Article

The role of infectious diseases in biological conservation

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Abstract

Recent increases in the magnitude and rate of environmental change, including habitat loss, climate change and overexploitation, have been directly linked to the global loss of biodiversity. Wildlife extinction rates are estimated to be 100–1000 times greater than the historical norm, and up to 50% of higher taxonomic groups are critically endangered. While many types of environmental changes threaten the survival of species all over the planet, infectious disease has rarely been cited as the primary cause of global species extinctions. There is substantial evidence, however, that diseases can greatly impact local species populations by causing temporary or permanent declines in abundance. More importantly, pathogens can interact with other driving factors, such as habitat loss, climate change, overexploitation, invasive species and environmental pollution to contribute to local and global extinctions. Regrettably, our current lack of knowledge about the diversity and abundance of pathogens in natural systems has made it difficult to establish the relative importance of disease as a significant driver of species extinction, and the context when this is most likely to occur. Here, we review the role of infectious diseases in biological conservation. We summarize existing knowledge of disease-induced extinction at global and local scales and review the ecological and evolutionary forces that may facilitate disease-mediated extinction risk. We suggest that while disease alone may currently threaten few species, pathogens may be a significant threat to already-endangered species, especially when disease interacts with other drivers. We identify control strategies that may help reduce the negative effects of disease on wildlife and discuss the most critical challenges and future directions for the study of infectious diseases in the conservation sciences.

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... The unfilled and filled circles denote the livestock and red panda, respectively. Data from RNP and LNP are pooled Disease transmission associated with 'spill-over ' and 'spill-back' between domestic animals and wildlife can have substantial consequences in human health (Rupprecht et al., 1995), wildlife conservation (Smith et al., 2009) and maintenance of biodiversity (Daszak et al., 2000). Notable examples of cross-transmission of diseases between domestic animals and wildlife include rabies virus and canine distemper virus, which have contributed to the decline of many carnivores including African wild dog (Lycaon pictus; e.g., Ginsberg et al., 1995;Roelke-Parker et al., 1996), Ethiopian wolf (C. ...
... can help maintain genetic variation in immunity among host species (Smith et al., 2009), a high parasite load or a cross-over to non-natural host species can have undesirable consequences. ...
Article
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Abstract Background: Disease transmission among humans, domestic animals and wildlife can have profound consequences in human health, wildlife conservation and maintenance of biodiversity. The issue of disease transmission can be particularly important for threatened wildlife species, yet such information remains scarce due to logistic con- straints and government regulation on animal handlings. The red panda (Ailurus fulgens) is one of the globally threatened species challenged with habitat fragmentation and human disturbance. In Nepal, livestock grazing is recognised as one of the major threats to the red panda. Aim: We aimed to provide the first empirical data on gastro-intestinal parasites for sympatric livestock and red panda from two geographically isolated regions in Nepal. Methods: In this study, we systematically sampled, and examined the faecal of livestock and red panda in two separate protected areas to provide the first empirical data on their gastro-intestinal parasite, including the prevalence, parasite richness and load. Results: We documented 11 parasite taxa (7 nematodes, 2 cestodes, 1 trematode and 1 coccidian), of which 8 are shared by both livestock and red panda. Furthermore, par- asite prevalence, parasite load and parasite richness were generally higher in the live- stock than the red panda. Conclusion: The data provided from this systematic survey on parasites of sympatric livestock and red panda in wild raises the concern about the potential role of live- stock mediating disease dynamics in the red panda. Our study suggests that cross- transmission of parasites between livestock and red panda are likely, and the livestock may be a competent agent bringing disease to both red panda and human. Therefore, managing human-livestock-wildlife contact to reduce disease risk to all groups should be a key component in conservation planning of protected areas.
... In recent years, evidence on disease impact on wildlife populations has accumulated. Due to its multifactorial nature, a minimal understanding of the epizootiology of most diseases is often reached sometime after their effects emerge, with alarming consequences for local populations that hinder efforts to prevent global declines and extinctions (Smith et al. 2009;Fisher et al. 2012;Heard et al. 2013). Epidemiological frameworks that take into account high-risk environmental contexts prone to pathogen emergence and transition to disease have been developed to anticipate and avoid major outbreaks (Grenfell et al. 2004;Beldomenico and Begon 2010;Tompkins et al. 2011). ...
... Under strong and spatially widespread anthropogenic pressure, multiple physiological processes can be impaired in a substantial fraction of populations, with important health consequences (Acevedo-Whitehouse and Duffus 2009; Smith et al. 2009;Gottdenker et al. 2014). Depending on the major risks associated with environmental degradation, poor body condition, and susceptibility to infectious and noninfectious diseases can arise through nutritional deficiencies, immunosuppression, metabolic disorders, and dysbiosis of the microbiota, which are generally interrelated (Elsasser et al. 2000;Wobeser 2013;Becker et al. 2015). ...
Article
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Anthropogenic stressors can favor the occurrence of non-infectious disease that can be worsened by the impact of opportunistic pathogens, making the epizootiology of environmental diseases difficult to unravel. The incidence and impact of oral lesions in nestlings of a facultative scavenger species, the black kite Milvus migrans, were examined over seven breeding seasons in the highly degraded environment close to Madrid, Spain. We found an overall prevalence of 31% of nestlings with oral lesions, with no clear spatial pattern in nests with affected and unaffected individuals. The occurrence and number of oral lesions was negatively associated with nestling body condition and brood size. Broods where all siblings had oral lesions were smaller than those where some or all siblings were apparently healthy, suggesting that oral disease could be causing nestling mortality and, consequently, brood size reduction. In turn, nestling body condition was negatively affected by lesion occurrence, brood size and laying date. Although these relationship were bidirectional, piecewise structural equation modeling analyses showed a greater negative effect of body condition on lesion occurrence than vice versa, indicating that nestlings in poorer body condition were more likely to develop oral lesions (which could contribute to aggravate their state of deterioration) than those in better condition. Nestlings from small broods were also more likely to have oral disease (directly or indirectly through their lower body condition) than nestlings from large broods. Nestlings that hatched last in the broods showed greater development stress than those that hatched first. Anthropogenic stressors could trigger poor body condition, and contribute to microbiota dysbiosis-related diseases. Although further research is needed to determine the consequences for the long-term fitness of individuals, actions should be taken to mitigate adverse conditions that may favor the appearance of environmental diseases associated with peri-urban areas, given their rapid expansion over natural areas.
... There is a growing concern about the emergence of infectious diseases which are currently considered as one of the major threats to the conservation of species. Emerging infectious diseases can cause large population declines and even lead them to extinction (Smith et al. 2009); therefore, the study of the adaptive capacity of species to emerging infectious diseases becomes relevant. The major histocompatibility complex (MHC) genes encode for key elements of the immune and autoimmune systems and are related to adaptation to infectious diseases, thus it is widely used in population genetics for the assessment of population viability. ...
... Another major threat to the conservation of L. provocax is the transmission of infectious diseases, which are often found to be associated with declines in carnivore populations (Wengert et al. 2012). Confined and free-ranging domestic dogs (Canis l. familiaris), which are present in the current habitat of L. provocax, are well-known pathogen reservoirs, thus the increased land use for anthropogenic purposes enhance the contact with wildlife and therefore increase the transmission of emerging infectious diseases (Smith et al. 2009). In fact, Sepúlveda et al. (2014) found samples of American Mink (Neovison vison), an alien species established in southern Chile, with high seroprevalence of Canine Distemper Virus (CDV) and proposed that this species might serve as a bridge host for pathogens between domestic species (e.g., domestic dog, C. l. familiaris; domestic cat, Felis s. catus) and L. provocax. ...
Article
The major histocompatibility complex (MHC) is a highly polymorphic gene group that mediates the vertebrate immune response through antigen recognition and presentation. The ability to face an emerging infectious disease is greatly attributable to the genetic diversity of the MHC genes due to its main role in the adaptive immune response of vertebrates. The Huillín (Lontra provocax) is an endangered otter from southern Chile whose populations have been threatened due to illegal fur trade and displaced as a result of land use change in southern Chile, facilitating contact with domestic animals and allowing the transmission of infectious diseases. In this study, MHC loci from wild populations of L. provocax were assessed for the first time. Variation and signature of selection were estimated for MHC class I exons 2 and 3, and MHC class II DRB exon 2. Low genetic diversity was found for MHC whereas signatures of historical positive selection are suggested but inconclusive. The recent population bottleneck that occurred in L. provocax due to anthropogenic pressures might have unchained a strong genetic drift that overcomes the effects of positive selection in the MHC loci, diminishing genetic diversity and erasing signatures of selection. These results suggest that L. provocax has a low adaptive capacity and, therefore a great susceptibility to the spread of diseases from domestic and invasive animals towards the endangered L. provocax. This should be considered as a warning about the vulnerability of the species to face emerging infectious diseases.
... Infectious diseases pose a significant threat to global biodiversity and require extensive research and resources to manage [1][2][3]. Documenting selection pressure imposed by infectious diseases in natural systems remains challenging due to complex disease-host relationships and the myriad factors influencing host fitness. Previous research has demonstrated a relationship between wildlife disease phenotypes and diversity in immune-related genes such as the major histocompatibility complex (MHC) [4][5][6], with less focus on variation in other genes [7]. ...
... Infectious diseases pose a threat to global biodiversity [1,2], and understanding how free-ranging wildlife populations respond to infectious diseases is essential for effective management and conservation [54]. Documentation of disease-mediated selection in free-ranging animal populations remains limited despite the significant selection pressure that infectious diseases can impose. ...
Article
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Infectious diseases play an important role in wildlife population dynamics by altering individual fitness, but detecting disease-driven natural selection in free-ranging populations is difficult due to complex disease-host relationships. Chronic wasting disease (CWD) is a fatal infectious prion disease in cervids for which mutations in a single gene have been mechanistically linked to disease outcomes, providing a rare opportunity to study disease-driven selection in wildlife. In Wyoming, USA, CWD has gradually spread across mule deer (Odocoileus hemionus) populations, producing natural variation in disease history to evaluate selection pressure. We used spatial variation and a novel temporal comparison to investigate the relationship between CWD and a mutation at codon 225 of the mule deer prion protein gene that slows disease progression. We found that individuals with the 'slow' 225F allele were less likely to test positive for CWD, and the 225F allele was more common in herds exposed to CWD longer. We also found that in the past 2 decades, the 225F allele frequency increased more in herds with higher CWD prevalence. This study expanded on previous research by analysing spatio-temporal patterns of individual and herd-based disease data to present multiple lines of evidence for disease-driven selection in free-ranging wildlife.
... Although wildlife is frequently thought of as a conduit for transmitting infections to humans and domestic animals, the reverse is also true and 80% of domesticated animal pathogens can infect wildlife (Cleaveland et al. 2001). This threatens the environment when diseases transmitted from domestic animals cause the death of wild animals (Pastoret et al. 1988, Kock et al. 1999, Smith et al. 2009). For example, the expansion of livestock production promoted the spread of the rinderpest morbillivirus, which was first introduced by humans in Ethiopia, and caused significant damages to wild animal populations. ...
... Nowadays, concerns about infectious pathogens are increasing with cumulative effects of land development (e.g. habitat loss, environmental pollution), globalization and climate change (Smith et al. 2009). For example, the increasing encroachment of human activities on wildlife habitats and the international trade of wildlife has led to an increase in interactions between humans, domestic animals and wildlife, which creates more possibilities for transmission of pathogens. ...
Thesis
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My thesis focused on understanding the social ecology of African buffalo in several southern African populations to better understand the risk of pathogen transmission within this species. Using GPS and genetic data from buffalo, the objectives of my thesis were to (1) quantify the dynamics of interactions within and between groups of buffalo and examine the influence of seasonality and inter-population variance on these dynamics; (2) investigate whether dispersal was sex-biased at different two organizational levels, i.e. between groups and between populations, to assess the influence of animal sex in pathogen spread between populations; and (3) examine the impact of intragroup dynamics on the spread of a directly transmitted pathogen as a model to link host social organization and pathogen transmission.
... Disease has not traditionally been considered as a significant driver of species extinction but it can also cause, directly or indirectly, decline in wild populations (Smith et. al. 2008). Wild animals serves as reservoir for transmission of infectious diseases to humans as well as domestic animals (Kruse et. al. 2004). Approximately sixty percent of the human pathogens (1415) are zoonotic in nature and seventy percent of these zoonotic pathogens were originated from wildlife (Taylor et. al. 2001). Early detection of dis ...
... rom wildlife (Taylor et. al. 2001). Early detection of diseases in wild animals is very important for management/prevention of disease outbreaks in wild animals as well as emerging infectious diseases in human. The major limitations to diagnose wild life diseases are lack of information and availability of biological material from affected animals (Smith et. al. 2008). Thus collection and preservation of biological samples from free living and captive wild animals are very important to know the epidemiology of the diseases. ...
Book
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Collection, handling and preservation of samples are also very important and critical. Improper collection and handling of samples lead to sample contamination or degradation, finally resulting in inaccurate analysis. Genetic material is fragile and can suffer degradation if stored in inappropriate conditions. A detailed description of the different steps necessary for sample collection and preservation is explained in this book.
... It is considered an emerging panzootic diseasecausing epizootics that can significantly affect wild mammals (Astorga et al., 2018;Escobar et al., 2021). Mange is responsible for alopecia, epidermal crust, and pruritic dermatitis, even leading to death due to secondary infections, starvation, and hypothermia (Bornstein et al., 2001;Smith et al., 2009). Mange has especially impacted populations already threatened by other factors, even triggering local extinctions (Escobar et al., 2021;Pence & Ueckerman, 2002). ...
... These two groups include many domestic animals that can act as reservoirs or vectors of pathogens shared with the wild fauna, particularly with their wild relatives (Astorga et al., 2018;Pedersen et al., 2007;Smith et al., 2009). Sarcoptic mange has been widely documented in canids (grey wolf Canis lupus, coyote Canis latrans, red fox Vulpes vulpes), ungulates (white-tailed deer Odocoileus virginianus, wild boar Sus scrofa), black bear (Ursus americanus) and raccoon (Procyon genus) from North America (Niedringhaus et al., 2019). ...
Article
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Sarcoptic mange is considered an emerging disease causing countless epizootics and significantly affecting wild mammals worldwide. The vicuña (Vicugna vicugna) is a medium‐sized South American wild camelid inhabiting Andean ecosystems, where several populations are live‐sheared by Andean peasant communities as a way of providing an economic income to the people while promoting vicuña conservation. Institutions and scientists have shown concern for the impact and extent of sarcoptic mange in several vicuña populations across their range, as well as the lack of consistent knowledge about this disease in the species. Here we perform a review about sarcoptic mange distribution throughout the vicuña's native range, evidence of effects of age and sex, the modes of transmission and the veterinary treatments employed. The review retrieved few scientific papers, but found several reports and academic studies mostly considered as ‘grey literature’. Mange was recorded across the entire native vicuña range (Argentina, Bolivia, Chile and Peru). Mange prevalence varied across vicuña studies (up to 60% prevalence in some populations) and severely affected a number of populations, being an important source of mortality. Mange was reported as more frequent in adults than in offspring. The modes of mange transmission remain unclear, although direct transmission between infected and healthy animals seems to be the most likely, including the transmission between domestic camelids and vicuñas. Regarding the treatments employed, ivermectin was the most frequently used. We further identified several gaps in knowledge and point to future research lines, which seek to promote both species conservation and the maintenance of live‐shearing vicuñas under sustainable approaches in low‐income Andean peasant communities. This article is protected by copyright. All rights reserved
... The role of degradation of natural ecosystems on wildlife heath and diseases are growingly highlighted worldwide. Concerns around these impacts have been especially reported for emerging diseases threatening wildlife just when their effects are patent after dramatic population declines (Aguirre and Tabor, 2008;Smith et al., 2009;Fisher et al., 2012;Tompkins et al., 2015), generally because the lack of widespread surveillance systems (Kelly et al., 2021). Research on disease-causing processes in wildlife increasingly underscores the impact of human disturbances on ecosystems (Acevedo-Whitehouse and Duffus, 2009;Brearley et al., 2013;Hassell et al., 2017). ...
... Multiple interrelated physiological processes can be affected by contaminants, biotoxins and pathogens acquired through multiple pathways, resulting in nutritional deficiencies, immunosuppression, metabolic disorders, and microbiota alteration (Strandin et al., 2018;Encarnação et al., 2019;Murray et al., 2020;Dujon et al., 2021). Depending on the extent, frequency and intensity of these impacts, populations may be directly and indirectly harmed by environmental and infectious diseases in varying proportion and intensity (Acevedo-Whitehouse and Duffus, 2009;Smith et al., 2009;Gottdenker et al., 2014). The disease triangle framework has often been applied to understand how the interactions between environmental factors, host susceptibility, pathogen virulence and anthropogenic factors such as contaminants lead to different disease stages or impacts (Scholthof, 2007). ...
Article
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Degradation of natural ecosystems increases the risk of infections in wildlife due to microbiota dysbiosis. However, little is known about its influence on the development of fungal communities in predators and facultative avian scavengers. We evaluated the incidence of oral disease in wild nestling black kites (Milvus migrans) under contrasting environmental degradation conditions, and explored their oral fungal patterns using molecular methods and multivariate analysis. Oral lesions were found in 36.8% of the 38 nestlings examined in an anthropogenically altered habitat (southeastern Madrid, Spain), but in none of the 105 nestlings examined in a well-conserved natural area (Doñana National Park, Spain). In a subsample of 48 black kites, the composition of the oral fungal community differed among symptomatic nestlings from Madrid (SM) and asymptomatic nestlings from Madrid (AM) and Doñana (AD). Opportunistic fungal pathogens (e.g., Fusarium incarnatum-equiseti species complex, Mucor spp., Rhizopus oryzae) were more prevalent in SM and AM than in AD. Hierarchical clustering and principal component analyses revealed that fungal patterns were distinct between both study areas, and that anthropogenic and natural environmental factors had a greater impact on them than oral disease. Fungal signatures associated with anthropogenic and natural stresses harbored some taxa that could be used to flag oral infection (F. incarnatum-equiseti species complex and Alternaria), indicate environmental degradation (Alternaria) or provide protective benefits in degraded environments (Trichoderma, Epicoccum nigrum and Sordaria). Co-occurrence associations between potentially beneficial and pathogenic fungi were typical of AM and AD, hinting at a possible role in host health. This study shows that early-life exposure to highly degraded environments induces a shift towards a higher prevalence of pathogenic species in the oral cavity of black kites, favoring oral disease. Furthermore, our findings suggest potential ecological applications of the monitoring of oral mycobiome as a bioindication of oral disease and environmental degradation.
... Wildlife populations worldwide are threatened with unprecedented declines (Knick et al., 2010;May, 2010;Smith et al., 2009). For example, shorebird populations are decreasing (Butchart et al., 2010), half of the world's ungulate and carnivore species are at higher risk of extinction than in the 1970s (Bowyer et al., 2019;Di Marco et al., 2014), and 43% of amphibian species have experienced recent declines with 33% being at risk of extinction (Stuart et al., 2004). ...
Article
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Abstract Many global wildlife populations are experiencing unprecedented declines. Estimates of population abundance are needed to effectively manage common species and to conserve vulnerable species. Camera traps have advanced as wildlife monitoring tools for ungulates and can provide improved methods of estimating population abundance. Little is known, however, about how camera traps set for ungulates compare with traditional methods (e.g., ground and aerial surveys) used simultaneously. From 2012 to 2014, we captured and radio collared 34 female and 32 male bighorn sheep (Ovis canadensis) in a closed population in Utah, USA. Each collar had a unique letter and number combination. We then estimated number of young, females and yearlings, males and population abundance using multiple methods simultaneously: helicopter surveys, resight surveys performed from the ground, camera trap surveys using marked but not individually identifiable individuals and camera trap surveys using marked and individually identifiable animals. All methods estimated similar abundance. Across years, ages and sexes, however, camera trap surveys produced the most consistent and precise estimates of abundance for adult females and yearlings, lambs and the population. That method was less intrusive and safer than helicopter surveys. Our results indicate that camera trap surveys using photographs of marked animals in which the majority of the population visits a specific resource can produce precise estimates of abundance that are safer, as well as less intrusive and expensive than traditional methods. Using camera traps also creates a permanent record of photographs that can be archived and reanalyzed to answer future ecological and population questions. Finally, this method of estimating abundance can be used in other areas with ungulates that congregate around resources (e.g., watering sites or mineral licks).
... We recommend routine monitoring of wildlife for infectious diseases (Watsa, 2020) in tandem with the Convention on International Trade in Endangered Species and Wild Fauna and Flora (CITES) (D'Cruze and Macdonald, 2016) to better inform bushmeat trade regulations. This may not only reduce spillover events to humans (Halliday et al., 2012;Hattendorf et al., 2017), but also provide information on overall ecosystem health (Leroy et al., 2004;Smith et al., 2009;Thompson et al., 2010). Illegal bushmeat hunting is an existential threat for some species, particularly primates (Benítez-López et al., 2017;Ripple et al., 2016;Rogan et al., 2017). ...
Article
The novel coronavirus (SARS-CoV-2) is the third coronavirus this century to threaten human health, killing more than two million people globally. Like previous coronaviruses, SARS-CoV-2 is suspected to have wildlife origins and was possibly transmitted to humans via wet markets selling bushmeat (aka harvested wild meat). Thus, an interdisciplinary framework is vital to address the nexus between bushmeat, wet markets, and disease. We reviewed the contemporary scientific literature to: (1) assess disease surveillance efforts within the bushmeat trade and wet markets globally by compiling zoonotic health risks based on primarily serological examinations; and (2) gauge perceptions of health risks associated with bushmeat and wet markets. Of the 58 species of bushmeat investigated across 15 countries in the 52 articles that we analyzed,one or more pathogens (totaling 60 genera of pathogens) were reported in 48 species, while no zoonotic pathogens were reported in 10 species based on serology. Burden of disease data was nearly absent from the articles resulting from our Scopus search, and therefore was not included in our analyses. We also found that perceived health risks associated with bushmeat was low, though we could not perform statistical analyses due to the lack of quantitative perception-based studies. After screening the literature, our results showed that the global distribution of reported bushmeat studies were biased towards Africa, revealing data deficiencies across Asia and South America despite the prevalence of the bushmeat trade across the Global South. Studies targeting implications of the bushmeat trade on human health can help address these data deficiencies across Asia and South America. We further illustrate the need to address the nexus between bushmeat, wet markets, and disease to help prevent future outbreaks of zoonotic diseases under the previously proposed "One Health Framework", which integrates human, animal, and environmental health. By tackling these three pillars, we discuss the current policy gaps and recommend suitable measures to prevent future disease outbreaks.
... Wild carnivores are threatened by habitat fragmentation, climate change, hunting, and loss of prey [1,2]. Infectious diseases are considered a threat, and the growth of human populations and consequent increase in domestic animals around protected areas ...
Article
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In this study, internal organs (tongue, intestine, and spleen) of 23 free-ranging Italian wolves (Canis lupus italicus) found dead between 2017 and 2019 were tested for Carnivore protoparvovirus 1, Canine adenovirus (CAdV), and Canine circovirus (CanineCV) using real-time PCR assays. Genetic characterisation of the identified viruses was carried out by amplification, sequencing, and analysis of the complete viral genome or informative viral genes. All the wolves tested positive for at least one of the DNA viruses screened, and 11/23 were coinfected. Carnivore protoparvoviruses were the most frequently detected viruses (21/23), followed by CanineCV (11/23) and CAdV (4/23). From the analysis of the partial VP2 gene of 13 carnivore protoparvoviruses, 12 were canine parvovirus type 2b, closely related to the strains detected in dogs and wild carnivores from Italy, and one was a feline panleukopenia-like virus. Of the four CAdV identified, two were CAdV-1 and two were CAdV-2. The complete genome of seven CanineCVs was sequenced and related to the CanineCV identified in dogs, wolves, and foxes worldwide. Close correlations emerged between the viruses identified in wolves and those circulating in domestic dogs. Further studies are needed to investigate if these pathogens may be potentially cross-transmitted between the two species.
... The population of these species is declining due to different reasons including habitat loss and degradation, poaching and illegal trades, diseases, human-wildlife con icts, etc. Infectious diseases and parasites are the major concern in the conservation of these species as they can lead to mortality, dramatic population declines, and even contribute to local extinction events (Smith, Acevedo-Whitehouse, & Pedersen, 2009). This study attempts to investigate the prevalence of gastrointestinal parasites in wild deer having regular interaction with the livestock in buffer zones of Chitwan National park. ...
Preprint
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Deer are the hoofed ruminants of the order Artiodactyla and suborder Ruminantia in which infectious disease and parasites are of major concern in their conservation. This speci c research helps us to determine the transmission of gastrointestinal parasites between deer and livestock in the buffer zone. Fecal examination for the parasitic load was carried out using Floatation and Sedimentation techniques. 96.49% of the total fecal samples tested for parasitic eggs were found to be positive for the prevalence of gastro-intestinal parasite whereas parasitic prevalence in livestock of Buffer Zone i.e. Sauraha and Bachhauli area was calculated to be 87.30% based on the examination conducted within that same period and same area by the veterinary hospital. Pramphistomum was the most prevalent one in both deer (72.72%) and livestock (52.63%). The nding of this research revealed the higher chances of the exchange of parasites between the deer and livestock. A more advanced study must be done in this sector and concerned authorities should develop and implement effective plans to prevent cross-transmission of parasites between deer and livestock and other wildlife.
... Because of their feeding behavior, which involves hunting and carcass scavenging, these animals are constantly exposed to a high number of infectious agents and play a crucial role in disease spread, especially considering that many carnivore parasites are multi-host, i.e., capable of infecting multiple species [37,38]. Identifying microorganisms of carnivores and studying their host distribution and transmission dynamics has, therefore, important implications for animal health and conservation programs [39], especially since cross-species transmission does happen frequently and sometimes with catastrophic consequences [37,40]. In this manuscript, we fully characterized and investigated the epidemiology and host distribution of Newlavirus, a novel parvovirus we discovered in foxes. ...
Article
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The genus Protoparvovirus (family Parvoviridae) includes several viruses of carnivores. We describe a novel fox protoparvovirus, which we named Newlavirus as it was discovered in samples from Newfoundland and Labrador, Canada. Analysis of the full non-structural protein (NS1) sequence indicates that this virus is a previously uncharacterized species. Newlavirus showed high prevalence in foxes from both the mainland (Labrador, 54/137, 39.4%) and the island of Newfoundland (22/50, 44%) but was not detected in samples from other carnivores, including coyotes (n = 92), lynx (n = 58), martens (n = 146), mink (n = 47), ermines (n = 17), dogs (n = 48), and ringed (n = 4), harp (n = 6), bearded (n = 6), and harbor (n = 2) seals. Newlavirus was found at similar rates in stool and spleen (24/80, 30% vs. 59/152, 38.8%, p = 0.2) but at lower rates in lymph nodes (2/37, 5.4%, p < 0.01). Sequencing a fragment of approximately 750 nt of the capsid protein gene from 53 samples showed a high frequency of co-infection by more than one strain (33.9%), high genetic diversity with 13 genotypes with low sequence identities (70.5–87.8%), and no geographic segregation of strains. Given the high prevalence, high diversity, and the lack of identification in other species, foxes are likely the natural reservoir of Newlavirus, and further studies should investigate its distribution.
... Fragmentación y pérdida de hábitat Las actividades antrópicas que más han afectado la salud de la fauna silvestre son la pérdida, fragmentación y perturbación del hábitat, así como la contaminación (Primack, 2002;Pullin, 2002). Por ejemplo, la pérdida y fragmentación del hábitat puede disminuir la disponibilidad de alimento y ocasionar un deterioro del estado nutricional; además de que restringen el movimiento de los animales, lo que limita el flujo genético e incrementa las oportunidades de contacto entre los humanos, animales domésticos y fauna silvestre, con el consiguiente aumento en la tasa de transmisión de enfermedades (Lanfranchi et al., 2003;Smith et al., 2009). ...
Book
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This book summarizes the ecology and conservation of Baird's tapir in Mexico. It is edited in Spanish
... However, models show that these populations are two to five times more likely to cross the risk threshold of drastic decline in the next 60 years, if mild human-induced perturbations continue, alongside the present natural disturbance [85]. The combination of disease with other environmental or anthropogenic stressors can impose significant conservation threats [88][89][90]. This is illustrated by Obanda et al. [91], which suggest that infections with the liver fluke P. robusta have a synergetic effect with drought-related starvation in massmortality of African elephants in Kenya. ...
Article
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Background: Humans impose a significant pressure on large herbivore populations, such as hippopotami, through hunting, poaching and habitat destruction. Anthropogenic pressures can also occur indirectly, such as artificial lake creation and the subsequent introduction of invasive species that alter the ecosystem. These events can lead to drastic changes in parasite diversity and transmission, but generally receive little scientific attention. Results: In order to document and identify trematode parasites of the common hippopotamus (Hippopotamus amphibius) in artificial water systems of Zimbabwe, we applied an integrative taxonomic approach, combining molecular diagnostics and morphometrics on archived and new samples. In doing so, we provide DNA reference sequences of the hippopotamus liver fluke Fasciola nyanzae, enabling us to construct the first complete Fasciola phylogeny. We describe parasite spillback of F. nyanzae by the invasive freshwater snail Pseudosuccinea columella, as a consequence of a cascade of biological invasions in Lake Kariba, one of the biggest artificial lakes in the world. Additionally, we report an unknown stomach fluke of the hippopotamus transmitted by the non-endemic snail Radix aff. plicatula, an Asian snail species that has not been found in Africa before, and the stomach fluke Carmyerius cruciformis transmitted by the native snail Bulinus truncatus. Finally, Biomphalaria pfeifferi and two Bulinus species were found as new snail hosts for the poorly documented hippopotamus blood fluke Schistosoma edwardiense. Conclusions: Our findings indicate that artificial lakes are breeding grounds for endemic and non-endemic snails that transmit trematode parasites of the common hippopotamus. This has important implications, as existing research links trematode parasite infections combined with other stressors to declining wild herbivore populations. Therefore, we argue that monitoring the anthropogenic impact on parasite transmission should become an integral part of wildlife conservation efforts.
... A closely related factor, and often associated with BCI, affecting disease prevalence is season. For example, harsh weather conditions and temperature fluctuations will often result in poor nutrition (Smith et al. 2009) and low investment in reproduction, and weaken immune system (Dowell 2001;Pedersen 2009). These effects may cause undesirable consequences for wild felid species, so it is particularly important to protect native carnivores from these unpredictable outcomes (Ferreira and Funston 2010). ...
Article
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One of the key factors influencing the population dynamics of threatened species such as felids is disease, but long-term studies of the factors influencing seroprevalence of wild felids are extremely rare, hindering conservation efforts. We set out to determine seroprevalence of six viral diseases (feline panleukopenia virus, feline leukemia virus, feline coronavirus, feline calicivirus, feline herpes virus, and feline immunodeficiency virus) among a population of serval (Leptailurus serval) with an extremely high density in South Africa. We captured 55 individuals over four years and screened blood samples for antibodies to each virus. We found that seroprevalence were high (ranging from 30.0% positive for a single virus to 1.8% positive for up to five viruses) and that seroprevalence was influenced by season and sex, but not body condition. We suggest further monitoring of this population and recommend that long-term studies are conducted for serval and other felids to determine whether these trends are representative on a broader scale.
... Parrots and their associated diseases are moved at a global scale through the pet trade (Smith et al. 2009;Symes et al., chap. 17 this vol.). ...
... On rangelands, the primary resource for domestic and wild ungulates is pasture (Berger et al., 2013). Shared use of rangelands can lead to interspecific disease transmission, which can impact agricultural livelihoods (Reid et al., 2008) and wildlife conservation (Smith et al., 2009). ...
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Shared use of rangelands by livestock and wildlife can lead to disease transmission. To align agricultural livelihoods with wildlife conservation, a multi‐pronged and interdisciplinary approach for disease management is needed, particularly in data‐limited situations with migratory hosts. Migratory wildlife and livestock can range over vast areas, and opportunities for disease control interventions are limited. Predictive frameworks are needed which can allow for identification of potential sites and timings of interventions. We developed an iterative three‐step framework to assess cross‐species disease transmission risk between migrating wildlife and livestock in data‐limited circumstances and across social‐ecological scales. The framework first assesses risk of transmission for potentially important diseases for hosts in a multi‐use landscape. Following this, it uses an epidemiological risk function to represent transmission‐relevant contact patterns, using density and distribution of the host to map locations and periods of disease risk. Finally, it takes fine‐scale data on livestock management and observed wildlife‐livestock interactions to provide locally‐relevant insights on disease risk. We applied the framework to characterize disease transmission between livestock and saiga antelopes (Saiga tatarica) in Central Kazakhstan. At step 1, we identified peste‐des‐petits‐ruminants as posing a high risk of transmission from livestock to saigas, foot‐and‐mouth disease as low risk, lumpy skin disease as unknown and pasteurellosis as uncertain risk. At step 2 we identified regions of high disease transmission risk at different times of year, indicating where disease management should be focussed. At step 3, we synthesized field surveys, government data and literature review to assess the role of livestock in the 2015 saiga mass mortality event from pasteurellosis, concluding that it was minimal. Synthesis and Applications. Our iterative framework has wide applicability in assessing and predicting disease spill‐over at management‐relevant temporal and spatial scales in areas where livestock share space with migratory species. Our case study demonstrated the value of combining ecological and social information to inform management of targeted interventions to reduce disease risk, which can be used to plan disease surveillance and vaccination programmes.
... During the last few years, the constant loss of habitats has approached domestic and wild animals, resulting in the emergence of several infectious diseases [11] by the spreading of pathogens among species [3,4,9]. A study performed in the Brazilian Pantanal with 10 gray brockets suggested that the helminth fauna of these animals may have been derived from domestic cattle introduced in that area [3]. ...
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Background: The gray brocket deer (Mazama gouazoubira) is a specie that shows great adaptability in different habitats and it is the most abundant deer specie in South America. The present work describes for the first time a case of abortion followed by death associated with colloid goiter, massive hemonchosis and necrotizing rumenitis in a captive female gray brocket deer. Case: A 4-year-old female gray brocket deer (M. gouazoubira) raised in captivity had a history of abortion during the last third of gestation. The animal was kept in an enclosure together with 3 other gray brockets deers, being 1 male of the same age and 2 juvenile brocket deer of approximately 1 and 2 years old. The animals were fed with concentrated used as cattle feed and dewormed annually with 1% Ivermectin. The animals' enclosure had vegetation cover formed by grasses and soil. The animals appeared healthy with no behavioral changes. The day after the stillbirth, the mother was found dead in the enclosure and sent to the animal pathology sector of the University of Vila Velha (UVV), Brazil. Necropsy revealed that thyroid lobules were highly increased in volume and histopathological findings were compatible with colloid goiter. A large number of nematodes were found in the abomasal content, totalizing 11,626 helminths, which were morphologically characterized as Haemonchus contortus. Grossly, the serous and ruminal mucosa exhibited an extensively reddish focal area with irregular contour, surface ulceration and a firm consistency. Microscopically, a severe necrotizing rumenitis was diagnosed. The liver showed pale multifocal areas on the subcapsular surface, friable to the touch which deepened when cut. Histopathological analysis revealed an accentuated multifocal panlobular coagulative necrosis, characterizing an acute liver necrosis. Discussion: Iodine is a mineral of great importance for thyroid hormones synthesis and your requirements are higher during pregnancy and lactation. Diets deficient in iodine causes a reduction in the basal activity of the hormones triiodothyronine (T3) and thyroxine (T4) and over-stimulation of the thyroid by thyroid stimulating hormone (TSH), resulting in goiter. In the present case, it is possible that the shortage of iodine in diet caused a goiter and, as a consequence, triggered the abortion. Haemonchus contortus is a pathogenic nematode of small ruminants, leading to decreased productivity and death in some cases as a result of anemia and hypoxia. The contact between domestic and wild animals, resulting in the emergence of infectious diseases and the spread of pathogens among species. In the present case, manual counting accounted for 11,626 H. contortus larvae, characterizing a massive infection and justifying the condition of severe anemia. The high parasitic load shown in this case points out this parasite's importance related to this species in captivity. In general, inflammatory lesions in the rumen are results of excessive intake of fermentable carbohydrates, which leads to a considerable decrease in ruminal pH and leads to a high proliferation of lactic acid bacteria. This lesion has been previously reported in cervids. This case of comorbidities demonstrates that failures in nutritional and health handling, may cause simultaneous multiple diseases leading to death. Preventive measures for helminth parasite control and a proper feeding management with an adequate diet must be provided in order to preserve the species in captivity.
... The catastrophic effects of infectious diseases such as Ebola Virus Disease (EVD) and those caused by human respiratory pathogens in wild ape populations have been well documented over the past two decades 7,[12][13][14][15][16][17][18] . Understanding and limiting the transmission of these infectious diseases within ape populations is therefore of high priority when it comes to both the conservation of these critically endangered species 12,19 and the health of human populations 20,21 . ...
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Minimizing disease transmission between humans and wild apes and controlling outbreaks in ape populations is vital to both ape conservation and human health, but information on the transmission of real infections in wild populations is rare. We analyzed respiratory outbreaks in a subpopulation of wild mountain gorillas ( Gorilla beringei beringei ) between 2004 and 2020. We investigated transmission within groups during 7 outbreaks using social networks based on contact and proximity, and transmission between groups during 15 outbreaks using inter-group encounters, transfers and home range overlap. Patterns of contact and proximity within groups were highly predictable based on gorillas’ age and sex. Disease transmission within groups was rapid with a median estimated basic reproductive number (R0) of 4.18 (min = 1.74, max = 9.42), and transmission was not predicted by the social network. Between groups, encounters and transfers did not appear to have enabled disease transmission and the overlap of groups’ ranges did not predict concurrent outbreaks. Our findings suggest that gorilla social structure, with many strong connections within groups and weak ties between groups, may enable rapid transmission within a group once an infection is present, but limit the transmission of infections between groups.
... In the early days of infection, host density-dependent transmission was the main cause of population increase of G. kobayashii. Density-dependent transmission for directly transmitted pathogens has been supported by theoretical models (Anderson and May, 1979;Earn et al., 2000;McCallum et al., 2001;Smith et al., 2009) and empirical evidence from field surveys (Begon et al., 1998;Ramsey et al., 2002;Stringer and Linklater, 2015). Generally, more contacts between parasites and hosts occur at higher density of hosts (Barlow, 1996). ...
Article
Host density is a key regulatory factor in parasite transmission. The goldfish (Carassius auratus)-Gyrodactylus kobayashii model was used to investigate effects of host density on population growth of gyrodactylids. A donor fish infected by five gravid gyrodactylids was mixed with 11 parasite-free goldfish at five host densities. There was a significant positive correlation between host density and mean abundance of G. kobayashii throughout the 58-day experiment. During early infection (days 15–24), mean abundance in medium high (0.5 fish L−1) and high host density groups (1 and 2 fish L−1) was significantly higher than that in the low host density groups (0.125 and 0.25 fish L−1). At high host density, prevalence increased more rapidly, and the peak prevalence was higher. Fitting of an exponential growth model showed that the population growth rate of the parasite increased with host density. A hypothesis was proposed that higher host density contributed to increased reinfection of detached gyrodactylids. A reinfection experiment was designed to test this hypothesis. Both mean abundance and prevalence at a host density of 1 fish L−1 were significantly higher than those at 0.25 fish L−1 on days 1 and 3, which suggested that more reinfections of G. kobyashii occurred at the higher host density. Density-dependent transmission during the early infection was an important contributor of population growth of G. kobayashii, as well as density-dependent reinfection of the detached gyrodactylids.
... (2) broadly expanding our understanding of pathogen diversity in natural systems (Smith et al., 2009 ...
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Successful conservation efforts for threatened species depend on accurate characterization of their distribution, habitat use, and threats. However, surveillance can be challenging for species with small size, cryptic coloring, or elusive behavior. Environmental DNA (eDNA) monitoring can provide a sensitive and noninvasive alternative to traditional surveillance techniques by detecting trace DNA shed by a target species into their environment. We evaluated the efficacy of eDNA monitoring for the four‐toed salamander (Hemidactylium scutatum), a terrestrial salamander threatened throughout much of its range. Additionally, we integrated eDNA monitoring for ranavirus, a widespread pathogen of ectothermic vertebrates, to efficiently evaluate a potential disease threat to H. scutatum. We designed a novel species‐specific quantitative PCR (qPCR) assay for H. scutatum, multiplexed the assay with a previously developed ranavirus qPCR assay, and validated the multiplexed tests in silico, in vitro, and in situ. We collected aquatic eDNA weekly for 8 weeks from pools with historical reports of H. scutatum (n = 6) and contemporary reports of H. scutatum on associated uplands (n = 4). We identified H. scutatum eDNA at low quantities (< 12 copies/reaction) on multiple sampling days in two pools with historic species presence. Ranavirus eDNA was widespread; nine pools tested positive including the pools where H. scutatum eDNA was detected. Ranavirus eDNA quantities increased, peaked, then decreased (i.e., were not sporadic in time) in several pools but never rose in abundance to levels associated with ranavirosis in other studies. Our results suggest that H. scutatum eDNA is distributed sporadically at low quantities in pools; we recommend that future surveillance efforts prioritize increased frequency and quantity of sample collection per site visit and include repeat surveys of candidate sites. Further work to characterize Ranavirus eDNA movement, temporal trends, relationship to infectious virion, and decay is needed to help advance this tool. Hemidactylium scutatum positive eDNA samples and Ranavirus eDNA concentration in 2017 surveys of New York state amphibian breeding pools. Positive H. scutatum log10 transformed eDNA concentrations are indicated with blue triangles. The mean and standard error of log10 transformed Ranavirus concentration at each sampling event is represented with red circles; open circles indicate a sampling date when all three water samples were Ranavirus negative
... Infectious diseases such as Ebola are considered to be a threat to the survival of African great apes [8], together with other threats such as habitat loss, climate change and poaching [9]. In some cases, the human outbreaks have been linked to contact with infected bushmeat from gorillas or chimpanzees [10] and several surveys have reported dramatic declines in populations of great apes in parallel with human EVD outbreaks with laboratory confirmation of Ebola virus infection in some carcasses [10][11][12]. ...
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Background Numerous Ebola virus outbreaks have occurred in Equatorial Africa over the past decades. Besides human fatalities, gorillas and chimpanzees have also succumbed to the fatal virus. The 2004 outbreak at the Odzala-Kokoua National Park (Republic of Congo) alone caused a severe decline in the resident western lowland gorilla (Gorilla gorilla gorilla) population, with a 95% mortality rate. Here, we explore the immediate genetic impact of the Ebola outbreak in the western lowland gorilla population. Results Associations with survivorship were evaluated by utilizing DNA obtained from fecal samples from 16 gorilla individuals declared missing after the outbreak (non-survivors) and 15 individuals observed before and after the epidemic (survivors). We used a target enrichment approach to capture the sequences of 123 genes previously associated with immunology and Ebola virus resistance and additionally analyzed the gut microbiome which could influence the survival after an infection. Our results indicate no changes in the population genetic diversity before and after the Ebola outbreak, and no significant differences in microbial community composition between survivors and non-survivors. However, and despite the low power for an association analysis, we do detect six nominally significant missense mutations in four genes that might be candidate variants associated with an increased chance of survival. Conclusion This study offers the first insight to the genetics of a wild great ape population before and after an Ebola outbreak using target capture experiments from fecal samples, and presents a list of candidate loci that may have facilitated their survival.
... Further, increased human transportation, land use changes, and global climate change have led to more frequent cases of the introduction or establishment of pathogens into new host species globally [23][24][25] . It is becoming clear that conservation biology must explicitly consider the potential for disease to impact species persistence 26,27 . Infectious disease risks depend directly on shifts in the host population itself. ...
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When a novel disease strikes a naïve host population, there is evidence that the most immediate response can involve host evolution while the pathogen remains relatively unchanged. When hosts also live in metapopulations, there may be critical differences in the dynamics that emerge from the synergy among evolutionary, ecological, and epidemiological factors. Here we used a Susceptible-Infected-Recovery model to explore how spatial and temporal ecological factors may drive the epidemiological and rapid-evolutionary dynamics of host metapopulations. For simplicity, we assumed two host genotypes: wild type, which has a positive intrinsic growth rate in the absence of disease, and robust type, which is less likely to catch the infection given exposure but has a lower intrinsic growth rate in the absence of infection. We found that the robust-type host would be strongly selected for in the presence of disease when transmission differences between the two types is large. The growth rate of the wild type had dual but opposite effects on host composition: a smaller increase in wild-type growth increased wild-type competition and lead to periodical disease outbreaks over the first generations after pathogen introduction, while larger growth increased disease by providing more susceptibles, which increased robust host density but decreased periodical outbreaks. Increased migration had a similar impact as the increased differential susceptibility, both of which led to an increase in robust hosts and a decrease in periodical outbreaks. Our study provided a comprehensive understanding of the combined effects among migration, disease epidemiology, and host demography on host evolution with an unchanging pathogen. The findings have important implications for wildlife conservation and zoonotic disease control.
... Climatic variations, ecosystem fragmentation and changes in livestock management practices are altering rangelands, with implications for the people and wildlife that reside there (Berger et al., 2013;Reid et al., 2014). Shared pasture use can also facilitate disease transmission, with potentially severe implications for wildlife health and conservation (Smith et al., 2009). ...
Article
Contact between wild and domestic ungulates is increasing across rangelands, enabling disease co-transmission. Disease management is difficult given uncertainties in complex system behavior, limited empirical data, and logistical obstacles to interventions. We studied gastrointestinal nematode (GIN) transmission in a rangeland shared by both livestock and the critically-endangered migratory saiga antelope, Saiga tatarica, in order to model infection dynamics under current and plausible future scenarios of increasing livestock numbers, climate change and anti-helminth treatments. Our model was parameterised for trichostrongylid GIN – a cause of mortality and morbidity in ungulates globally - using data on observed faecal nematode egg output and host numbers and distribution. Results showed that seasonal saiga migration leads to asymmetry in parasite transmission, with the majority of GIN acquired by saigas in their autumn and winter range through prior pasture contamination from livestock. Consequently, reducing parasite burdens in livestock early in the season in these areas could disproportionately reduce cross-transmission to saigas. Early-season GIN suppression in livestock in the saiga's spring and summer range was predicted to have weaker effect on parasite transmission to saigas but reduces infections during the calving period, potentially increasing population health and resilience at this critical time. Optimally timed treatments could offset the effects of increasing livestock numbers on GIN infection pressure, while climate warming had only marginal impacts on GIN transmission under all scenarios. Our findings could support better understanding and mitigation of factors affecting saiga health and rural livelihoods. Our approach is transferable to other systems, particularly those with migratory hosts.
... Developing Immune Profiles of Endangered Australian Sea Lion (Neophoca cinerea) Pups Within the Context of Endemic Hookworm (Uncinaria sanguinis) Infection INTRODUCTION Infectious wildlife disease, emerging or endemic, can play a beneficial or neutral role as a component of species ecology or can have detrimental impacts, either directly or as an additive pressure or amplifier of other threats. As such, understanding mechanisms of disease susceptibility can inform conservation management of threatened species (1,2). Measuring variation in innate and adaptive immune parameters offers an additional perspective for health assessment and evaluation of susceptibility to environmental pressures in wildlife populations (3). ...
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As a top predator, the endangered Australian sea lion (Neophoca cinerea) is a sentinel of ecosystem change, where population trends can reflect broader shifts in the marine environment. The population of this endemic pinniped was historically diminished by commercial sealing, and recovery has been slowed by fishery interactions, disease and, potentially, pollutants. Hookworm infects 100% of neonatal pups and has been identified as a contributor to population decline. Here, a multivariable approach using traditional serological and novel molecular tools such as qPCR and ddPCR was used to examine immune phenotypes of developing Australian sea lion pups infected with the endemic hookworm (Uncinaria sanguinis) from two South Australian colonies. Results show changing immunophenotypes throughout the patent period of infection represented by pro-inflammatory cytokines (IL-6), IgG and acute-phase proteins. Although cytokines may prove useful as markers of resistance, in this study, IL-6 is determined to be an early biomarker of inflammation in Australian sea lion pups, excluding the alternative hypothesis. Additionally, immunological differences between animals from high-and low-intensity hookworm seasons, as well as ivermectin-treated animals, indicate hookworm infection modulation of the host immune response, as evidenced by a lower IL-6 mRNA expression in the non-treated groups. This study of the Australian sea lion is an example of an ecoimmunological approach to disease investigation, which can be applied to evaluate the impact of environmental and anthropogenic factors on susceptibility to infectious diseases in free-ranging species
... or from a dead to a live host (Scott and Anderson, 1984). Then, according to the simple transmission function dI/dt = βSI/(S + I ), where β is the transmission coefficient (Getz and Pickering, 1983;Anderson and May, 1992;Lloyd-Smith et al., 2005a, 2005b, S, the number of susceptible hosts, and I as the number of infected hosts (Smith et al., 2009;McCallum et al., 2017), the probability of transmission in the genus Gyrodactylus could be at a rate βSI (frequency-dependent transmission) rather than βSI/N (densitydependent transmission) (Heggberget and Johnsen, 1982;Jensen, 1986, 1992;Johnson et al., 2011;Zhou et al., 2017). Still, because pathogen transmission often occurs through more than one route, each of which may have a different functional relationship with population density (Ryder et al., 2007), it is likely that Gyrodactylus transmission combines frequency-and density-dependent dynamics. ...
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Parasite transmission is the ability of pathogens to move between hosts. As a key component of the interaction between hosts and parasites, it has crucial implications for the fitness of both. Here, we review the transmission dynamics of Gyrodactylus species, which are monogenean ectoparasites of teleost fishes and a prominent model for studies of parasite transmission. Particularly, we focus on the most studied host–parasite system within this genus: guppies, Poecilia reticulata, and G. turnbulli/G. bullatarudis . Through an integrative literature examination, we identify the main variables affecting Gyrodactylus spread between hosts, and the potential factors that enhance their transmission. Previous research indicates that Gyrodactylids spread when their current conditions are unsuitable. Transmission depends on abiotic factors like temperature, and biotic variables such as gyrodactylid biology, host heterogeneity, and their interaction. Variation in the degree of social contact between hosts and sexes might also result in distinct dynamics. Our review highlights a lack of mathematical models that could help predict the dynamics of gyrodactylids, and there is also a bias to study only a few species. Future research may usefully focus on how gyrodactylid reproductive traits and host heterogeneity promote transmission and should incorporate the feedbacks between host behaviour and parasite transmission.
... Especially locally restricted and "superficial" bone lesions might not be detected, biasing our awareness of the impact of especially infectious diseases on past animal populations. In wildlife conservation pathogens are recognised to facilitate extinction risk at least in already threatened species (Smith et al., 2006;Smith et al., 2009;Cunningham et al., 2017), but recent data is still sparse and historical evidence missing. However, in a study of late Pleistocene Mastodon bones, half of the individuals in the sample show lesions indicative of tuberculosis (Rothschild and Laub, 2006), and DNA of the respective pathogen Mycobacterium tuberculosis was detected in a late Pleistocene bison (Rothschild et al., 2001), nourishing the hypothesis of a pandemic disease contributing to faunal extinction at the Pleistocene-Holocene boundary in North America. ...
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The article presents the diagnosis and aetiology of an arthropathological horse (Equus sp.) radius from the Middle Palaeolithic site of Pfeddersheim (Rhine-Hesse, Germany). For the contextualisation of the results the chronological and archaeological frame of the site, the taphonomic history of the faunal assemblage and site formation are summarised. A fracture of the ulna caused a malposition of the humeroradial joint, that developed into a degenerative arthrosis with severe grooving of the articular surface of the radius, extension of the joint by new bone formation and exostosis around the epiphysis. The progression of the disease from the trauma to the final grade of arthrosis and how it affected the horse's life is portrayed. Eventually, the horse fell prey to a large carnivore. Finally, the palaeoecological significance of this very specific palaeopathological finding is discussed.
... Pathogens pose a key threat to mammalian wildlife populations; according to the IUCN red list, 25% of carnivores are threatened and 8% of the 36 species in the family Felidae are threatened by diseases (Smith et al., 2009). Knowing the immune competence of threatened species is particularly important for conservation management because it is a critical aspect of disease resistance and the resilience of a population (Heinrich et al., 2016). ...
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This review summarizes the current knowledge on the major histocompatibility complex (MHC) of the family Felidae. This family comprises an important domestic species, the cat, as well as a variety of free-living felids, including several endangered species. As such, the Felidae have the potential to be an informative model for studying different aspects of the biological functions of MHC genes, such as their role in disease mechanisms and adaptation to different environments, as well as the importance of genetic diversity for conservation issues in free-ranging or captive populations. Despite this potential, the current knowledge on the MHC in the family as a whole is fragmentary and based mostly on studies of the domestic cat and selected species of big cats. The overall structure of the domestic cat MHC is similar to other mammalian MHCs following the general scheme "centromere-MHC class I-MHC class III-MHC class II" with some differences in the gene contents. An unambiguously defined orthologue of the non-classical class I HLA-E gene has not been identified so far and the class II DQ and DP genes are missing or pseudogenized, respectively. A comparison with available genomes of other felids showed a generally high level of structural and sequence conservation of the MHC region. Very little and fragmentary information on in vitro and/or in vivo biological functions of felid MHC genes is available. So far, no association studies have indicated effects of MHC genetic diversity on a particular disease. No information is available on the role of MHC class I molecules in interactions with Natural Killer (NK) cell receptors or on the putative evolutionary interactions (co-evolution) of the underlying genes. A comparison of complex genomic regions encoding NK cell receptors (the Leukocyte Receptor Complex, LRC and the Natural Killer Cell Complex, NKC) in the available felid genomes showed a higher variability in the NKC compared to the LRC and the MHC regions. Studies of the genetic diversity of domestic cat populations and/or specific breeds have focused mainly on DRB genes. Not surprisingly, higher levels of MHC diversity were observed in stray cats compared to pure breeds, as evaluated by DRB sequencing as well as by MHC-linked microsatellite typing. Immunogenetic analysis in wild felids has only been performed on MHC class I and II loci in tigers, Namibian leopards and cheetahs. This information is important as part of current conservation tasks to assess the adaptive potential of endangered wild species at the human-wildlife interface, which will be essential for preserving biodiversity in a functional ecosystem.
... Nevertheless, their dependence on large landscapes for shelter and reproduction, and stable prey populations makes carnivores vulnerable to habitat loss, modification, and fragmentation (Henle et al., 2004;Wilcox and Murphy, 1985). Landscape transformation also favors the spread of new pathogens (Sacristán et al., 2021), which can be potentially harmful, once free-ranging carnivores tend to be immunosuppressed (Daszak et al., 2000;Smith et al., 2009). Thus, carnivores are considered sensitive indicators of anthropogenic impact over the environment (Hunter and Barrett, 2018;Karanth and Chellam, 2009). ...
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Landscape transformation favors the spread of new pathogens that can be shared between domestic and wild animals. Certain adenoviruses (e.g., canine adenovirus 1 and 2, family Adenoviridae) can infect domestic and wild carnivores. In domestic canids, these viruses are associated with hepatic and respiratory diseases (among others). Nevertheless, information regarding adenovirus pathogenicity and molecular features in wild carnivores is still limited. Herein we surveyed adenovirus in free-ranging carnivores from Brazil. Total DNA was extracted from and subsequently tested by a nested panPCR in spleen and/or lung of 52 carnivores, representing species of the following families: Canidae (n = 4), Felidae (n = 3), Mustelidae (n = 2) and Procyonidae (n = 2). The obtained sequences were compared to others available at GenBank. Available tissue samples from the positive cases were evaluated histopathologically. One out of 52 (1.9%, CI 95%, 0.0–5.7%) carnivores was positive; a roadkilled ocelot (Leopardus pardalis). The obtained sequence presented a low deduced amino acid (78.1%) similarity with the closest adenovirus, identified in a pinniped from the United States of America. This fact and its detection in a novel host suggest it may be representative of a novel species and denominated ocelot adenovirus 1. None of the gross and microscopic findings of the positive case were associated with adenovirus. To the authors' knowledge, this is the first report of adenovirus in wild felids of South America and the second worldwide. Further studies are necessary to assess the epidemiology and potential pathogenicity of this agent in wild carnivores.
... Emerging infectious diseases are increasingly recognized as important drivers in the loss of biodiversity (Daszak et al., 2000;Smith et al., 2009). However, there is considerable variation in host response to most diseases. ...
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Research Highlight: Valenzuela‐Sánchez, A., Azat, C., Cunningham, A. A., Delgado, S., Bacigalupe, L. D., Beltrand, J., Serrano, J. M., Sentenac, H., Haddow, N., Toledo, V., Schmidt, B. R., & Cayuela, H. (2022). Interpopulation differences in male reproductive effort drive the population dynamics of a host exposed to an emerging fungal pathogen. Journal of Animal Ecology, 00, 1– 12. https://doi.org/10.1111/1365‐2656.13603. Understanding the nuances of population persistence in the face of a stressor can help predict extinction risk and guide conservation actions. However, the exact mechanisms driving population stability may not always be known. In this paper, Valenzuela‐Sánchez et al. (2022) integrate long‐term mark–recapture data, focal measurements of reproductive effort, a population matrix model and inferences on life‐history variation to reveal differences in demographic response to disease in a susceptible frog species (Rhinoderma darwinii). Valenzuela‐Sánchez et al. found that demographic compensation via recruitment explained the positive population growth rate in their high disease prevalence population whereas the low disease prevalence population did not compensate and thus had decreasing population growth. Compensatory recruitment was likely due to the high probability of males brooding, and the high number of brooded larvae in the high prevalence population compared to low prevalence and disease‐free populations. Valenzuela‐Sánchez et al. also document faster generation times in the high prevalence population, which may indicate a faster life history that may be contributing to the population's ability to compensate for reduced survival. Lastly, the authors find a positive relationship between disease prevalence and the proportion of juveniles in a given population that suggest that there may be a threshold for disease prevalence that triggers increased reproductive effort. Altogether, their study provides novel support for increased reproductive effort as the pathway for compensatory recruitment leading to increasing population growth despite strong negative effects of disease on adult survival. Their results also caution the overgeneralization of the effects of stressors (e.g. disease) on population dynamics, where context‐dependent responses may differ among host populations of a given species. The authors highlight that demographic compensation for deadly diseases may depend on the context of life history, and that high prevalence may not doom natural populations.
... Bagchi et al., 2004). Pasture sharing can also lead to disease transmission, which can impact livestock-based economies and wild ungulate health (Smith et al., 2009). This is particularly relevant for wild ungulates as pathogen assemblages are associated with host phylogeny (e.g. ...
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Rangelands are multi‐use landscapes which are socially and ecologically important in different ways. Among other interactions, shared use of rangelands by wildlife and livestock can lead to disease transmission. Understanding wildlife and livestock health and managing disease transmission in rangelands requires an integration of social and ecological knowledge. Using the example of Western Kazakhstan, home to two types of ungulate hosts, the critically endangered saiga antelopes, Saiga tatarica, and livestock, we conducted a cross‐scale analysis of social‐economic, ecological and climatic factors that contribute to transmission of diseases We focused on gastrointestinal nematodes (GINs) because they are transmitted between hosts that share pasture and they affect ungulate fitness. We used an interdisciplinary social–ecological methods approach which included conducting faecal egg counts of GINs in saigas and livestock, semi‐structured interviews and focus group discussions with livestock owners and herders in the region, and triangulation of information through secondary sources. Livestock rearing was done in two ways: (a) village‐based livestock and (b) outlying farms. The latter overlapped more with saigas. Village‐based livestock had significantly higher worm burdens than those on outlying farms, which had comparable burdens to saigas. Various factors exacerbate GIN prevalence and transmission: Veterinary services are minimal; both saiga and livestock numbers are increasing; and changing climate is increasing farmers' dependence on shared pastures for hay production. It will be crucial for saiga conservationists to engage in multi‐pronged conservation interventions, which are evaluated and adapted through the lens of rural livelihoods and the livestock health on which they depend. Our work provides researchers and practitioners with an avenue to better understand complex inter‐relationships and plan interventions within rangelands, while viewing host health from an interdisciplinary perspective—ultimately working towards wildlife conservation while safeguarding livelihoods across the world's rangelands. A free Plain Language Summary can be found within the Supporting Information of this article. A free Plain Language Summary can be found within the Supporting Information of this article.
... Entre los responsables de la declinación global de anfibios, las enfermedades han sido reconocidas como uno de los factores importantes en todo el mundo (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) . Los agentes etiológicos que las causan son numerosos y entre los más comunes podemos mencionar a los virus, bacterias, ácaros, gusanos, mohos y hongos. ...
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Parasitic infection represents an emerging threat to wild ungulates and a challenge to their management. Although a lot of work has been carried out on helminth parasitic infestation of domestic ungulates of Kashmir but the data pertaining to this aspect of wild ungulates has being ignored. The study on gastrointestinal helminth parasitic infestation of wild ungulates was carried out during post livestock grazing period (November to May) of 2018/2019 in Hirpora Wildlife sanctuary (HWLS) to fill the gap in the existing literature. During the study fresh faecal samples of musk deer Moschus sp . (n=44) and markhor Capra falconeri (n=41)were collected and examined qualitatively and quantitatively for gastrointestinal helminth parasites. A total of seven helminth parasites were recorded which are arranged in the descending order of their overall prevalence as Haemonchus spp . (44.70%), Nematodirus spp. (40%), Trichuris spp . (37.64%), Strongyloides spp . (34.11%) Trichostrongylus spp. (28.23%), Moniezia spp. (23.52%) and Fasciola spp. (20%). The mean EPG (eggs per gram) of different parasites showed a considerable variation in both the wild ungulates. The highest mean EPGwas that of Haemonchus spp. and the lowest mean EPG was that of Fasciola spp. in both hosts. A statistically significant difference was observed in the mean EPG of different parasites among two wild hosts (t=3.606, p=0.01 ).
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Diseases are natural regulating factors of wildlife populations, but some pathogens may become an important threat in wildlife conservation, especially for endangered species. The presence of domestic animals may foster the spread of diseases in natural population, although their role in the dynamic of infections in wildlife is not clear. In this study, we investigated the presence and prevalence of a range of multi-host pathogens in wild species (red fox, Eurasian badger, beech marten, pine marten, stoat for a total of 89 carcasses analysed) and domestic animals (n = 52 shepherd and n = 25 companion dogs) living in a protected area of the Alps (the Gran Paradiso National Park) and discussed the role of domestic dogs as possible source of infection for wild species. Our results showed that domestic dogs are potential shedder of three important pathogens: Canine distemper virus, Toxoplasma sp. and Neospora caninum. In particular, shepherd dogs seem to represent a threat for wildlife as they are exposed to multiple pathogens because of free-roaming, scavenging lifestyles and close proximity to livestock. However, also companion dogs more subject to veterinary care may foster the spread of pathogens. Our results highlight the importance of regulating the access of domestic dogs to protected areas that aim at preserving biodiversity and enhancing the conservation of endangered species.
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L’Albatros à nez jaune de l’océan indien (Thalassarche carteri) est une espèce menacée d’extinction dont la population principale, qui se reproduit sur l’île Amsterdam (Terres Australes et Antarctiques Françaises), connait un déclin et une très forte mortalité des jeunes individus depuis plusieurs décennies. La bactérie responsable du choléra aviaire, Pasteurella multocida, est suspectée comme étant à l'origine de ces mortalités et notre équipe évalue depuis plusieurs années maintenant l'utilisation d'un vaccin pour protéger les poussins, via leur vaccination directe, mais aussi celle des femelles reproductrices susceptibles de transmettre des anticorps protecteurs à leur poussin. Le vaccin utilisé est un vaccin autologue (autovaccin) spécifiquement développé par Ceva-Biovac contre une souche de la bactérie Pasteurella multocida isolée sur cadavre d’albatros. Suite à l’obtention de premiers résultats prometteurs, les objectifs de la thèse étaient d’ajuster le protocole de vaccination, mais également de mieux appréhender et décrire les processus éco-épidémiologiques en jeu au sein des populations de vertébrés de l’île Amsterdam. Ceci a reposé sur l'analyse fine du suivi de couples reproducteurs année après année, mais aussi sur l'utilisation de données éco-épidémiologiques expérimentales complémentaires, notamment une nouvelle formulation du vaccin. Une diversité de pathogènes responsables de mortalités a pu être caractérisée. L’âge optimal de vaccination des poussins parait être vers 10 jours et la vaccination des femelles reproductrices semble pouvoir protéger les poussins pendant plusieurs années, mais la forte densité de rats (Rattus norvegicus) actifs dans les colonies a rendu difficile l’identification d’un effet protecteur fort du vaccin. Les résultats obtenus améliorent la compréhension des mécanismes de circulation d'agents infectieux chez des espèces à reproduction coloniale et permettront de comparer les bénéfices relatifs attendus de différents scénarios de vaccination. Le travail montre l’importance d’intégrer des approches complémentaires, notamment du domaine biomédical et de l’écologie des populations, pour aborder la problématique de l’émergence de maladies infectieuses dans le contexte des changements environnementaux actuels.
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Background: Numerous Ebola virus outbreaks have occurred in Equatorial Africa over the past decades. Besides human fatalities, gorillas and chimpanzees have also succumbed to the fatal virus. The 2004 outbreak at the Odzala-Kokoua National Park (Republic of Congo) alone caused a severe decline in the resident western lowland gorilla (Gorilla gorilla gorilla) population, with a 95% mortality rate. Here, we explore the immediate genetic impact of the Ebola outbreak in the western lowland gorilla population. Results: Associations with survivorship were evaluated by utilizing DNA obtained from fecal samples from 16 gorilla individuals declared missing after the outbreak (non-survivors) and 15 individuals observed before and after the epidemic (survivors). We used a target enrichment approach to capture the sequences of 123 genes previously associated with immunology and Ebola virus resistance and additionally analyzed the gut microbiome which could influence the survival after an infection. Our results indicate no changes in the population genetic diversity before and after the Ebola outbreak, and no significant differences in microbial community composition between survivors and non-survivors. However, and despite the low power for an association analysis, we do detect six nominally significant missense mutations in four genes that might be candidate variants associated with an increased chance of survival. Conclusion: This study offers the first insight to the genetics of a wild great ape population before and after an Ebola outbreak using target capture experiments from fecal samples, and presents a list of candidate loci that may have facilitated their survival.
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Investigation of Batrachochytrium dendrobatidis prevalence in Columbia Spotted Frogs (Rana luteiventris) in Utah, and exploratory analysis of infection's impact on reproductive effort.
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Globally, anthrax outbreaks pose a serious threat to people, livestock, and wildlife. Furthermore, environmental change can exacerbate these outbreak dynamics by altering the host–pathogen relationship. However, little is known about how the quantitative spatial dynamics of host movement and environmental change may affect the spread of Bacillus anthracis, the causative agent of anthrax. Here, we use real‐time observations and high‐resolution tracking data from a population of common hippopotamus (Hippopotamus amphibius) in Tanzania to explore the relationship between river hydrology, H. amphibius movement, and the spatiotemporal dynamics of an active anthrax outbreak. We found that extreme river drying, a consequence of anthropogenic disturbances to our study river, indirectly facilitated the spread of B. anthracis by modulating H. amphibius movements. Our findings reveal that anthrax spread upstream in the Great Ruaha River (~3.5 km over a 9‐day period), which followed the movement patterns of infected H. amphibius, who moved upstream as the river dried in search of remaining aquatic refugia. These upstream movements can result in large aggregations of H. amphibius. However, despite these aggregations, the density of H. amphibius in river pools did not influence the number of B. anthracis‐induced mortalities. Moreover, infection by B. anthracis did not appear to influence H. amphibius movement behaviors, which suggests that infected individuals can vector B. anthracis over large distances right up until their death. Finally, we show that contact rates between H. amphibius‐ and B. anthracis‐infected river pools are highly variable and the frequency and duration of contacts could potentially increase the probability of mortality. While difficult to obtain, the quantitative insights that we gathered during a real‐time anthrax outbreak are critical to better understand, predict, and manage future outbreaks.
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The Anthropocene is a major threat to biodiversity worldwide. Human pressures including climate change and emerging infectious diseases are presenting new challenges to wildlife, requiring vigilance and monitoring of wild populations to ensure their persistence. In order to monitor fluctuations in health, baseline data from long-term studies are required. Clinical laboratory data on 80 black-and-white ruffed lemurs (Varecia variegata), derived from the capture of 98 individuals spanning six field seasons are presented. Serum biochemical profiles showed variation between years that remained within published reference intervals for the species, with the exception of total bilirubin in 2008, and creatine kinase and chloride in 2019. Serum trace minerals and fat-soluble vitamin values also fluctuated between years and are within ranges seen in other lemur species. These results, combined with previously published data on ectoparasite load and population genetic diversity, suggest that the Mangevo ruffed lemur population is healthy and can provide important and valuable baseline data for comparisons moving forward.
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Health is the most basic human right and one of the most important indicators of sustainable development. Individuals, communities and societies depend on healthy ecosystems support to remain healthy. Well-functioning ecosystems provide goods and services essential for human health. These goods and services include nutrition and food security, clean air and fresh water, medicines, cultural and spiritual values, and contributions to local livelihoods and economic development. They can also help to limit disease and stabilize the climate. However, over the years human activities have been constantly placing pressure on earth’s natural resources to meet the demands of the economies and the needs of a rapidly growing global population, which has resulted in the transformation of basic natural processes such as weather/climate, biogeochemical cycling, and more so the biological diversity in which the evolutionary changes depend. It is projected that less than 25% of Earth’s surface remains free from substantial impacts of human activities and the proportion is set to fall to a mere 10% or less by 2050. Constant human activities are resulting in soil, water and air pollution, increased emissions of greenhouse gases, deforestation and land use change, expanded urban areas, introduction of non-native species, and inadequately planned development of water and land resources to meet food and energy needs. These changes are having both direct and indirect impacts on our climate, ecosystems and biological diversity and human health. Thus, the integrated course of action that involves both individual and the government efforts must be instituted to tackle both human-induced drivers of biodiversity loss, disease emergence and the loss of ecosystem services that support health and general human well-being.
Article
Tropical forest degradation affects host-parasite interactions, determining the probability of animals acquiring an infection. The activation of an immune response to fight off infections requires energy and other resources such as antioxidants which may be redirected from growth and reproduction. A key question is how selective logging—the most common form of tropical forest degradation—impacts the prevalence of avian haemosporidian infection and its correlated physiological responses (nutritional and oxidative status markers). We investigated the prevalence of Plasmodium, Haemoproteus, and Leucocytozoon parasites in 14 understorey bird species in lowland, logged and unlogged, old-growth forests of Borneo. Prevalences of infections were similar between selectively logged and unlogged forests. To explore nutritional and oxidative status effects of haemosporidian infections, we examined associations between infections and plasma proteins, plasma triglycerides, and multiple blood-based markers of oxidative status, testing for an impact of selective logging on those markers. Birds infected with Plasmodium showed higher levels of plasma proteins and non-enzymatic antioxidant capacity, and lower levels of plasma triglycerides and glutathione, compared with haemosporidian-free individuals. Conversely, birds infected with Haemoproteus showed no changes in nutritional or physiological markers compared with uninfected individuals. These results indicate higher metabolic and physiological costs of controlling Plasmodium infection, compared with Haemoproteus, possibly due to higher pathogenicity of Plasmodium. Selectively logged forests had no effect on the responses of birds to infection, suggesting that the environmental conditions of degraded forests do not appear to induce any appreciable physiological demands in parasitised birds.
Thesis
Les microparasites eucaryotes sont une composante essentielle des écosystèmes, dont l’influence est considérable sur la dynamique des populations hôtes et le fonctionnement des réseaux trophiques. Le clade des Perkinsozoa (Alveolata), composé de quatre grands groupes parasitaires, en est un exemple représentatif en milieu marin. Certains de ces membres emblématiques, comme Perkinsus spp., représentent de réelles menaces écologiques et économiques en raison de leur caractère invasif, de leur pathogénicité et de leur grande plasticité phénotypique. L’objectif de cette thèse était de caractériser le rôle écologique et fonctionnel des Perkinsozoa d'abord à une échelle globale puis à une échelle populationnelle. Au sein de l’Océan globale, le groupe des Perkinsozoa est diversifié (109 ASVs – 6 clusters), peu abondant (<1%) et très localisé dans les communautés picoplanctoniques pélagiques. Un nouveau cluster actif, le Cluster A, a été mis en évidence dans la zone mésopélagique. Cependant, il est impossible de déterminer si ces Perkinsozoa putatifs sont symbiotiques ou libres car aucun d’eux n’a été caractérisé à ce jour. A l’échelle des populations, une méthodologie de PCR quantitative en temps réel en duplex a été élaborée pour l’étude in situ de la co-infection entre Perkinsus olseni et P. chesapeaki au sein d’une population de palourdes japonaises, R. philippinarum, dans le bassin d’Arcachon. Cette coinfection, répandue dans le bassin, représente 12 à 36 % des palourdes échantillonnées tandis que la monoinfection à P. olseni reste majoritaire. La présence sporadique de P. chesapeaki au sein de certains organes hôtes supposent que cette infection serait secondaire et pourrait être influencée par des paramètres environnementaux jouant sur les stades du cycle de vie parasitaire. Dans un contexte global d’émergence des maladies, une vision intégrative des relations hôtes-parasites est nécessaire pour résoudre le rôle écologique des Perkinsozoa dans différents écosystèmes.
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Onchocercidae nematodes are heteroxenous parasites with worldwide distribution, and some of the species associated to animals may present zoonotic potential. Climatic changes and anthropic influences on the environment may result in vectors’ proliferation, facilitating the spillover to humans and/or non-typical animal hosts. The Iguaçu National Park (PARNA Iguaçu), one of the most important Brazilian natural remanescents of Atlantic rainforest, is strongly affected by human activities such as tourism and agriculture. The complexity of this area is especially characterized by the close nexus between the rich wildlife, humans, and domestic animals, especially domestic dogs. Based on this, this research aimed to diagnose the Onchocercidae nematodes in wild carnivores and domestic dogs in the PARNA Iguaçu and the surrounding areas. For this, we collected 162 samples of seven species of wild carnivores and 225 samples of domestic dogs. The presence of microfilariae in the blood samples was diagnosed by the modified Knott’s test and molecular screening, and the specific identification was based on sequencing of the myoHC and hsp70 genes. Microfilariae were detected only in ring-tailed coatis, in which we found five species: Mansonella sp. 1, Mansonela sp. 2, Onchocercidade gen. sp. 1, Onchocercidade gen. sp. 2, and Dirofilaria immitis . The morphological analysis supported the molecular findings. The domestic dogs were parasitized by Acanthocheilonema reconditum , representing a new locality record for this species. Phylogenetic analysis showed high genetic similarity among the four undetermined species and Mansonella spp., Brugia spp., and Wuchereria bancrofti . The presence of D . immitis in ring-tailed coatis may be result of spillover from dogs, even though the parasite was not diagnosed in the sampled dogs. The presence of several undetermined Onchocercidae species indicates the necessity of continuous investigations on wild and domestic animals from Neotropical area, especially considering the growing anthropic influence on forest remnants.
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Emerging infectious diseases are significant threats to wildlife conservation, yet the impacts of pathogen exposure and infection can vary widely among host species. As such, conservation biologists and disease ecologists have increasingly aimed to understand species‐specific host susceptibility using molecular methods. In particular, comparative gene expression assays have been used to contrast the transcriptomic responses of disease‐resistant and disease‐susceptible hosts to pathogen exposure. This work usually assumes that the gene expression responses of disease‐resistant species will reveal the activation of molecular pathways contributing to host defense. However, results often show that disease‐resistant hosts undergo little gene expression change following pathogen challenge. Here, we discuss the mechanistic implications of these “null” findings and offer methodological suggestions for future molecular studies of wildlife disease. First, we highlight that muted transcriptomic responses with minimal immune system recruitment may indeed be protective for non‐susceptible hosts if they limit immunopathology and promote pathogen tolerance in systems where susceptible hosts suffer from genetic dysregulation. Second, we argue that overly narrow investigation of responses to pathogen exposure may overlook important, constitutively active molecular pathways that underlie species‐specific defenses. Finally, we outline alternative study designs and approaches that complement interspecific transcriptomic comparisons, including intraspecific gene expression studies and genomic methods to detect signatures of selection. Collectively, these insights will help ecologists extract maximal information from conservation‐relevant transcriptomic datasets, leading to a deeper understanding of host defenses and, ultimately, the implementation of successful conservation interventions.
Article
The 48 described species of parasitic and non-parasitic lamprey within the order Petromyzontiformes span much of the globe. Although the sea lamprey (Petromyzon marinus) is an unwanted invasive in the Laurentian Great Lakes, most lamprey species are of ecological and cultural value, and of conservation concern. Infectious diseases affect fish health, growth, reproduction, and recruitment; yet, the impact of pathogens that cause them in lamprey have not been comprehensively assessed. This review collates existing information to gain a better understanding of pathogen distribution in lamprey populations. At least 46 genera of parasites, seven genera of bacteria, two genera of fungi and oomycetes, and two viruses belonging to two families have been documented to occur in lamprey, most of which have also been identified in other fish species. Many pathogens of lamprey have not been described completely. Moreover, many details of the host-pathogen interactions in lamprey remain unknown, leaving links between pathogens and disease causation unclear. This knowledge gap is extended by the lack of studies on lamprey immune systems, nor have Koch’s or Rivers’ postulates for most lamprey pathogens been fulfilled. Designing future studies aimed at addressing these knowledge shortfalls will not only clarify the effects that infectious diseases have on imperiled lamprey populations, but also contribute to assessments of potential biocontrol for invasive lamprey populations in the future.
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River dolphins are a highly threatened polyphyletic group comprised of four odontocete families: Iniidae, Pontoporiidae, Lipotidae, and Platanistidae, the first two endemic to South America. To address the knowledge gap regarding infectious agents in this cetacean group, we surveyed the presence of herpesviruses by PCR in skin and/or blood samples of live-captured Amazon (Inia geoffrensis, n = 25) and Bolivian (Inia boliviensis, n = 22) river dolphins of the Amazon basin and in selected tissue samples of franciscanas (Pontoporia blainvillei, n = 27) stranded or bycaught in southeastern Brazil. Additionally, available franciscana tissue samples were examined by histopathology. Herpesvirus DNA was amplified in 13 Bolivian river dolphins (59.1%, 95% CI 38.5–79.6%) and 14 franciscanas (51.9%, 95% CI 33.0–70.7%). All Amazon river dolphins were herpesvirus-negative. Two different herpesviruses were found in Bolivian river dolphins: a previously known gammaherpesvirus detected in blood and/or skin samples of all positive individuals and a novel alphaherpesvirus in the skin of one animal. A new gammaherpesvirus was found in several franciscana samples—the first herpesvirus recorded in Pontoporiidae. Intranuclear inclusion bodies consistent with herpesvirus were observed in the lymph node of one franciscana. The high divergence among the obtained herpesviruses and those previously described can be explained by viral-host coevolution, and by the fact that these populations are fairly isolated.
Article
Parasites that infect multiple species cause major health burdens globally, but for many, the full suite of susceptible hosts is unknown. Predicting undocumented host‐parasite associations will help expand knowledge of parasite host specificities, promote the development of theory in disease ecology and evolution, and support surveillance of multi‐host infectious diseases. Analysis of global species interaction networks allows for leveraging of information across taxa, but link prediction at this scale is often limited by extreme network sparsity and lack of comparable trait data across species. Here we use recently developed methods to predict missing links in global mammal parasite networks using readily available data: network properties and evolutionary relationships among hosts. We demonstrate how these link predictions can efficiently guide the collection of species interaction data and increase the completeness of global species interaction networks. We amalgamate a global mammal host‐parasite interaction network (>29,000 interactions) and apply a hierarchical Bayesian approach for link prediction that leverages in formation on network structure and scaled phylogenetic distances among hosts. We use these predictions to guide targeted literature searches of the most likely yet undocumented interactions, and identify empirical evidence supporting many of the top “missing” links. We find that link prediction in global host‐parasite networks can successfully predict parasites of humans, domesticated animals, and endangered wildlife, representing a combination of published interactions missing from existing global databases, and potential but currently undocumented associations. Our study provides further insight into the use of phylogenies for predicting host‐parasite interactions, and highlights the utility of iterated prediction and targeted search to efficiently guide the collection of information on host‐parasite interactions. These data are critical for understanding the evolution of host specificity, and may be used to support disease surveillance through a process of predicting missing links, and targeting research towards the most likely undocumented interactions.
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El objetivo principal de este Manual es el desarrollo de un compendio de técnicas y protocolos estándares para el inventario y monitoreo de poblaciones de anfibios, actualizado con los procedimientos, herramientas y técnicas de análisis más recientes y adaptado a las condiciones y realidades nacionales. Su contenido está destinado a ayudar a superar algunas de las dificultades que se pueden enfrentar al configurar un programa de inventario y monitoreo para anfibios. Pretendemos brindar una orientación práctica sobre cómo diseñar y llevar a cabo estudios que puedan servir para múltiples aplicaciones más allá de las necesidades de un proyecto particular. En este manual compilamos las experiencias y consejos de numerosos especialistas sobre diferentes temáticas que pudieran permitir a los lectores y usuarios de este manual obtener la mayor cantidad y calidad de datos durante la realización de futuros proyectos de investigación relacionados con estas temáticas.
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Chytridiomycosis is an emerging disease responsible for global decline and extinction of amphibians. We report the causative agent, Batrachochytrium dendrobatidis, in North American bullfrogs (Rana catesbeiana) farmed for the international restaurant trade. Our findings suggest that international trade may play a key role in the global dissemination of this and other emerging infectious diseases in wildlife.
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Amphibian declines have been reported from around the world. Here we examine life history and distributional characteristics of Australian frogs listed as threatened under the IUCN Global Amphibian Assessment guidelines, and compare these results to available information on threatened amphibians around the world. Forty of 213 Australian frog species (18.8%) are currently recognised as threatened. While eight species are listed as Vulnerable due to small or restricted populations alone (VU D2), the remaining 32 species are associated with population declines. Threatened species are concentrated in upland areas (41% of all upland species are threatened, while only 8% of lowland species are threatened). Twenty-eight of the 40 threatened species (70%) primarily occur in upland areas while only 42 of the 173 non-threatened species (24.3%) occur in upland areas. Restricted geographic range is characteristic of 31 of 40 threatened/declining species (77.5%). However, 41 non-threatened species (23.7%) also have restricted geographic ranges. Latitudinal position is not strongly associated with the degree of threat. Threatened species are strongly associated with specific reproductive habitats: 80% of species occurring in montane wetlands and 58% of species breeding in wet forest streams are threatened. For 22 of the 40 (55%) threatened species, known threats do not adequately explain the extent of decline. Habitat modification is the foremost threatening process associated with declines in 20 of the 40 threatened species (50%), including 11 of 12 threatened lowland species (91.7%). Chytrid fungus is notably associated with declines for five species and a potential contributor for an additional nine species (35% of threatened species). However, the chytrid has also been detected in an additional 33 non-threatened species (19%). Minor threats associated with threatened species include fire and global changes in weather patterns. Phylogenetic relationships of Australian frogs are poorly resolved, and there are no strong associations between phylogeny and declines within known taxonomic groups. A notable exception are frogs of the myobatrachid genus Taudactylus where five of the six species are threatened. Global patterns are difficult to assess, however, as declines are strongly associated with species that are primarily distributed in upland areas. Chytrid fungus has been found in both declining and non-declining species throughout Australia, and while its role as an emerging infectious disease is currently under investigation (in Australia, New Zealand, Spain, South Africa, Costa Rica, Ecuador and the USA), little is known about its distribution and prevalence in other countries.
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Emerging infectious diseases may be contributing to the global decline of amphibian populations. In particular, chytridiomycosis, a cutaneous fungal infection of amphibians caused by the chytrid Batrachochytrium dendrobatidis, gained attention in the 1990s as an apparently new pathogen. This fungus has been implicated as the causative agent of widespread mortalities among wild amphibians in geographically disparate parts of the world. To investigate the global distribution, historical occurrence, and infectiousness of this pathogen, we examined 3371 postmetamorphic and adult amphibians collected between 1895 and 2001 from 25 countries for the presence of chytrid fungi in the epidermis. Cutaneous chytrid infection was diagnosed in 383 of 2931 (13.1%) specimens of 12 common amphibian species from five Canadian provinces and seven American states, including 30 of 69 locations examined in the St. Lawrence River Valley of Québec. Chytrids were observed in 7.0% (46/655) of the adults collected in the 1960s, the earliest cases being two green frogs ( Rana clamitans) collected in 1961 from Saint-Pierre-de-Wakefield, Québec. In recent studies, morbidity and mortality attributable to chytridiomycosis were not observed in infected amphibians from Québec despite a 17.8% (302/1698) prevalence of chytrid infection during the period 1990–2001. The prevalence of infection during this latter period was not statistically different when compared with the period 1960–1969. Epidermal chytrid infections were not observed in 440 amphibians examined from 23 other countries. In light of the fact that infection by B. dendrobatidis is widely distributed and apparently enzootic in seemingly healthy amphibians from eastern North America, lethal outbreaks of chytridiomycosis among amphibian populations appear to have complex causes and may be the result of underlying predisposing factors.
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Disease is a growing concern in conservation biology. Alteration to habitats can favor intermediate hosts such as mosquitoes. Stress may increase susceptibility to infectious disease. Alterations to trophic cascades can indirectly favor the emergence of diseases on those species that increase in abundance. Most notably, pathogen pollution, by introduced species. can expose hosts to diseases for which they have no coevolved resistance. These effects can impair conservation by making formerly common species rare or inhibiting rare species from recovering. In addition, managing wildlife diseases can have undesirable environmental impacts. Because conservation biology focuses on threats, Iess attention has been paid to the concept that envi­ronmental change will lead to declinces in disease. Because the spread, persistence. and impact of infectious diseases tend to increse with host density. rare species of concern should suffer less from host-specific infectious disease than common species. Parasites may themselves be sensitive to environmental change and suffer direct mortality or interruption of life cycles. This loss of disease may be of concern in instances where diseases are important for biodiversity. A lack of disease may allow common species (and particularly introduced species) to exclude rare species. A loss of trophically transmitted parasites may impair predators. In conclusion. environmental change will hamper some diseases and favor others in ways that may be of substantial concern for conservation biology.
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Epidermal changes caused by a chytridiomycete fungus (Chytridiomycota; Chytridiales) were found in sick and dead adult anurans collected from montane rain forests in Queensland (Australia) and Panama during mass mortality events associated with significant population declines. We also have found this new disease associated with morbidity and mortality in wild and captive anurans from additional locations in Australia and Central America. This is the first report of parasitism of a vertebrate by a member of the phylum Chytridiomycota. Experimental data support the conclusion that cutaneous chytridiomycosis is a fatal disease of anurans, and we hypothesize that it is the proximate cause of these recent amphibian declines.
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Alford et al. question the working model underlying our test for a link between global warming and amphibian disappearances, and Di Rosa et al. criticize our emphasis on a single proximate agent, the chytrid fungus Batrachochytrium dendrobatidis. Both teams report key pieces of the amphibian-decline puzzle and new evidence from different parts of the world that climate change is a factor in these losses. Here we show why our working model was appropriate and highlight the complexity of the imminent threat to species survival that results as global warming conspires with various other agents.
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Page 1. ABOfH The of Stuart L. Pimm,* Gareth J. Russell, John L. Gittleman, Thomas M. Brooks against which to
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Host–pathogen models are essential for designing strategies for managing disease threats to humans, wild animals and domestic animals. The behaviour of these models is greatly affected by the way in which transmission between infected and susceptible hosts is modelled. Since host–pathogen models were first developed at the beginning of the 20th century, the ‘mass action’ assumption has almost always been used for transmission. Recently, however, it has been suggested that mass action has often been modelled wrongly. Alternative models of transmission are beginning to appear, as are empirical tests of transmission dynamics.
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Chytridiomycosis is an emerging fungal disease of amphibians responsible for mass mortalities and population declines globally. One hypothesis for its recent emergence is anthropogenic introduction of the causative agent Batrachochytrium dendrobatidis through trade in amphibians for pets, food and biocontrol. In this study, we examined histological samples from apparently healthy American bullfrogs Rana catesbeiana that have been introduced into the Venezuelan Andes. B. dendrobatidis was present in 96% (46/48) of the individuals examined. In contrast to cases of chytridiomycosis outbreaks, the majority (44/46) of frogs had few, small lesions consistent with little or no clinical disease and no unusual mortality was observed. These findings have implications for amphibian declines in Venezuela and elsewhere. First, the high prevalence of Batrachochytrium but lack of clinical signs or chytridiomycosis-related mortality suggests that R. catesbeiana may be a good reservoir for this parasite in Venezuela. Second, the presence of this emerging pathogen in an introduced amphibian species suggests that trade and introduction of amphibians should be monitored and controlled to halt the spread of this pathogen nationally and internationally.
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Parasites are important determinants of ecological dynamics. Despite the widespread perception that parasites (in the broad sense, including microbial pathogens) threaten species with extinction, the simplest deterministic models of parasite dynamics (i.e. of specialist parasites with density-dependent transmission) predict that parasites will always go extinct before their hosts. We review the primary theoretical mechanisms that allow disease-induced extinction and compare them with the empirical literature on parasitic threats to populations to assess the importance of different mechanisms in threatening natural populations. Small pre-epidemic population size and the presence of reservoirs are the most commonly cited factors for disease-induced extinction in empirical studies.
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An emerging infectious facial cancer threatens Tasmanian devils with extinction. The disease is likely to occur across the range of the devil within 5 years. This urgent time frame requires management options that can be implemented immediately: the establishment of insurance populations, in captivity, wild-living on islands, and aiming for eradication in areas that can be isolated. The long-term options of the spontaneous or assisted evolution of resistance or development of a field-deliverable vaccine are unlikely to be available in time. The disease's characteristic allograft transmission through intimate contact simplifies isolation of insurance populations and breaking transmission in suppression trials. Better knowledge of contact matrices in wild devils will help focus timing and demographic targets of removals. A metapopulation approach is needed that integrates captive and wild-living island and peninsula (disease suppression) populations to minimize the loss of genetic diversity over 50 years until either extinction and reintroduction can occur, resistance evolves or a field-deliverable vaccine is developed. Given the importance of the insurance populations and the low genetic diversity of devils, a conservative target for retention of 95% genetic diversity is recommended. Encouraging preliminary results of the first disease-suppression trial on a large peninsula show fewer late stage tumors and no apparent population decline. Limiting geographic spread or suppressing the disease on a broadscale are both unlikely to be feasible. Since the synergy of devil decline and impending fox establishment could have devastating consequences for Tasmanian wildlife, it is crucial to manage the dynamics of new and old predator species together. Yes Yes
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Biological invasions cause billions of dollars in economic damage each year and are a serious threat to native biodiversity. Introduced animals and plants may escape 75% or more of the parasite and pathogen species from their native range. While they do accumulate novel parasite species from their new location, this number is generally only a fraction of the number lost. Individual plants and animals are also generally less frequently infected (prevalence minus percent individuals infected) in introduced compared to native conspecific populations. In conjunction with other biological and physical factors, release from parasites helps explain the increased demographic performance of invasive species, potentially accounting for much of the damage they cause.
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Biologists are nearly unanimous in their belief that humanity is in the process of extirpating a significant portion of the earth's spe­ cies. The ways in which we are doing so reflect the magnitude and scale of human enterprise. Everything from highway construction to cattle ranch­ ing to leaky bait buckets has been implicated in the demise or endan­ germent of particular species. Ac­ cording to Wilson (1992), most of these activities fall into four major categories, which he terms "the mind­ less horsemen of the environmental apocalypse": overexploitation, habi­ tat destruction, the introduction of non-native (alien) species, and the spread of diseases carried by alien species. To these categories may be added a fifth, pollution, although it can also be considered a form of habitat destruction. Surprisingly, there have been reIa­ tively few analyses of the extent to which each of these factors-much less the more specific deeds encomDavid S. Wilcove is a senior ecologist at the Environmental Defense Fund, Wash­ ington, DC 20009. David Rothstein re­ ceived his J.D. in 1997 from Northeastern
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Getz and Pickering (1983) demonstrated that density-dependent population regulation due to factors other than the disease can lead to host-pathogen coexistence when there is frequency-dependent transmission. The authors here explore the Getz-Pickering model further, focusing on the case in which nondisease density-dependent factors act more severely on healthy than on diseased classes. Such differential density dependence is likely to be characteristic of sexually transmitted diseases in which population regulation is by density dependence acting primarily on the juvenile stage. Under such situations (and assuming only horizontal disease transmission) recruitment into the healthy class will be density-dependent, but recruitment into the diseased class will be density-independent because, almost by definition, sexual transmission occurs only in the adult phase. -from Authors
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2 Biological invasions cause billions of dollars in economic damage each year and are a serious threat to native biodiversity. Introduced animals and plants may escape 75% or more of the parasite and pathogen species from their native range. While they do accumulate novel parasite species from their new location, this number is generally only a fraction of the number lost. Individual plants and animals are also gener- ally less frequently infected (prevalence minus percent individuals infected) in introduced compared to native conspecific populations. In conjunction with other biological and physical factors, release from parasites helps explain the increased demographic performance of invasive species, potentially accounting for much of the damage they cause.
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IntroductionThe MiteLife HistoryDistribution, Epidemiology, and TransmissionClinical SignsPathogenesis and PathologyDiagnosisImmunologyControl and TreatmentPublic Health ConcernsLiterature Cited
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Parasites are thought to provide a selective force capable of promoting genetic variation in natural populations. One rarely considered pathway for this action is via parasite-mediated selection against inbreeding. If parasites impose a fitness cost on their host and the offspring of close relatives have greater susceptibility to parasites due to the increased homozygosity that results from inbreeding, then parasite-mediated mortality may select against inbred individuals. This hypothesis has not yet been tested within a natural vertebrate population. Here we show that relatively inbred Soay sheep (Ovis aries), as assessed by microsatellite heterozygosity, are more susceptible to parasitism by gastrointestinal nematodes, with interactions indicating greatest susceptibility among adult sheep at high population density. During periods of high overwinter mortality on the island of Hirta, St. Kilda, Scotland, highly parasitised individuals were less likely to survive. More inbred individuals were also less likely to survive, which is due to their increased susceptibility to parasitism, because survival was random with respect to inbreeding among sheep that were experimentally cleared of their gastrointestinal parasite burden by anthelminthic treatment. As a consequence of this selection, average microsatellite heterozygosity increases with age in St. Kildan Soay sheep. We suggest that parasite-mediated selection acts to maintain genetic variation in this small island population by removing less heterozygous individuals.
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Infectious disease can be a concern for several aspects of conservation biology, such as determining threats to species, estimating population viability, and designing reserves, captive breeding, and recovery programs. Several measures are useful for describing infectious diseases in host populations, but it is not straightforward to determine the degree to which a particular disease may affect a host population. The most basic epidemiological theory suggests that populations should be least subject to host-specific infectious disease when they are at low abundance ( paradoxically, the state at which they are in most need of conservation action). There are important exceptions, however, such as when a reservoir host exists or when Allee or stochastic effects occur. Several of the key threats to biodiversity—habitat alteration, introduced species, pollution, resource exploitation, and climate change—can facilitate and/or impair transmission of infectious disease. Common management tools such as population viability analysis rarely address infectious disease explicitly. We suggest that such an inclusion is both possible and warranted. Considerations of infectious disease may influence the way we determine whether a spec