species. Growth did occur at 4 °C and 0.994–0.96 aw, but no growth was recorded at 40 and 45 °C regardless of aw. Profiles of aw × temperature relations for growth of these two species were constructed from these data for the first time. Optimum pH and temperature for growth was 5.5 and 25 °C for both isolates of F. proliferatum, and pH 7.0 and 30 °C for the isolate of F. moniliforme. However, for the latter isolate at <0.98 aw, optimum pH and temperature for growth changed. The effects of pH, temperature, and aw for single, two-way and three-way interactions were all found to be statistically significant for these three isolates. The ecological significance of this information for understanding these important fumonisin-producing fungi is discussed.Key words: water activity, temperature, fumonisin-producing, Fusarium moniliforme, Fusarium proliferatum, maize.
The ubiquity, high diversity and often-cryptic manifestations of fungi and oomycetes frequently necessitate molecular tools for detecting and identifying them in the environment. In applications including DNA barcoding, pathogen detection from plant samples, and genotyping for population genetics and epidemiology, rapid and dependable DNA extraction methods scalable from one to hundreds of samples are desirable. We evaluated several rapid extraction methods (NaOH, Rapid one-step extraction (ROSE), Chelex 100, proteinase K) for their ability to obtain DNA of quantity and quality suitable for the following applications: PCR amplification of the multicopy barcoding locus ITS1/5.8S/ITS2 from various fungal cultures and sporocarps; single-copy microsatellite amplification from cultures of the phytopathogenic oomycete Phytophthora ramorum; probe-based P. ramorum detection from leaves. Several methods were effective for most of the applications, with NaOH extraction favored in terms of success rate, cost, speed and simplicity. Frozen dilutions of ROSE and NaOH extracts maintained PCR viability for over 32 months. DNA from rapid extractions performed poorly compared to CTAB/phenol-chloroform extracts for TaqMan diagnostics from tanoak leaves, suggesting that incomplete removal of PCR inhibitors is an issue for sensitive diagnostic procedures, especially from plants with recalcitrant leaf chemistry. NaOH extracts exhibited lower yield and size than CTAB/phenol-chloroform extracts; however, NaOH extraction facilitated obtaining clean sequence data from sporocarps contaminated by other fungi, perhaps due to dilution resulting from low DNA yield. We conclude that conventional extractions are often unnecessary for routine DNA sequencing or genotyping of fungi and oomycetes, and recommend simpler strategies where source materials and intended applications warrant such use.
A male garter snake (Thamnophis) from a private terrarium was spontaneously and simultaneously infected with Chrysosporium queenslandicum and Geotrichum candidum. The autopsy revealed disseminated mycotic alterations in skin, lungs and liver. Chrysosporium queenslandicum grew well at 28 °C, the optimal temperature of the animal. This is the first description of a Chrysosporium queenslandicum infection in a garter snake.
Huge amounts of alkaline enzymes are used in the detergent industry, and they have been widely incorporated into heavy-duty laundry and automatic dishwashing detergents. The alkaline enzymes used in modern detergents are protease, cellulase, α-amylase, lipase, and mannanase. In this chapter, methods for screening alkaline enzyme-producing alkaliphilic Bacillus strains, enzyme assays, purification, properties, and genetics of enzymes are described.
Key WordsSerine protease–subtilisin–cellulase–endoglucanase–α-amylase–pectinase–lipase–mannanase–alkaliphile–Bacillus–laundry detergent–dishwashing detergent
In a series of studies on the distribution of alkalophilic and alkali-tolerant fungi, soil fungi were isolated from five alkaline
calcareous soil samples in two closely located limestone caves (stalactite caves) in Japan using slightly acidic and alkaline
media. Some common soil fungi that can grow in alkaline conditions were obtained in high frequencies. The growth response
to pH of the isolates revealed that approximately one third (30.8%) of the isolates had the optimum pH in the alkaline range.
All isolates of fourAcremonium species and twoChrysosporium species grew well in alkaline conditions, of whichAcremonium sp. andChrysosporium sp. were pronounced alkalophiles. These fungi were thought to be indigenous species in this alkaline environment. The fungal
flora in the Japanese alkaline soils was considerably different from the flora reported in alkaline environments in other
countries.
The chemical composition of shrimp shells from the deep-water shrimp (Pandalus borealis) obtained from a local factory in northern Norway that were harvested from January to December (2000) in the Barents Sea was investigated. The average dry matter content of the samples of shrimp shells was 22 ± 2%, with no significant seasonal variation. The protein content was found to vary between 33% and 40% of the dry weight, the chitin content varied between 17% and 20% and the ash content of dried shrimp shells was found to be relatively constant with an average value of 34 ± 2% of the dry weight and consisting mainly of calcium carbonate (CaCO3). No clear seasonal variations were found for the content of these three main components of shrimp shells (protein, chitin and ash). The shrimp shells had a very low lipid content, varying from 0.3% to 0.5% of the dry weight. The content of astaxanthin was found to vary from 14 to 39 mg kg−1 in the samples of wet shrimp shells. In relation to its use as a raw material for chitin production, no clear seasonal variation was found in the intrinsic viscosities/molecular weights of the chitin extracted from the shrimp shells using an optimized extraction procedure for chitin extraction, suggesting that chitin producers can rely on shrimp shell waste as a stable raw material for chitin production independent of season.
Environmental pathogenic fungi present a paradox in that they are virulent in animals without requiring animal hosts for replication or survival, a phenomenon we call 'ready-made' virulence. In the human pathogenic fungus Cryptococcus neoformans, the capacity for virulence in animals may originate from environmental selective pressures imposed by such organisms as amoeboid and nematode predators. Many C. neoformans virulence factors appear to have 'dual use' capabilities that confer survival advantages in both animal hosts and in the environment. The findings with C. neoformans may provide a paradigm for understanding the origin and maintenance of virulence in other pathogenic environmental fungi.
Published and additional data for polyethylene glycol 8000 (PEG), formerly PEG 6000, solution water potentials (Psi) are compared. Actual bars Psi over the concentration range of 0 to 0.8 gram PEG per gram H(2)O and temperature (T) range of 5 to 40 degrees C are best predicted (probably within +/- 5%) by this equation: Psi = 1.29[PEG](2)T - 140[PEG](2) - 4.0[PEG]. Although transformable through division by [PEG] to virial equation form, results indicate that the coefficients are not virial. Mannitol (MAN) interacts with PEG to produce Psi significantly lower than additive. Vapor pressure osmometer (VPO) data for MAN-PEG synergism compared favorably with those from thermocouple hygrometry; and VPO data showing the interactions between PEG and four salts are presented. The synergism of MAN-PEG and of NaCl-PEG are related linearly to the concentration of solute added with PEG.
First report of snake fungal disease from Michigan
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Studies on the distribution of alkalophilic and alkali-tolerant soil fungi II: fungal flora in two limestone caves in Japan. Mycoscience 39, 293e298
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An unusual mortality event associated with Chrysosporium in eastern massasauga rattlesnakes (Sistrurus catenatus catenatus)
- Allender