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Abstract

The distribution of the chytrid fungus Batrachochytrium salamandrivorans continues to expand in Europe. During 2014-2018, we collected 1,135 samples from salamanders and newts in 6 countries in Europe. We identified 5 cases of B. salamandrivorans in a wild population in Spain but none in central Europe or the Balkan Peninsula.
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Address for correspondence: Fang Huang, Beijing Center for Disease
Prevention and Control, Institute for Communicable Disease Control
and Prevention, No. 16, Hepingli Middle Av, Dongcheng District,
Beijing 100013, China; email: hhxdd@126.com
Recent Findings of Potentially
Lethal Salamander Fungus
Batrachochytrium
salamandrivorans
David Lastra González, Vojtech Baláž,
Milič Solský, Barbora Thumsová,
Krzysztof Kolenda, Anna Najbar,
Bartłomiej Najbar, Matej Kautman, Petr Chajma,
Monika Balogová, Jiří Vojar
Author aliations: Czech University of Life Sciences, Prague,
Czech Republic (D. Lastra González, M. Solský, B. Thumsová,
P. Chajma, J. Vojar); University of Veterinary and Pharmaceutical
Sciences, Brno, Czech Republic (V. Baláž, M. Kautman);
University of Wrocławski, Wroclaw, Poland (K. Kolenda,
A. Najbar); University of Zielona Góra, Lubuskie, Poland
(B. Najbar); Slovak Academy of Sciences, Košice, Slovakia
(M. Kautman); Pavol Jozef Šafárik University in Košice, Košice
(M. Balogová)
DOI: https://doi.org/10.3201/eid2507.181001
The distribution of the chytrid fungus Batrachochytrium
salamandrivorans continues to expand in Europe. During
2014–2018, we collected 1,135 samples from salamanders
and newts in 6 countries in Europe. We identied 5 cases of
B. salamandrivorans in a wild population in Spain but none
in central Europe or the Balkan Peninsula.
Chytridiomycosis, an amphibian disease caused by the
chytrid fungi Batrachochytrium dendrobatidis and B.
salamandrivorans, is responsible for declines of amphib-
ian populations worldwide (1). The recently discovered B.
salamandrivorans (2) is severely impacting salamanders
and newts in Europe (3,4). This emerging fungal pathogen
infects the skin of caudates and causes lethal lesions (2). It
most likely was introduced to Europe by the pet salamander
trade from Southeast Asia (3). In Europe, the Netherlands,
Belgium, and Germany have conrmed B. salamandriv-
orans in wild caudates; the United Kingdom, Germany,
and Spain have conrmed the fungus in captive animals
(5,6). Several countries have established trade regulations
(5) and a recent European Union decision, no. 2018/320,
implements measures to protect against the spread of B.
salamandrivorans via traded salamanders (7). The World
Organisation for Animal Health listed infection with B.
salamandrivorans as a notiable disease in 2017. In ad-
dition to controlling the amphibian pet trade, surveillance
of the pathogen is urgently needed to establish disease in-
tervention strategies in aected areas and prevention in B.
salamandrivorans–free regions.
During 2014–2018, we collected 1,135 samples directly
for the detection of B. salamandrivorans or as a part of unre-
lated studies. Samples came from 10 amphibian species at 47
sites in 6 countries in Europe. Most samples came from the
re salamander, Salamandra salamandra, which is a known
suitable host for B. salamandrivorans (3), and the palmate
newt, Lissotriton helveticus, which is known to be resistant
to B. salamandrivorans (Appendix Table 1, http://wwwnc.
cdc.gov/EID/article/25/7/18-1001-App1.pdf).
Most samples were skin swabs collected by following
the standard procedure for sampling of amphibian chytrid
fungi (8). A smaller portion of samples was toe clippings
(Appendix Table 2). We extracted genomic DNA following
the protocol of Blooi et al. (9), and 2 laboratories with dif-
ferent equipment tested for B. salamandrivorans. Samples
from Spain and the Czech Republic initially were analyzed
at the Czech University of Life Sciences (Prague, Czech
1416 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 25, No. 7, July 2019
RESEARCH LETTERS
Republic) by standard PCR with B. salamandrivorans
specic primers STerF and STerR, as described by Martel
et al. (2), with subsequent electrophoresis on the ampli-
ed target. We reanalyzed samples that produced positive
or equivocal results by using duplex quantitative PCR
(qPCR) for B. dendrobatidis and B. salamandrivorans (9)
at the University of Veterinary and Pharmaceutical Scienc-
es (Brno, Czech Republic). Trenton Garner of the Institute
of Zoology, Zoological Society of London (London, Eng-
land), provided DNA for quantication standards of the B.
dendrobatidis GPL lineage, strain IA042, and An Martel
of Ghent University (Ghent, Belgium) provided quantica-
tion standards of B. salamandrivorans.
We directly analyzed samples from other countries by
qPCR. We used negative and positive controls for standard
PCR analyses and quantication standards for qPCR analy-
ses. For B. dendrobatidis– or B. salamandrivorans–posi-
tive sites, we estimated prevalence and Bayesian 95% CIs
using 3 parallel Markov chains with 2,000 iterations each,
a burn-in of 1,000 iterations, and no thinning (Appendix
Table 1). We performed all statistical analyses in R 3.3.1
using the R2WinBUGS package and WinBUGS 1.4.3 (10).
Samples from 5 L. helveticus newts tested positive
for B. salamandrivorans, implying that this species is
not resistant to this fungus as previously indicated by ex-
perimental exposures (3). The positive cases were found
in populations from an isolated area encompassing 2 dif-
ferent regions in northern Spain, Cantabria and Asturias,
with remote human populations. Four cases were found in
livestock drinking troughs located 150–1,000 m above sea
level, and 1 case was found in a pond in a private garden,
30 km from the nearest recorded case. We did not nd B.
salamandrivorans–positive cases in consecutive locations
during our monitoring.
Although B. salamandrivorans cases have been re-
ported in captive salamanders (6), our reported cases were
>1,000 km from any area of known B. salamandrivorans
occurrence (7). We also detected B. dendrobatidis by du-
plex qPCR in 11 samples from 3 newt species (L. helve-
ticus, L. vulgaris, and Triturus cristatus) from Spain and
Montenegro and 1 captive Cynops ensicauda newt from the
Czech Republic. The B. dendrobatidis–positive cases did
not involve co-infection with B. salamandrivorans.
We conrmed that the known distribution of B. sala-
mandrivorans continues to expand in Europe, indicating
that this fungus might be capable of dispersing over long
distances (4), might be introduced by humans, or might
even have been circulating in this geographic range with
no detected deaths. Our results should alert the research
and conservation community and motivate urgent action to
identify regions with early emergence of the disease and
implement mitigation measures to prevent further spread
of this deadly pathogen.
Acknowledgments
We thank the Cantabria delegation of SEO/Birdlife; Fundación
Zoo Santillana del Mar; workers from Marismas de Santoña,
Victoria y Joyel Natural Park, with special thanks to
Carlos Rubio; Pepo Nieto, Pedro Barreda, and his family;
Elena Kulikova and Wiesław Babik; and also our friends
Daniel Koleška, Kamila Šimůnková, Tomáš Holer, and
Daniela Budská for eldwork.
This work was performed with permission from the Nature
Conservation Agency of the Czech Republic; Agency for Nature
and Environment Protection of Montenegro permit no. 02 Broj
UPI–321/4; Ministry of Environment of the Slovak Republic,
permit no. 4924/2017–6.3; the Endangered Species Section of
Environmental Service of Cantabria, Spain, permit no. EST–
419/2017–SEP; the Environmental Service of Castilla y León,
Spain, permit no. EP/LE/233/2017; Department of Nature
Conservation of Poland, permit nos. DZP-WG.6401.02.7.2014.
JRO, WPN.6401.211.2015.MR.2, 78/2014, and 68/2015; the
Ministry of Protection of Environment of Croatia, permit no.
UP/I–612–07/169–48/68; and agreements from other agencies,
including Red Cambera, special thanks to Sergio Tejón and Tomás
González; Fondo para la Protección de los Animales Salvajes; and
Fundación Naturaleza y Hombre, Spain. The study was supported
by the Czech University of Life Sciences, Prague, Czech Republic
(grant nos. 20174218 and 20184247) and the Internal Grant
Agency of the University of Veterinary and Pharmaceutical
Sciences, Brno, Czech Republic (grant no. 224/2016/FVHE).
K.K. was supported by MNiSW grant for Young Scientists no.
0420/1408/16; A.N. was supported by grant no. DS 1076/S/
IBŚ/2014 and MNiSW grant for Young Scientists no. 0420/1409/16.
About the Author
Mr. Lastra González is a PhD candidate at Czech University
of Life Sciences, Prague. His research focuses on amphibian
conservation and emerging infectious diseases that aect them.
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Address for correspondence: David Lastra González, Faculty of
Environmental Sciences, Czech University of Life Sciences,
Kamýcká 129, 165 21 Prague–Suchdol, Czech Republic;
email: lastra_gonzalez@fzp.czu.cz
Crimean-Congo Hemorrhagic
Fever Virus Genome in Tick
from Migratory Bird, Italy
Elisa Mancuso, Luciano Toma, Andrea Polci,
Silvio G. d’Alessio, Marco Di Luca,
Massimiliano Orsini, Marco Di Domenico,
Maurilia Marcacci, Giuseppe Mancini,
Fernando Spina, Maria Goredo,
Federica Monaco
Author aliations: Istituto Zooprolattico Sperimentale
dell’Abruzzo e del Molise “G. Caporale,” Teramo, Italy
(E. Mancuso, A. Polci, S.G. d’Alessio, M. Orsini,
M. Di Domenico, M. Marcacci, G. Mancini, M. Goredo,
F. Monaco); Istituto Superiore di Sanità, Rome, Italy (L. Toma,
M. Di Luca); Istituto Superiore per la Protezione e la Ricerca
Ambientale, Bologna, Italy (F. Spina)
DOI: https://doi.org/10.3201/eid2507.181345
We detected Crimean-Congo hemorrhagic fever virus in a
Hyalomma rupes nymph collected from a whinchat (Saxi-
cola rubetra) on the island of Ventotene in April 2017. Partial
genome sequences suggest the virus originated in Africa.
Detection of the genome of this virus in Italy conrms its
potential dispersion through migratory birds.
Crimean-Congo hemorrhagic fever virus (CCHFV) is a
vectorborne virus responsible for severe illness in hu-
mans, whereas other mammals usually act as asymptomatic
reservoirs. The virus is transmitted through tick bites or by
direct contact with blood or body uids of infected verte-
brate hosts. CCHFV, an Orthonairovirus within the Nairo-
viridae family, has a negative-sense tripartite RNA genome
characterized by high genetic diversity. The sequences of
the circulating strains cluster in 6 genotypes (I–VI) reect-
ing their geographic origin; worldwide distribution is the
result of ecient dispersion through migratory birds, hu-
man travelers, and the trade and movement of livestock and
wildlife (1,2). In Europe, CCHFV distribution was limited
to the Balkan region until 2010, when the virus was iden-
tied in ticks collected from a red deer (Cervus elaphus)
and, 6 years later, in 2 autochthonous human cases in the
same region of Spain (3). Sequences from the Iberia strains
clustered in the Africa genotype III (4), supporting the hy-
pothesis of CCHFV dispersion through ticks hosted by mi-
grating birds.
The role of birds in the potential spread of the virus
was conrmed by CCHFV detection in ticks collected from
migratory birds in Greece in 2009 (5) and Morocco in 2011
(6). Because Italy hosts an intense passage of birds migrat-
ing along major routes connecting winter quarters in Africa
and breeding areas in Europe, the country is potentially
exposed to the risk for virus introduction. We report the
detection of CCHFV RNA in a tick collected in Italy from
a migratory bird.
We conducted tick sampling during March–May 2017
on the island of Ventotene, where a ringing station has been
operating since 1988 as part of the Small Islands Project, a
large-scale and long-term eort to monitor spring migra-
tions of birds across the central and western Mediterranean.
We ringed 5,095 birds and checked 80% for ectoparasites.
We collected 14 adults, 330 nymphs, and 276 larvae from
268 passerines belonging to 28 species; 18 species were
trans-Saharan migrants. We stored ticks in 70% ethanol
until morphologic identication and assignment to a genus
or, whenever possible, a species (7). We then individually
1418 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 25, No. 7, July 2019
RESEARCH LETTERS
... Since its discovery, the pathogen has also been found in the wild in Germany and in several Asian countries Laking et al. 2017, Yuan 2017, and there is evidence that it is expanding its range in Europe (Spitzen-van der Sluijs et al. 2016). Recently, it was also reported in Spain by two independent research groups in different regions of the country (Lastra González et al. 2019;Martel et al. 2020). ...
... In response to the threat that Bsal poses, research efforts focusing on this new pathogen have intensified, foremost in Europe. Studies have revealed which species are being affected by Bsal and how it is spreading (e.g., Spitzenvan der Sluijs et al. 2016;Lastra González et al. 2019). This research is complemented by monitoring studies in locations where Bsal is yet to be detected (e.g., Parrot et al. 2017;Waddle et al. 2020). ...
... This can cause problems, as researchers might not be aware of all available information, and decision-makers might not be able to react on time. For example, the first field report of Bsal detection in Spain (Lastra González et al. 2019) was neither cited nor discussed when the pathogen was re-discovered in Spain later on . Now, almost ten years after Bsal was first reported, we believe it is useful to compile and review the available information. ...
Article
Full-text available
Batrachochytrium salamandrivorans (Bsal), a species related to the destructive pathogen Batrachochytrium dendrobatidis (Bd), was found and identified in Europe in 2013. Now, a decade later, a large amount of information is available. This includes data from studies in the field, reports of infection in captive amphibians, laboratory studies testing host susceptibility, and data from prospective studies that test for Bsal ’s presence in a location. We conducted a systematic review of the published literature and compiled a dataset of Bsal tests. We identified 67 species that have been reported positive for Bsal, 20 of which have a threatened conservation status. The distribution of species that have been found with infection encompasses 69 countries, highlighting the potential threat that Bsal poses. We point out where surveillance to detect Bsal have taken place and highlight areas that have not been well monitored. The large number of host species belonging to the families Plethodontidae and Salamandridae suggests a taxonomic pattern of susceptibility. Our results provide insight into the risk posed by Bsal and identifies vulnerable species and areas where surveillance is needed to fill existing knowledge gaps.
... To predict the environmental suitability of Bsal in the United States, we used the MaxEnt algorithm as implemented in the 'dismo' package version 1.1-4 Phillips & Dudík, 2008) in Occurrence points for Bsal in Asia (n = 34) and Europe (n = 19) were taken from González et al. (2019) and Beukema et al. (2018). All of our predictor variables were cropped to the three study extents and resampled to achieve a spatial resolution of 10 kilometres, which was chosen to capture the uncertainty in the location of Bsal occurrence points due to variable location measurement precision. ...
... Furthermore, if there were other species in the same location in the wild as the species that tested positive, and those sympatric species tested negative, we recorded those species as negative, because we assumed they had high likelihood of contact with Bsal (e.g. González et al., 2019) (see Table S1.2 for a list of studies from which infection data were collected). ...
Article
Full-text available
Aim Amphibian populations are threatened globally by anthropogenic change and Batrachochytrium dendrobatidis (Bd), a fungal pathogen causing chytridiomycosis disease to varying degrees of severity. A closely related new fungal pathogen, Batrachochytrium salamandrivorans (Bsal), has recently left its supposed native range in Asia and decimated some salamander populations in Europe. Despite being noticed initially for causing chytridiomycosis‐related population declines in salamanders, Bsal can also infect anurans and cause non‐lethal chytridiomycosis or asymptomatic infections in salamanders. Bsal has not yet been detected in the United States, but given the United States has the highest salamander biodiversity on Earth, predictive assessments of salamander risk to Bsal infection will enable proactive allocation of research and conservation efforts into disease prevention and mitigation. Location The United States, Europe and Asia. Methods We first predicted the environmental suitability for the Bsal pathogen in the United States through an ecological niche model based on the pathogen's known native range in Asia, validated on the observed invasive range in Europe using bioclimatic, land cover, elevation, soil characteristics and human modification variables. Second, we predicted the susceptibility of salamander species to Bsal infection using a machine‐learning model that correlated life history traits with published data on confirmed species infections. Finally, we mapped the geographic ranges of the subset of species that were predicted to be susceptible to Bsal infection. Results In the United States, the overlap of environmental suitability and susceptible salamander species was greatest in the Pacific Northwest, near the Gulf of Mexico, and along the Atlantic coast, and in inland states east of the Plains region. Main Conclusions The overlap of these metrics identify salamander populations that may be at risk of developing Bsal infection and suggests priorities for pre‐emptive research and conservation measures to protect at‐risk salamander species from an additional pathogenic threat.
... Since the description of Bsal, monitoring efforts have been focused on Europe where massive screenings were carried out [3,10]. Nevertheless, Asia has been subject to substantially less Bsal sampling, excluding Vietnam [6], China [11] and Taiwan [12]. ...
Article
Full-text available
The chytrid fungus Batrachochytrium salamandrivorans [Bsal] is causing declines in the amphibian populations. After a decade of mapping the pathogen in Europe, where it is causing dramatic outbreaks, and North America, where its arrival would affect to the salamander’s biodiversity hotspot, little is known about its current status in Asia, from presumably is native. Japan has several species considered as potential carriers, but no regulation is implemented against Bsal spreading. Previous Bsal known presence detected various cases on the Okinawa Island, southwestern Japan. Previous studies on its sister species, B. dendrobatidis presented a high genomic variation in this area and particularly on Cynops ensicauda. Here, we have done the largest monitoring to date in Japan on the Cynops genus, focusing on Okinawa Island and updating its distribution and providing more information to unravel the still unknown origin of Bsal. Interestingly, we have provided revealing facts about different detectability depending on the used molecular techniques and changes in its Japanese distribution. All in all, the Bsal presence in Japan, together with its low variability in the sequenced amplicons, and the lack of apparent mortalities, may indicate that this part of Asia has a high diversity of chytrids.
... This role increases Bsal dispersal pathways as well as disease risk to sensitive salamander species and populations as some of these species tend co-occur with anurans in the same habitat. Therefore, identifying reservoir hosts is crucial for understanding infection dynamics and potential occurrences as Bsal continues to expand its range and threaten biodiversity [23][24][25]. ...
Article
Full-text available
The chytrid fungal pathogens Batrachochytrium salamandrivorans (Bsal) and B. dendrobatidis (Bd) are driving amphibian extinctions and population declines worldwide. As their origins are believed to be in East/Southeast Asia, this region is crucial for understanding their ecology. However, Bsal screening is relatively limited in this region, particularly in hotspots where Bd lineage diversity is high. To address this gap, we conducted an extensive Bsal screening involving 1101 individuals from 36 amphibian species, spanning 17 natural locations and four captive facilities in the biodiversity-rich Guangxi Zhuang Autonomous Region (GAR). Our PCR assays yielded unexpected results, revealing the complete absence of Bsal in all tested samples including 51 individuals with Bd presence. To understand the potential distribution of Bsal, we created niche models, utilizing existing occurrence records from both Asia and Europe. These models estimated potential suitable habitats for Bsal largely in the northern and southwestern parts of the GAR. Although Bsal was absent in our samples, the niche models identified 10 study sites as being potentially suitable for this pathogen. Interestingly, out of these 10 sites, Bd was detected at 8. This suggests that Bsal and Bd could possibly co-exist in these habitats, if Bsal were present. Several factors seem to influence the distribution of Bsal in Asia, including variations in temperature, local caudate species diversity, elevation, and human population density. However, it is climate-related factors that hold the greatest significance, accounting for a notable 60% contribution. The models propose that the specific climatic conditions of arid regions, primarily seen in the GAR, play a major role in the distribution of Bsal. Considering the increased pathogenicity of Bsal at stable and cooler temperatures (10–15 °C), species-dependent variations, and the potential for seasonal Bd-Bsal interactions, we emphasize the importance of periodic monitoring for Bsal within its projected range in the GAR. Our study provides deeper insights into Bsal’s ecological niche and the knowledge generated will facilitate conservation efforts in amphibian populations devastated by chytrid pathogens across other regions of the world.
... This disease has already led to the decline or extinction of several hundred species and continues to cause mass mortality events on five continents (Scheele et al. 2019). Because Bsal has only been discovered recently (Martel et al. 2013) and its distribution range is confined to date to the northwest of continental Europe (Spitzen-van der Sluijs et al. 2016;González et al. 2019), here we concentrate on the better known and globally distributed Bd. The fungus infects keratinous epidermal layers of the skin (Berger et al. 1998). ...
Article
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Chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), has caused extreme losses in amphibian biodiversity. Finding bacteria that produce metabolites with antifungal properties may turn out to be invaluable in the fight against this devastating disease. The entomopathogenic bacteria, Xenorhabdus szentirmaii and X. budapestensis produce secondary metabolites that are effective against a wide range of fungal plant pathogens. To assess whether they may also be effective against Bd, we extracted cell-free culture media (CFCM) from liquid cultures of X. szentirmaii and X. budapestensis and tested their ability to inhibit Bd growth in vitro. As a second step, using juvenile common toads (Bufo bufo) experimentally infected with Bd we also tested the in vivo antifungal efficacy of X. szentirmaii CFCM diluted to 2 and 10% (v/v), while also assessing possible malign side effects on amphibians. Results of the in vitro experiment documented highly effective growth inhibition by CFCMs of both Xenorhabdus species. The in vivo experiment showed that treatment with CFCM of X. szentirmaii applied at a dilution of 10% resulted in infection intensities reduced by ca. 73% compared to controls and to juvenile toads treated with CFCM applied at a dilution of 2%. At the same time, we detected no negative side effects of treatment with CFCM on toad survival and development. Our results clearly support the idea that metabolites of X. szentirmaii, and perhaps of several other Xenorhabdus species as well, may prove highly useful for the treatment of Bd infected amphibians.
... Mycotic diseases affect multiple taxa including plants, mammals, fish, corals, and amphibians, among others (Sutherland et al., 2014). For instance, Pseudogymnoascus destructans causes white-nose syndrome (WNS) in bats Gargas et al., 2009), Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal) cause chytridiomycosis in frogs, salamanders, newts, and caecilians Chandler et al., 2019;Lastra Gonzalez et al., 2019), Aspergillus sydowii has been associated with disease in soft corals (Fisher et al., 2012), and Nosema spp. affect bees (Fisher et al., 2012). ...
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... In contrast, we did not find any individuals infected with the emerging amphibian pathogen Bsal. This is in line with a previous screening for Bsal, which did not detect the pathogen in any of approximately 300 studied salamanders from Poland (Lastra González et al. 2019). The ubiquity of Bd (and to a lesser extent Rv) suggests that recent amphibian declines in this region (Pabijan & Ogielska 2019) may not only be due to widespread habitat conversion, but may be partially attributable to previous or ongoing disease outbreaks that have gone unrecognized. ...
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