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Lastra González D, Nishikawa K, Eto K, Terui S, Kamimura R, Viñuela Rodríguez N, Yoshikawa N, Tominaga A. Lack of variations in the salamander chytrid fungus, Batrachochytrium salamandrivorans, at its alleged origin: Updating its Japanese distribution with new evidence. PLoS One 2024; 19:e0305228. [PMID: 38870137 PMCID: PMC11175521 DOI: 10.1371/journal.pone.0305228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 05/27/2024] [Indexed: 06/15/2024] Open
Abstract
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.
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Affiliation(s)
- David Lastra González
- Department of Natural Sciences, Faculty of Education, University of the Ryukyus, Nishihara, Okinawa, Japan
- Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Prague – Suchdol, Czech Republic
| | - Kanto Nishikawa
- Graduate School of Global Environmental Studies, Kyoto University, Yoshida Hon-machi, Sakyo, Japan
| | - Koshiro Eto
- Kitakyushu Museum of Natural History & Human History, Kitakyushu, Fukuoka, Japan
| | - Shigeharu Terui
- Environment Grasp Promotion Network-PEG, Nonprofit Organization, Kushiro-shi, Hokkaido, Japan
| | - Ryo Kamimura
- Graduate school of Engineering and Science, University of the Ryukyus, Nishihara, Okinawa, Japan
| | - Nuria Viñuela Rodríguez
- Molecular Invertebrate Systematics and Ecology [MISE] Lab, Graduate School of Engineering and Science, University of the Ryukyus, Nishihara, Okinawa, Japan
| | - Natsuhiko Yoshikawa
- Department of Zoology, National Museum of Nature and Science, Tokyo, Tsukuba, Ibaraki, Japan
| | - Atsushi Tominaga
- Department of Natural Sciences, Faculty of Education, University of the Ryukyus, Nishihara, Okinawa, Japan
- Graduate school of Engineering and Science, University of the Ryukyus, Nishihara, Okinawa, Japan
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Böning P, Lötters S, Barzaghi B, Bock M, Bok B, Bonato L, Ficetola GF, Glaser F, Griese J, Grabher M, Leroux C, Munimanda G, Manenti R, Ludwig G, Preininger D, Rödel MO, Seibold S, Smith S, Tiemann L, Thein J, Veith M, Plewnia A. Alpine salamanders at risk? The current status of an emerging fungal pathogen. PLoS One 2024; 19:e0298591. [PMID: 38758948 PMCID: PMC11101120 DOI: 10.1371/journal.pone.0298591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 01/28/2024] [Indexed: 05/19/2024] Open
Abstract
Amphibians globally suffer from emerging infectious diseases like chytridiomycosis caused by the continuously spreading chytrid fungi. One is Batrachochytrium salamandrivorans (Bsal) and its disease ‒ the 'salamander plague' ‒ which is lethal to several caudate taxa. Recently introduced into Western Europe, long distance dispersal of Bsal, likely through human mediation, has been reported. Herein we study if Alpine salamanders (Salamandra atra and S. lanzai) are yet affected by the salamander plague in the wild. Members of the genus Salamandra are highly susceptible to Bsal leading to the lethal disease. Moreover, ecological modelling has shown that the Alps and Dinarides, where Alpine salamanders occur, are generally suitable for Bsal. We analysed skin swabs of 818 individuals of Alpine salamanders and syntopic amphibians at 40 sites between 2017 to 2022. Further, we compiled those with published data from 319 individuals from 13 sites concluding that Bsal infections were not detected. Our results suggest that the salamander plague so far is absent from the geographic ranges of Alpine salamanders. That means that there is still a chance to timely implement surveillance strategies. Among others, we recommend prevention measures, citizen science approaches, and ex situ conservation breeding of endemic salamandrid lineages.
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Affiliation(s)
- Philipp Böning
- Department of Biogeography, Trier University, Trier, Germany
| | - Stefan Lötters
- Department of Biogeography, Trier University, Trier, Germany
| | - Benedetta Barzaghi
- Department of Environmental Science and Policy, University of Milan, Milan, Italy
| | - Marvin Bock
- Department of Biogeography, Trier University, Trier, Germany
| | - Bobby Bok
- St. Michael College, Zaandam, Netherlands
| | - Lucio Bonato
- Department of Biology, University of Padova, Padova, Italy
- National Biodiversity Future Center, Palermo, Italy
| | | | | | | | | | - Camille Leroux
- Centre d’Ecologie et des Sciences de la Conservation (CESCO), Muséum National d’Histoire Naturelle, Centre National de la Recherche Scientifique, Sorbonne Université, Paris, France
- Auddicé Biodiversité–ZAC du Chevalement, Roost-Warendin, France
- Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
| | - Gopikrishna Munimanda
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Raoul Manenti
- Department of Environmental Science and Policy, University of Milan, Milan, Italy
| | | | | | - Mark-Oliver Rödel
- Museum für Naturkunde–Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
| | - Sebastian Seibold
- Forest Zoology, Technische Universität Dresden, Tharandt, Germany
- Berchtesgaden National Park, Berchtesgaden, Germany
- Ecosystem Dynamics and Forest Management, Technical University of Munich, Freising, Germany
| | - Steve Smith
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Laura Tiemann
- Department of Neurology, TUM School of Medicine, Technical University of Munich, Munich, Germany
| | - Jürgen Thein
- Büro für Faunistik und Umweltbildung, Haßfurt, Germany
| | - Michael Veith
- Department of Biogeography, Trier University, Trier, Germany
| | - Amadeus Plewnia
- Department of Biogeography, Trier University, Trier, Germany
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Chen G, Lau A, Wan B, Poon ESK, Fung HS, Lee WH, Sung YH, Sin SYW. OCCURRENCE OF PATHOGENIC CHYTRID FUNGI BATRACHOCHYTRIUM SALAMANDRIVORANS AND BATRACHOCHYTRIUM DENDROBATIDIS IN THE HONG KONG NEWT (PARAMESOTRITON HONGKONGENSIS) AND OTHER WILD AND IMPORTED AMPHIBIANS IN A SUBTROPICAL ASIAN REGION. J Wildl Dis 2023; 59:709-721. [PMID: 37768785 DOI: 10.7589/jwd-d-22-00145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 05/26/2023] [Indexed: 09/30/2023]
Abstract
One of the major threats for the massive loss in global amphibian diversity is chytridiomycosis, caused by chytrid fungi Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal). Following its discovery in 2013, Bsal has emerged as a severe threat to the global survival of urodelans. In 2018, a study reported a high prevalence of Bsal (65.6%) in the Hong Kong newts (Paramesotriton hongkongensis, Near Threatened) of a southern China population adjacent to Hong Kong (HK). Uncertainty regarding the Bsal infection status of P. hongkongensis inhabiting HK raised deep concern over the risk of introducing Bsal from that population. We screened the skin swabs from wild individuals of P. hongkongensis, 15 sympatric amphibian species, and 16 imported amphibian species in HK for chytrids. We found that both Bsal and Bd occur in low prevalences in P. hongkongensis (Bsal 1.7%, 5/293; Bd 0.34%, 1/293), Hong Kong cascade frog, Amolops hongkongensis, family Ranidae (Bsal only, 5.26%, 1/19), and Asian common toad, Duttaphrynus melanostictus, family Bufonidae (Bsal only, 5.88%, 1/17), populations of HK, with infected individuals being asymptomatic, suggesting a potential role of these species as reservoirs of Bsal. Conversely, Bd, but not Bsal, was present on 13.2% (9/68) of imported amphibians, indicating a high chytrid introduction risk posed by international amphibian trade. Long-term surveillance of the presence of Bd and Bsal in wild and captive amphibians would be advisable, and we recommend that import and export of nonnative chytrid carriers should be prevented, especially to those regions with amphibian populations naïve to Bd and Bsal.
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Affiliation(s)
- Guoling Chen
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam Road, Hong Kong, China
| | - Anthony Lau
- Science Unit, Lingnan University, Tuen Mun, Hong Kong, China
| | - Bowen Wan
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam Road, Hong Kong, China
| | - Emily Shui Kei Poon
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam Road, Hong Kong, China
| | - Hon Shing Fung
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam Road, Hong Kong, China
| | - Wing Ho Lee
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam Road, Hong Kong, China
| | - Yik-Hei Sung
- Science Unit, Lingnan University, Tuen Mun, Hong Kong, China
| | - Simon Yung Wa Sin
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam Road, Hong Kong, China
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Erens J, Preissler K, Speybroeck J, Beukema W, Spitzen-van der Sluijs A, Stark T, Laudelout A, Kinet T, Schmidt BR, Martel A, Steinfartz S, Pasmans F. Divergent population responses following salamander mass mortalities and declines driven by the emerging pathogen Batrachochytrium salamandrivorans. Proc Biol Sci 2023; 290:20230510. [PMID: 37752840 PMCID: PMC10523083 DOI: 10.1098/rspb.2023.0510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 08/31/2023] [Indexed: 09/28/2023] Open
Abstract
Understanding wildlife responses to novel threats is vital in counteracting biodiversity loss. The emerging pathogen Batrachochytrium salamandrivorans (Bsal) causes dramatic declines in European salamander populations, and is considered an imminent threat to global amphibian biodiversity. However, real-life disease outcomes remain largely uncharacterized. We performed a multidisciplinary assessment of the longer-term impacts of Bsal on highly susceptible fire salamander (Salamandra salamandra) populations, by comparing four of the earliest known outbreak sites to uninfected sites. Based on large-scale monitoring efforts, we found population persistence in strongly reduced abundances to over a decade after Bsal invasion, but also the extinction of an initially small-sized population. In turn, we found that host responses varied, and Bsal detection remained low, within surviving populations. Demographic analyses indicated an ongoing scarcity of large reproductive adults with potential for recruitment failure, while spatial comparisons indicated a population remnant persisting within aberrant habitat. Additionally, we detected no early signs of severe genetic deterioration, yet nor of increased host resistance. Beyond offering additional context to Bsal-driven salamander declines, results highlight how the impacts of emerging hypervirulent pathogens can be unpredictable and vary across different levels of biological complexity, and how limited pathogen detectability after population declines may complicate surveillance efforts.
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Affiliation(s)
- Jesse Erens
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | | | | | - Wouter Beukema
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
- Reptile, Amphibian & Fish Conservation Netherlands (RAVON), Nijmegen, the Netherlands
| | - Annemarieke Spitzen-van der Sluijs
- Reptile, Amphibian & Fish Conservation Netherlands (RAVON), Nijmegen, the Netherlands
- Institute for Water and Wetland Research, Animal Ecology and Physiology, Radboud University, Nijmegen, the Netherlands
| | - Tariq Stark
- Reptile, Amphibian & Fish Conservation Netherlands (RAVON), Nijmegen, the Netherlands
| | | | | | - Benedikt R. Schmidt
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Info fauna karch, Neuchâtel, Switzerland
| | - An Martel
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | | | - Frank Pasmans
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
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Sun D, Ellepola G, Herath J, Meegaskumbura M. Ecological Barriers for an Amphibian Pathogen: A Narrow Ecological Niche for Batrachochytrium salamandrivorans in an Asian Chytrid Hotspot. J Fungi (Basel) 2023; 9:911. [PMID: 37755019 PMCID: PMC10532633 DOI: 10.3390/jof9090911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/02/2023] [Accepted: 09/05/2023] [Indexed: 09/28/2023] Open
Abstract
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.
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Affiliation(s)
- Dan Sun
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530000, China; (D.S.)
| | - Gajaba Ellepola
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530000, China; (D.S.)
- Department of Zoology, Faculty of Science, University of Peradeniya, Peradeniya, Kandy 20400, Sri Lanka
| | - Jayampathi Herath
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530000, China; (D.S.)
- School of Biomedical Sciences, International Institute of Health Sciences (IIHS), No. 704 Negombo Road, Welisara 71722, Sri Lanka
| | - Madhava Meegaskumbura
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530000, China; (D.S.)
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Ujszegi J, Boros Z, Fodor A, Vajna B, Hettyey A. Metabolites of Xenorhabdus bacteria are potent candidates for mitigating amphibian chytridiomycosis. AMB Express 2023; 13:88. [PMID: 37615904 PMCID: PMC10449739 DOI: 10.1186/s13568-023-01585-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 07/20/2023] [Indexed: 08/25/2023] Open
Abstract
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.
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Affiliation(s)
- János Ujszegi
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Budapest, Hungary.
- Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary.
| | - Zsófia Boros
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Budapest, Hungary
- Department of Genetics, Eötvös Loránd University, Budapest, Hungary
- Department of Microbiology, Eötvös Loránd University, Budapest, Hungary
| | - András Fodor
- Department of Genetics, Eötvös Loránd University, Budapest, Hungary
| | - Balázs Vajna
- Department of Microbiology, Eötvös Loránd University, Budapest, Hungary
| | - Attila Hettyey
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Budapest, Hungary
- Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary
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Sun D, Ellepola G, Herath J, Meegaskumbura M. The two chytrid pathogens of amphibians in Eurasia-climatic niches and future expansion. BMC Ecol Evol 2023; 23:26. [PMID: 37370002 DOI: 10.1186/s12862-023-02132-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 06/12/2023] [Indexed: 06/29/2023] Open
Abstract
BACKGROUND Climate affects the thermal adaptation and distribution of hosts, and drives the spread of Chytridiomycosis-a keratin-associated infectious disease of amphibians caused by the sister pathogens Batrachochytrium dendrobatidi (Bd) and B. salamandrivorans (Bsal). We focus on their climate-pathogen relationships in Eurasia, the only region where their geographical distributions overlap. Eurasia harbours invaded and native areas of both pathogens and the natural habitats where they co-exist, making it an ideal region to examine their environmental niche correlations. Our understanding of how climate change will affect their distribution is broadened by the differences in climate correlates and niche characteristics between Bd and Bsal in Asia and Europe. This knowledge has potential conservation implications, informing future spread of the disease in different regions. RESULTS We quantified the environmental niche overlap between Bd and Bsal in Eurasia using niche analyses. Results revealed partial overlap in the niche with a unique 4% of non-overlapping values for Bsal, suggesting segregation along certain climate axes. Bd tolerates higher temperature fluctuations, while Bsal requires more stable, lower temperature and wetter conditions. Projections of their Realized Climatic Niches (RCNs) to future conditions show a larger expansion of suitable ranges (SRs) for Bd compared to Bsal in both Asia and Europe, with their centroids shifting in different directions. Notably, both pathogens' highly suitable areas in Asia are expected to shrink significantly, especially under the extreme climate scenarios. In Europe, they are expected to expand significantly. CONCLUSIONS Climate change will impact or increase disease risk to amphibian hosts, particularly in Europe. Given the shared niche space of the two pathogens across available climate gradients, as has already been witnessed in Eurasia with an increased range expansion and niche overlap due to climate change, we expect that regions where Bsal is currently absent but salamanders are present, and where Bd is already prevalent, may be conducive for the spread of Bsal.
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Affiliation(s)
- Dan Sun
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, 530000, People's Republic of China
| | - Gajaba Ellepola
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, 530000, People's Republic of China
- Department of Zoology, Faculty of Science, University of Peradeniya, Peradeniya, Kandy, 20400, Sri Lanka
| | - Jayampathi Herath
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, 530000, People's Republic of China
| | - Madhava Meegaskumbura
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, 530000, People's Republic of China.
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Gray MJ, Carter ED, Piovia-Scott J, Cusaac JPW, Peterson AC, Whetstone RD, Hertz A, Muniz-Torres AY, Bletz MC, Woodhams DC, Romansic JM, Sutton WB, Sheley W, Pessier A, McCusker CD, Wilber MQ, Miller DL. Broad host susceptibility of North American amphibian species to Batrachochytrium salamandrivorans suggests high invasion potential and biodiversity risk. Nat Commun 2023; 14:3270. [PMID: 37277333 DOI: 10.1038/s41467-023-38979-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 05/22/2023] [Indexed: 06/07/2023] Open
Abstract
Batrachochytrium salamandrivorans (Bsal) is a fungal pathogen of amphibians that is emerging in Europe and could be introduced to North America through international trade or other pathways. To evaluate the risk of Bsal invasion to amphibian biodiversity, we performed dose-response experiments on 35 North American species from 10 families, including larvae from five species. We discovered that Bsal caused infection in 74% and mortality in 35% of species tested. Both salamanders and frogs became infected and developed Bsal chytridiomycosis. Based on our host susceptibility results, environmental suitability conditions for Bsal, and geographic ranges of salamanders in the United States, predicted biodiversity loss is expected to be greatest in the Appalachian Region and along the West Coast. Indices of infection and disease susceptibility suggest that North American amphibian species span a spectrum of vulnerability to Bsal chytridiomycosis and most amphibian communities will include an assemblage of resistant, carrier, and amplification species. Predicted salamander losses could exceed 80 species in the United States and 140 species in North America.
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Affiliation(s)
- Matthew J Gray
- Center for Wildlife Health, School of Natural Resources, University of Tennessee, Knoxville, TN, USA.
| | - Edward Davis Carter
- Center for Wildlife Health, School of Natural Resources, University of Tennessee, Knoxville, TN, USA
| | - Jonah Piovia-Scott
- School of Biological Sciences, Washington State University, Vancouver, WA, USA
| | - J Patrick W Cusaac
- Center for Wildlife Health, School of Natural Resources, University of Tennessee, Knoxville, TN, USA
| | - Anna C Peterson
- Center for Wildlife Health, School of Natural Resources, University of Tennessee, Knoxville, TN, USA
| | - Ross D Whetstone
- Biology Department, University of Massachusetts Boston, Boston, MA, USA
| | - Andreas Hertz
- Biology Department, University of Massachusetts Boston, Boston, MA, USA
| | | | - Molly C Bletz
- Biology Department, University of Massachusetts Boston, Boston, MA, USA
| | - Douglas C Woodhams
- Biology Department, University of Massachusetts Boston, Boston, MA, USA
- Smithsonian Tropical Research Institute, Ancón, Panama
| | - John M Romansic
- School of Biological Sciences, Washington State University, Vancouver, WA, USA
| | - William B Sutton
- Department of Agricultural and Environmental Sciences, Tennessee State University, Nashville, TN, USA
| | - Wesley Sheley
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Knoxville, TN, USA
| | - Allan Pessier
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | | | - Mark Q Wilber
- Center for Wildlife Health, School of Natural Resources, University of Tennessee, Knoxville, TN, USA
| | - Debra L Miller
- Center for Wildlife Health, School of Natural Resources, University of Tennessee, Knoxville, TN, USA
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Knoxville, TN, USA
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9
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Schilliger L, Paillusseau C, François C, Bonwitt J. Major Emerging Fungal Diseases of Reptiles and Amphibians. Pathogens 2023; 12:pathogens12030429. [PMID: 36986351 PMCID: PMC10053826 DOI: 10.3390/pathogens12030429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/16/2023] [Accepted: 03/06/2023] [Indexed: 03/11/2023] Open
Abstract
Emerging infectious diseases (EIDs) are caused by pathogens that have undergone recent changes in terms of geographic spread, increasing incidence, or expanding host range. In this narrative review, we describe three important fungal EIDs with keratin trophism that are relevant to reptile and amphibian conservation and veterinary practice. Nannizziopsis spp. have been mainly described in saurians; infection results in thickened, discolored skin crusting, with eventual progression to deep tissues. Previously only reported in captive populations, it was first described in wild animals in Australia in 2020. Ophidiomyces ophidiicola (formely O. ophiodiicola) is only known to infect snakes; clinical signs include ulcerating lesions in the cranial, ventral, and pericloacal regions. It has been associated with mortality events in wild populations in North America. Batrachochytrium spp. cause ulceration, hyperkeratosis, and erythema in amphibians. They are a major cause of catastrophic amphibian declines worldwide. In general, infection and clinical course are determined by host-related characteristics (e.g., nutritional, metabolic, and immune status), pathogens (e.g., virulence and environmental survival), and environment (e.g., temperature, hygrometry, and water quality). The animal trade is thought to be an important cause of worldwide spread, with global modifications in temperature, hygrometry, and water quality further affecting fungal pathogenicity and host immune response.
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Affiliation(s)
- Lionel Schilliger
- Argos Veterinary Clinic of Paris Auteuil, 35 Rue Leconte de Lisle, 75016 Paris, France
- SpéNac Referral Center, 100 Boulevard de la Tour Maubourg, 75007 Paris, France
- Correspondence: ; Tel.: +33-188-616-831
| | - Clément Paillusseau
- Argos Veterinary Clinic of Paris Auteuil, 35 Rue Leconte de Lisle, 75016 Paris, France
- SpéNac Referral Center, 100 Boulevard de la Tour Maubourg, 75007 Paris, France
| | - Camille François
- Argos Veterinary Clinic of Paris Auteuil, 35 Rue Leconte de Lisle, 75016 Paris, France
- SpéNac Referral Center, 100 Boulevard de la Tour Maubourg, 75007 Paris, France
| | - Jesse Bonwitt
- Department of Anthropology, Durham University, South Rd., Durham DH1 3LE, UK
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10
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Strachinis I, Marschang RE, Lymberakis P, Karagianni KM, Azmanis P. Infectious disease threats to amphibians in Greece: new localities positive for Batrachochytrium dendrobatidis. DISEASES OF AQUATIC ORGANISMS 2022; 152:127-138. [PMID: 36519684 DOI: 10.3354/dao03712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
In the early 2000s, numerous cases of European amphibian population declines and mass die-offs started to emerge. Investigating those events led to the discovery that wild European amphibians were confronted with grave disease threats caused by introduced pathogens, namely the amphibian and the salamander chytrid fungi Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal) and ranaviruses. In Greece, Bd was previously documented among wild amphibian populations in 2 different locations and 3 different species. However, no disease-related mass declines or mortality events have been reported. In this work, we build upon previous findings with new, subsequently obtained data, resulting in a 225-sample dataset of 14 species from 17 different locations throughout Greece, in order to examine the occurrence status of all 3 pathogens responsible for emerging infectious diseases in European amphibians. No positive samples for Bsal or ranavirus were recorded in any location. We confirmed the presence of Bd in 4 more localities and in 4 more species, including 1 urodelan (Macedonian crested newt Triturus macedonicus) and 1 introduced anuran (American bullfrog Lithobates catesbeianus). All insular localities were negative for Bd, except for Crete, where Bd was identified in 2 different locations. Again, no mass declines or die-offs were recorded in any Bd-positive area or elsewhere. However, given the persistence of Bd across Greece over the past ~20 yr, monitoring efforts should continue, and ideally be further expanded.
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Affiliation(s)
- Ilias Strachinis
- Department of Genetics, Development and Molecular Biology, School of Biology, Faculty of Natural Sciences, Aristotle University of Thessaloniki, 54636, Greece
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11
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Castro Monzon F, Rödel MO, Ruland F, Parra-Olea G, Jeschke JM. Batrachochytrium salamandrivorans' Amphibian Host Species and Invasion Range. ECOHEALTH 2022; 19:475-486. [PMID: 36611108 PMCID: PMC9898388 DOI: 10.1007/s10393-022-01620-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 08/31/2022] [Indexed: 06/17/2023]
Abstract
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.
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Affiliation(s)
- Federico Castro Monzon
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Str. 1-3, 14195, Berlin, Germany.
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587, Berlin, Germany.
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, Altensteinstr. 34, 14195, Berlin, Germany.
- Department of Zoology, Institute of Biology, Universidad Nacional Autonoma de Mexico, AP 70-153, 04510, Mexico City, Mexico.
| | - Mark-Oliver Rödel
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, Altensteinstr. 34, 14195, Berlin, Germany
- Museum für Naturkunde-Leibniz Institute for Evolution and Biodiversity Science, Invalidenstr. 43, 10115, Berlin, Germany
| | - Florian Ruland
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Str. 1-3, 14195, Berlin, Germany
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, Altensteinstr. 34, 14195, Berlin, Germany
| | - Gabriela Parra-Olea
- Department of Zoology, Institute of Biology, Universidad Nacional Autonoma de Mexico, AP 70-153, 04510, Mexico City, Mexico
| | - Jonathan M Jeschke
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Str. 1-3, 14195, Berlin, Germany
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, Altensteinstr. 34, 14195, Berlin, Germany
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12
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Womack MC, Steigerwald E, Blackburn DC, Cannatella DC, Catenazzi A, Che J, Koo MS, McGuire JA, Ron SR, Spencer CL, Vredenburg VT, Tarvin RD. State of the Amphibia 2020: A Review of Five Years of Amphibian Research and Existing Resources. ICHTHYOLOGY & HERPETOLOGY 2022. [DOI: 10.1643/h2022005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Molly C. Womack
- Department of Biology, Utah State University, Logan, Utah 84322; . ORCID: 0000-0002-3346-021X
| | - Emma Steigerwald
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California 94720; (ES) ; (MSK) ; (JAM) ; (CS) ; (VTV) ; and (RDT)
| | - David C. Blackburn
- Department of Natural History, Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611; . ORCID: 0000-0002-1810-9886
| | - David C. Cannatella
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas 78712; . ORCID: 0000-0001-8675-0520
| | | | - Jing Che
- State Key Laboratory of Genetic Resources and Evolution & Yunnan Key Laboratory of Biodiversity and Ecological Security of Gaoligong Mountain, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China; . ORCID: 0000-0003-4246-6
| | - Michelle S. Koo
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California 94720; (ES) ; (MSK) ; (JAM) ; (CS) ; (VTV) ; and (RDT)
| | - Jimmy A. McGuire
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California 94720; (ES) ; (MSK) ; (JAM) ; (CS) ; (VTV) ; and (RDT)
| | - Santiago R. Ron
- Museo de Zoología, Escuela de Biología, Pontificia Universidad Católica del Ecuador, Quito, Ecuador; . ORCID: 0000-0001-6300-9350
| | - Carol L. Spencer
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California 94720; (ES) ; (MSK) ; (JAM) ; (CS) ; (VTV) ; and (RDT)
| | - Vance T. Vredenburg
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California 94720; (ES) ; (MSK) ; (JAM) ; (CS) ; (VTV) ; and (RDT)
| | - Rebecca D. Tarvin
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California 94720; (ES) ; (MSK) ; (JAM) ; (CS) ; (VTV) ; and (RDT)
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13
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Voglmayr H, Schertler A, Essl F, Krisai-Greilhuber I. Alien and cryptogenic fungi and oomycetes in Austria: an annotated checklist (2nd edition). Biol Invasions 2022; 25:27-38. [PMID: 36643959 PMCID: PMC9832105 DOI: 10.1007/s10530-022-02896-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 08/08/2022] [Indexed: 01/18/2023]
Abstract
Fungal invasions can have far-reaching consequences, and despite increasing relevance, fungi are notoriously underrepresented in invasion science. Here, we present the second annotated checklist for alien and cryptogenic fungi and oomycetes in Austria. This list contains 375 taxa of which 278 are classified as established; compared to the first checklist from 2002, this amounts to an almost five-fold increase and the number of decade-wise first records is steadily rising since the mid-twentieth century. The introduction pathway is unclear for the vast majority of taxa, while the main means of spread within the country is unassisted secondary spread. Fungi were predominantly introduced from the Northern Hemisphere, especially North America and Temperate Asia. Rates of newly recorded alien fungi differ among phyla; the majority belongs to the Ascomycota, which experienced an 9.6-fold increase in numbers. Orders found most frequently are powdery mildews (Erysiphales, Ascomycota), downy mildews (Peronosporales, Oomycota), agarics (Agaricales, Basidiomycota), Mycosphaerellales (Ascomycota), rusts (Pucciniales, Basidiomycota) and Pleosporales (Ascomycota). The majority (about 80%) of the taxa are plant pathogens, while animal pathogens are few but severely affecting their native hosts. The dominance of pathogens in our checklist underlines the need of better tackling fungal invasions-especially in the light of emerging infectious diseases-and highlights potential knowledge gaps for ectomycorrhizal and saprobic alien fungi, whose invasion processes are often much more inconspicuous. Our results show that fungal invasions are a phenomenon of increasing importance, and collaborative efforts are needed for advancing the knowledge and management of this important group. Supplementary Information The online version contains supplementary material available at 10.1007/s10530-022-02896-2.
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Affiliation(s)
- Hermann Voglmayr
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Anna Schertler
- BioInvasions, Global Change, Macroecology-Group, Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Franz Essl
- BioInvasions, Global Change, Macroecology-Group, Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Irmgard Krisai-Greilhuber
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
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14
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Zalar P, Gubenšek A, Gostincar C, Kostanjšek R, Bizjak-Mali L, Gunde-Cimerman N. Cultivable Skin Mycobiota of Healthy and Diseased Blind Cave Salamander (Proteus anguinus). Front Microbiol 2022; 13:926558. [PMID: 35910647 PMCID: PMC9329069 DOI: 10.3389/fmicb.2022.926558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 06/24/2022] [Indexed: 11/13/2022] Open
Abstract
Proteus anguinus is a neotenic cave salamander, endemic to the Dinaric Karst and a symbol of world natural heritage. It is classified as “vulnerable” by the International Union for Conservation of Nature (IUCN) and is one of the EU priority species in need of strict protection. Due to inaccessibility of their natural underground habitat, scientific studies of the olm have been conducted mainly in captivity, where the amphibians are particularly susceptible to opportunistic microbial infections. In this report, we focused on the diversity of cultivable commensal fungi isolated from the skin of asymptomatic and symptomatic animals obtained from nature (20 specimens) and captivity (22 specimens), as well as from underground water of two karstic caves by direct water filtration and by exposure of keratin-based microbial baits and subsequent isolation from them. In total 244 fungal isolates were recovered from the animals and additional 153 isolates were obtained from water samples. Together, these isolates represented 87 genera and 166 species. Symptomatic animals were colonized by a variety of fungal species, most of them represented by a single isolate, including genera known for their involvement in chromomycosis, phaeohyphomycosis and zygomycosis in amphibians: Acremonium, Aspergillus, Cladosporium, Exophiala, Fusarium, Mucor, Ochroconis, Phialophora and Penicillium. One symptomatic specimen sampled from nature was infected by the oomycete Saprolegnia parasitica, the known causative agent of saprolegniosis. This is the first comprehensive report on cultivable skin mycobiome of this unique amphibian in nature and in captivity, with an emphasis on potentially pathogenic fungi and oomycetes.
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Affiliation(s)
- Polona Zalar
- Chair of Molecular Genetics and Biology of Microorganisms, Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Ana Gubenšek
- Chair of Molecular Genetics and Biology of Microorganisms, Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Cene Gostincar
- Chair of Molecular Genetics and Biology of Microorganisms, Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Rok Kostanjšek
- Chair of Zoology, Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Lilijana Bizjak-Mali
- Chair of Zoology, Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Nina Gunde-Cimerman
- Chair of Molecular Genetics and Biology of Microorganisms, Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
- *Correspondence: Nina Gunde-Cimerman,
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15
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Kásler A, Ujszegi J, Holly D, Üveges B, Móricz ÁM, Herczeg D, Hettyey A. Metamorphic common toads keep chytrid infection under control, but at a cost. J Zool (1987) 2022. [DOI: 10.1111/jzo.12974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. Kásler
- Lendület Evolutionary Ecology Research Group Centre for Agricultural Research Plant Protection Institute Eötvös Loránd Research Network Budapest Hungary
- Doctoral School of Biology Institute of Biology ELTE Eötvös Loránd University Budapest Hungary
| | - J. Ujszegi
- Lendület Evolutionary Ecology Research Group Centre for Agricultural Research Plant Protection Institute Eötvös Loránd Research Network Budapest Hungary
- Department of Systematic Zoology and Ecology Institute of Biology ELTE Eötvös Loránd University Budapest Hungary
| | - D. Holly
- Lendület Evolutionary Ecology Research Group Centre for Agricultural Research Plant Protection Institute Eötvös Loránd Research Network Budapest Hungary
- Doctoral School of Biology Institute of Biology ELTE Eötvös Loránd University Budapest Hungary
| | - B. Üveges
- Lendület Evolutionary Ecology Research Group Centre for Agricultural Research Plant Protection Institute Eötvös Loránd Research Network Budapest Hungary
- Molecular Ecology and Evolution at Bangor School of Natural Sciences Bangor University Bangor UK
| | - Á. M. Móricz
- Department of Pathophysiology Centre for Agricultural Research Plant Protection Institute Eötvös Loránd Research Network Budapest Hungary
| | - D. Herczeg
- Lendület Evolutionary Ecology Research Group Centre for Agricultural Research Plant Protection Institute Eötvös Loránd Research Network Budapest Hungary
| | - A. Hettyey
- Lendület Evolutionary Ecology Research Group Centre for Agricultural Research Plant Protection Institute Eötvös Loránd Research Network Budapest Hungary
- Department of Systematic Zoology and Ecology Institute of Biology ELTE Eötvös Loránd University Budapest Hungary
- Department of Ecology University of Veterinary Medicine Budapest Hungary
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16
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Crawshaw L, Buchanan T, Shirose L, Palahnuk A, Cai HY, Bennett AM, Jardine CM, Davy CM. Widespread occurrence of
Batrachochytrium dendrobatidis
in Ontario, Canada, and predicted habitat suitability for the emerging
Batrachochytrium salamandrivorans. Ecol Evol 2022; 12:e8798. [PMID: 35475183 PMCID: PMC9020443 DOI: 10.1002/ece3.8798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 03/06/2022] [Accepted: 03/16/2022] [Indexed: 12/30/2022] Open
Abstract
Chytridiomycosis, caused by the fungi Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans, is associated with massive amphibian mortality events worldwide and with some species’ extinctions. Previous ecological niche models suggest that B. dendrobatidis is not well‐suited to northern, temperate climates, but these predictions have often relied on datasets in which northern latitudes are underrepresented. Recent northern detections of B. dendrobatidis suggest that these models may have underestimated the suitability of higher latitudes for this fungus. We used qPCR to test for B. dendrobatidis in 1,041 non‐invasive epithelial swab samples from 18 species of amphibians collected across 735,345 km2 in Ontario and Akimiski Island (Nunavut), Canada. We detected the pathogen in 113 samples (10.9%) from 11 species. Only one specimen exhibited potential clinical signs of disease. We used these data to produce six Species Distribution Models of B. dendrobatidis, which classified half of the study area as potential habitat for the fungus. We also tested each sample for B. salamandrivorans, an emerging pathogen that is causing alarming declines in European salamanders, but is not yet detected in North America. We did not detect B. salamandrivorans in any of the samples, providing a baseline for future surveillance. We assessed the potential risk of future introduction by comparing salamander richness to temperature‐dependent mortality, predicted by a previous exposure study. Areas with the highest species diversity and predicted mortality risk extended 60,530 km2 across southern Ontario, highlighting the potential threat B. salamandrivorans poses to northern Nearctic amphibians. Preventing initial introduction will require coordinated, transboundary regulation of trade in amphibians (including frogs that can carry and disperse B. salamandrivorans), and surveillance of the pathways of introduction (e.g., water and wildlife). Our results can inform surveillance for both pathogens and efforts to mitigate the spread of chytridiomycosis through wild populations.
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Affiliation(s)
- Lauren Crawshaw
- Ontario Ministry of Northern Development, Mines, Natural Resources and Forestry Wildlife Research and Monitoring Section Trent University Peterborough ON Canada
| | - Tore Buchanan
- Ontario Ministry of Northern Development, Mines, Natural Resources and Forestry Wildlife Research and Monitoring Section Trent University Peterborough ON Canada
| | - Leonard Shirose
- Canadian Wildlife Health Cooperative Department of Pathobiology University of Guelph Guelph ON Canada
- Department of Pathobiology University of Guelph Guelph ON Canada
| | - Amanda Palahnuk
- Ontario Ministry of Northern Development, Mines, Natural Resources and Forestry Wildlife Research and Monitoring Section Trent University Peterborough ON Canada
| | - Hugh Y. Cai
- Animal Health Laboratory University of Guelph Guelph ON Canada
| | | | - Claire M. Jardine
- Canadian Wildlife Health Cooperative Department of Pathobiology University of Guelph Guelph ON Canada
- Department of Pathobiology University of Guelph Guelph ON Canada
| | - Christina M. Davy
- Ontario Ministry of Northern Development, Mines, Natural Resources and Forestry Wildlife Research and Monitoring Section Trent University Peterborough ON Canada
- Department of Biology Trent University Peterborough ON Canada
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17
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Cowgill M, Zink AG, Sparagon W, Yap TA, Sulaeman H, Koo MS, Vredenburg VT. Social Behavior, Community Composition, Pathogen Strain, and Host Symbionts Influence Fungal Disease Dynamics in Salamanders. Front Vet Sci 2021; 8:742288. [PMID: 34938792 PMCID: PMC8687744 DOI: 10.3389/fvets.2021.742288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 10/06/2021] [Indexed: 11/29/2022] Open
Abstract
The emerging fungal pathogen, Batrachochytrium dendrobatidis (Bd), which can cause a fatal disease called chytridiomycosis, is implicated in the collapse of hundreds of host amphibian species. We describe chytridiomycosis dynamics in two co-occurring terrestrial salamander species, the Santa Lucia Mountains slender salamander, Batrachoseps luciae, and the arboreal salamander, Aneides lugubris. We (1) conduct a retrospective Bd-infection survey of specimens collected over the last century, (2) estimate present-day Bd infections in wild populations, (3) use generalized linear models (GLM) to identify biotic and abiotic correlates of infection risk, (4) investigate susceptibility of hosts exposed to Bd in laboratory trials, and (5) examine the ability of host skin bacteria to inhibit Bd in culture. Our historical survey of 2,866 specimens revealed that for most of the early 20th century (~1920–1969), Bd was not detected in either species. By the 1990s the proportion of infected specimens was 29 and 17% (B. luciae and A. lugubris, respectively), and in the 2010s it was 10 and 17%. This was similar to the number of infected samples from contemporary populations (2014–2015) at 10 and 18%. We found that both hosts experience signs of chytridiomycosis and suffered high Bd-caused mortality (88 and 71% for B. luciae and A. lugubris, respectively). Our GLM revealed that Bd-infection probability was positively correlated with intraspecific group size and proximity to heterospecifics but not to abiotic factors such as precipitation, minimum temperature, maximum temperature, mean temperature, and elevation, or to the size of the hosts. Finally, we found that both host species contain symbiotic skin-bacteria that inhibit growth of Bd in laboratory trials. Our results provide new evidence consistent with other studies showing a relatively recent Bd invasion of amphibian host populations in western North America and suggest that the spread of the pathogen may be enabled both through conspecific and heterospecific host interactions. Our results suggest that wildlife disease studies should assess host-pathogen dynamics that consider the interactions and effects of multiple hosts, as well as the historical context of pathogen invasion, establishment, and epizootic to enzootic transitions to better understand and predict disease dynamics.
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Affiliation(s)
- Mae Cowgill
- Department of Biology, San Francisco State University, San Francisco, CA, United States
| | - Andrew G Zink
- Department of Biology, San Francisco State University, San Francisco, CA, United States
| | - Wesley Sparagon
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, Department of Oceanography and Sea Grant College Program, UUniversity of Hawai'i at Mānoa, HI, United States
| | - Tiffany A Yap
- Center for Biological Diversity, Oakland, CA, United States
| | - Hasan Sulaeman
- Department of Biology, San Francisco State University, San Francisco, CA, United States
| | - Michelle S Koo
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA, United States
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, San Francisco, CA, United States.,Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA, United States
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18
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Woodhams DC, Madison JD, Bletz MC, McCartney J, LaBumbard BC, Whetstone R, McDonnell NB, Preissler K, Sabino-Pinto J, Piovia-Scott J. Responsible biosecurity and risk mitigation for laboratory research on emerging pathogens of amphibians. DISEASES OF AQUATIC ORGANISMS 2021; 147:141-148. [PMID: 34913442 DOI: 10.3354/dao03636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The increasing study of emerging wildlife pathogens and a lack of policy or legislation regulating their translocation and use has heightened concerns about laboratory escape, species spillover, and subsequent epizootics among animal populations. Responsible self-regulation by research laboratories, in conjunction with institutional-level safeguards, has an important role in mitigating pathogen transmission and spillover, as well as potential interspecies pathogenesis. A model system in disease ecology that highlights these concerns and related amelioration efforts is research focused on amphibian emerging infectious diseases. Whereas laboratory escape of amphibian pathogens has not been reported and may be rare compared with introduction events from trade or human globalization, the threat that novel disease outbreaks with mass mortality effects pose to wild populations warrants thorough biosecurity measures to ensure containment and prevent spillover. Here, we present a case study of the laboratory biosecurity concerns for the emerging amphibian fungal pathogen Batrachochytrium salamandrivorans. We conclude that proactive biosecurity strategies are needed to integrate researcher and institutional oversight of aquatic wildlife pathogens generally, and we call for increased national and international policy and legislative enforcement. Furthermore, taking professional responsibility beyond current regulations is needed as development of legal guidance can be slow at national and international levels. We outline the need for annual laboratory risk assessments, comprehensive training for all laboratory personnel, and appropriate safeguards specific to pathogens under study. These strategies are critical for upholding the integrity and credibility of the scientific community and maintaining public support for research on wildlife diseases.
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Affiliation(s)
- Douglas C Woodhams
- Biology Department, University of Massachusetts Boston, Boston, MA 02125, USA
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19
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Epidemiology of Ophidiomycosis In Lake Erie Watersnakes (Nerodia sipedon insularum). J Wildl Dis 2021; 58:100-113. [PMID: 34818415 DOI: 10.7589/jwd-d-21-00111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/30/2021] [Indexed: 11/20/2022]
Abstract
Ophidiomycosis, caused by the fungus Ophidiomyces ophidiicola, is an infectious disease of wild and managed snakes worldwide. Lake Erie watersnakes (LEWS; Nerodia sipedon insularum) were listed as threatened under the US Endangered Species Act from 1999 to 2011 and were first diagnosed with ophidiomycosis in 2009. Our objective was to characterize the epidemiology of ophidiomycosis in LEWS. We hypothesized that the prevalence of skin lesions, O. ophidiicola DNA, and ophidiomycosis disease categories would show spatial and temporal variation and clustering, with higher prevalence at sites with greater human disturbance and prevalence increasing over time. Snakes were captured via visual encounter surveys at five sites across four islands and visually inspected for skin lesions suggestive of ophidiomycosis, and then body swabs were collected to detect O. ophidiicola DNA using the quantitative PCR assay. Each snake was assigned an ophidiomycosis category based on the presence of skin lesions and O. ophidiicola. We evaluated 837 LEWS between 2017 and 2020 and detected ophidiomycosis at all five sites. Logistic regression analysis showed temporal and spatial variation in disease, with higher risk of apparent ophidiomycosis (lesions present and O. ophidiicola detected) at Kelleys Island State Park, compared to all other sites; in May, compared to July; and in 2019, compared to 2018. The presence of emerging herbaceous wetlands, urban land change, and certain soil types increased the odds of both lesion presence and quantitative PCR detection of O. ophidiicola. Overall, ophidiomycosis epidemiology varied among sites: the disease appeared to be endemic at most sites and emerging at one site. Ongoing efforts to monitor population health and mortality associated with disease prevalence are needed to inform mitigation aimed at reducing the impact of ophidiomycosis in LEWS.
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20
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García‐Rodríguez A, Basanta MD, García‐Castillo MG, Zumbado‐Ulate H, Neam K, Rovito S, Searle CL, Parra‐Olea G. Anticipating the potential impacts of
Batrachochytrium salamandrivorans
on Neotropical salamander diversity. Biotropica 2021. [DOI: 10.1111/btp.13042] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Adrián García‐Rodríguez
- Departamento de Zoología Instituto de Biología Universidad Nacional Autónoma de México Ciudad de México México
- BioInvasions, Global Change, Macroecology‐Group Department of Botany and Biodiversity Research University of Vienna Vienna Austria
| | - M. Delia Basanta
- Departamento de Zoología Instituto de Biología Universidad Nacional Autónoma de México Ciudad de México México
- Centro de Ciencias Genómicas Universidad Nacional Autónoma de México Cuernavaca Morelos México
| | - Mirna G. García‐Castillo
- Universidad Politécnica de Huatusco Huatusco Veracruz México
- Facultad de Ciencias Biológicas y Agropecuarias Región: Orizaba–Córdoba Universidad Veracruzana Amatlán de los Reyes Veracruz México
| | | | - Kelsey Neam
- Global Wildlife Conservation Austin Texas USA
- Amphibian Specialist Group IUCN Species Survival Commission USA
| | - Sean Rovito
- Unidad de Genómica Avanzada (Langebio) CINVESTAV Irapuato México
| | - Catherine L. Searle
- Department of Biological Sciences Purdue University West Lafayette Indiana USA
| | - Gabriela Parra‐Olea
- Departamento de Zoología Instituto de Biología Universidad Nacional Autónoma de México Ciudad de México México
- Amphibian Specialist Group IUCN Species Survival Commission USA
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21
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Kelly M, Pasmans F, Muñoz JF, Shea TP, Carranza S, Cuomo CA, Martel A. Diversity, multifaceted evolution, and facultative saprotrophism in the European Batrachochytrium salamandrivorans epidemic. Nat Commun 2021; 12:6688. [PMID: 34795258 PMCID: PMC8602665 DOI: 10.1038/s41467-021-27005-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 10/28/2021] [Indexed: 01/06/2023] Open
Abstract
While emerging fungi threaten global biodiversity, the paucity of fungal genome assemblies impedes thoroughly characterizing epidemics and developing effective mitigation strategies. Here, we generate de novo genomic assemblies for six outbreaks of the emerging pathogen Batrachochytrium salamandrivorans (Bsal). We reveal the European epidemic currently damaging amphibian populations to comprise multiple, highly divergent lineages demonstrating isolate-specific adaptations and metabolic capacities. In particular, we show extensive gene family expansions and acquisitions, through a variety of evolutionary mechanisms, and an isolate-specific saprotrophic lifecycle. This finding both explains the chytrid's ability to divorce transmission from host density, producing Bsal's enigmatic host population declines, and is a key consideration in developing successful mitigation measures.
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Affiliation(s)
- Moira Kelly
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium.
| | - Frank Pasmans
- grid.5342.00000 0001 2069 7798Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
| | - Jose F. Muñoz
- grid.66859.34Broad Institute of MIT and Harvard, Cambridge, 02142 MA USA
| | - Terrance P. Shea
- grid.66859.34Broad Institute of MIT and Harvard, Cambridge, 02142 MA USA
| | - Salvador Carranza
- grid.507636.10000 0004 0424 5398Institute of Evolutionary Biology (CSIC-UPF), 08003 Barcelona, Spain
| | - Christina A. Cuomo
- grid.66859.34Broad Institute of MIT and Harvard, Cambridge, 02142 MA USA
| | - An Martel
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium.
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22
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Mantzana-Oikonomaki V, Maan M, Sabino-Pinto J. Wildlife pathogen detection: evaluation of alternative DNA extraction protocols. Biol Methods Protoc 2021; 6:bpab018. [PMID: 34693021 PMCID: PMC8529346 DOI: 10.1093/biomethods/bpab018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/13/2021] [Accepted: 09/15/2021] [Indexed: 11/14/2022] Open
Abstract
Accurate detection of wildlife pathogens is critical in wildlife disease research. False negatives or positives can have catastrophic consequences for conservation and disease-mitigation decisions. Quantitative polymerase chain reaction is commonly used for molecular detection of wildlife pathogens. The reliability of this method depends on the effective extraction of the pathogen's DNA from host samples. A wildlife disease that has been in the centre of conservationist's attention is the amphibian disease Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Here, we compare the efficiency of a spin column extraction kit (QIAGEN), commonly used in Bd DNA extraction, to an alternative spin column kit (BIOKÈ) used in extractions from other types of samples, which is considerably cheaper but not typically used for Bd DNA extraction. Additionally, we explore the effect of an enzymatic pre-treatment on detection efficiency. Both methods showed similar efficiency when extracting Bd DNA from zoospores from laboratory-created cell-cultures, as well as higher efficiency when combined with the enzymatic pre-treatment. Our results indicate that selecting the optimal method for DNA extraction is essential to ensure minimal false negatives and reduce project costs.
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Affiliation(s)
| | - Martine Maan
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
| | - Joana Sabino-Pinto
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
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23
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Wang Y, Verbrugghe E, Meuris L, Chiers K, Kelly M, Strubbe D, Callewaert N, Pasmans F, Martel A. Epidermal galactose spurs chytrid virulence and predicts amphibian colonization. Nat Commun 2021; 12:5788. [PMID: 34608163 PMCID: PMC8490390 DOI: 10.1038/s41467-021-26127-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 09/09/2021] [Indexed: 02/08/2023] Open
Abstract
The chytrid fungal pathogens Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans cause the skin disease chytridiomycosis in amphibians, which is driving a substantial proportion of an entire vertebrate class to extinction. Mitigation of its impact is largely unsuccessful and requires a thorough understanding of the mechanisms underpinning the disease ecology. By identifying skin factors that mediate key events during the early interaction with B. salamandrivorans zoospores, we discovered a marker for host colonization. Amphibian skin associated beta-galactose mediated fungal chemotaxis and adhesion to the skin and initiated a virulent fungal response. Fungal colonization correlated with the skin glycosylation pattern, with cutaneous galactose content effectively predicting variation in host susceptibility to fungal colonization between amphibian species. Ontogenetic galactose patterns correlated with low level and asymptomatic infections in salamander larvae that were carried over through metamorphosis, resulting in juvenile mortality. Pronounced variation of galactose content within some, but not all species, may promote the selection for more colonization resistant host lineages, opening new avenues for disease mitigation.
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Affiliation(s)
- Yu Wang
- grid.5342.00000 0001 2069 7798Wildlife Health Ghent, Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Elin Verbrugghe
- grid.5342.00000 0001 2069 7798Wildlife Health Ghent, Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Leander Meuris
- grid.5342.00000 0001 2069 7798Center for Medical Biotechnology, Department of Biochemistry and Microbiology, VIB-Ghent University, Zwijnaarde, Belgium
| | - Koen Chiers
- grid.5342.00000 0001 2069 7798Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Moira Kelly
- grid.5342.00000 0001 2069 7798Wildlife Health Ghent, Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Diederik Strubbe
- grid.5342.00000 0001 2069 7798Terrestrial Ecology Unit, Department of Biology, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Nico Callewaert
- grid.5342.00000 0001 2069 7798Center for Medical Biotechnology, Department of Biochemistry and Microbiology, VIB-Ghent University, Zwijnaarde, Belgium
| | - Frank Pasmans
- grid.5342.00000 0001 2069 7798Wildlife Health Ghent, Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - An Martel
- grid.5342.00000 0001 2069 7798Wildlife Health Ghent, Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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24
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Bosch J, Martel A, Sopniewski J, Thumsová B, Ayres C, Scheele BC, Velo-Antón G, Pasmans F. Batrachochytrium salamandrivorans Threat to the Iberian Urodele Hotspot. J Fungi (Basel) 2021; 7:jof7080644. [PMID: 34436183 PMCID: PMC8400424 DOI: 10.3390/jof7080644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/02/2021] [Accepted: 08/05/2021] [Indexed: 12/17/2022] Open
Abstract
The recent introduction of the chytrid fungus Batrachochytrium salamandrivorans into northeastern Spain threatens salamander diversity on the Iberian Peninsula. We assessed the current epidemiological situation with extensive field sampling of urodele populations. We then sought to delineate priority regions and identify conservation units for the Iberian Peninsula by estimating the susceptibility of Iberian urodeles using laboratory experiments, evidence from mortality events in nature and captivity and inference from phylogeny. None of the 1395 field samples, collected between 2015 and 2021 were positive for Bsal and no Bsal-associated mortality events were recorded, in contrast to the confirmed occurrence of Bsal outbreak previously described in 2018. We classified five of eleven Iberian urodele species as highly susceptible, predicting elevated mortality and population declines following potential Bsal emergence in the wild, five species as intermediately susceptible with variable disease outcomes and one species as resistant to disease and mortality. We identified the six conservation units (i.e., species or lineages within species) at highest risk and propose priority areas for active disease surveillance and field biosecurity measures. The magnitude of the disease threat identified here emphasizes the need for region-tailored disease abatement plans that couple active disease surveillance to rapid and drastic actions.
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Affiliation(s)
- Jaime Bosch
- Biodiversity Research Institute (IMIB), University of Oviedo-Principality of Asturias-CSIC, 33600 Mieres, Spain;
- Museo Nacional de Ciencias Naturales-CSIC, 28006 Madrid, Spain
- Correspondence: ; Tel.: +34-6-777-724-02
| | - An Martel
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Poultry Diseases, Ghent University, B9820 Merelbeke, Belgium; (A.M.); (F.P.)
| | - Jarrod Sopniewski
- Fenner School of Environment and Society, Australian National University, Canberra 2601, Australia; (J.S.); (B.C.S.)
| | - Barbora Thumsová
- Biodiversity Research Institute (IMIB), University of Oviedo-Principality of Asturias-CSIC, 33600 Mieres, Spain;
- Museo Nacional de Ciencias Naturales-CSIC, 28006 Madrid, Spain
- Asociación Herpetologica Española, 28006 Madrid, Spain;
| | - Cesar Ayres
- Asociación Herpetologica Española, 28006 Madrid, Spain;
| | - Ben C. Scheele
- Fenner School of Environment and Society, Australian National University, Canberra 2601, Australia; (J.S.); (B.C.S.)
| | - Guillermo Velo-Antón
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal;
- Grupo GEA, Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, 36310 Vigo, Spain
| | - Frank Pasmans
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Poultry Diseases, Ghent University, B9820 Merelbeke, Belgium; (A.M.); (F.P.)
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25
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Beukema W, Erens J, Schulz V, Stegen G, Spitzen-van der Sluijs A, Stark T, Laudelout A, Kinet T, Kirschey T, Poulain M, Miaud C, Steinfartz S, Martel A, Pasmans F. Landscape epidemiology of Batrachochytrium salamandrivorans: reconciling data limitations and conservation urgency. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02342. [PMID: 33817953 DOI: 10.1002/eap.2342] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 12/01/2020] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
Starting in 2010, rapid fire salamander (Salamandra salamandra) population declines in northwestern Europe heralded the emergence of Batrachochytrium salamandrivorans (Bsal), a salamander-pathogenic chytrid fungus. Bsal poses an imminent threat to global salamander diversity owing to its wide host range, high pathogenicity, and long-term persistence in ecosystems. While there is a pressing need to develop further research and conservation actions, data limitations inherent to recent pathogen emergence obscure necessary insights into Bsal disease ecology. Here, we use a hierarchical modeling framework to describe Bsal landscape epidemiology of outbreak sites in light of these methodological challenges. Using model selection and machine learning, we find that Bsal presence is associated with humid and relatively cool, stable climates. Outbreaks are generally located in areas characterized by low landscape heterogeneity and low steepness of slope. We further find an association between Bsal presence and high trail density, suggesting that human-mediated spread may increase risk for spillover between populations. We then use distribution modeling to show that favorable conditions occur in lowlands influenced by the North Sea, where increased survey effort is needed to determine how Bsal impacts local newt populations, but also in hill- and mountain ranges in northeastern France and the lower half of Germany. Finally, connectivity analyses suggest that these hill- and mountain ranges may act as stepping stones for further spread southward. Our results provide initial insight into regional environmental conditions underlying Bsal epizootics, present updated invasibility predictions for northwestern Europe, and lead us to discuss a wide variety of potential survey and research actions needed to advance future conservation and mitigation efforts.
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Affiliation(s)
- Wouter Beukema
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
- Naturalis Biodiversity Center, P.O. Box␣9517, Leiden, 2300RA, the Netherlands
| | - Jesse Erens
- Naturalis Biodiversity Center, P.O. Box␣9517, Leiden, 2300RA, the Netherlands
| | - Vanessa Schulz
- Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Talstrasse 33, Leipzig, 04103, Germany
- Technische Universität Braunschweig, Division of Evolutionary Biology, Zoological Institute, Mendelssohnstrasse 4, Braunschweig, 38106, Germany
| | - Gwij Stegen
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | | | - Tariq Stark
- Reptile, Amphibian & Fish Conservation Netherlands (RAVON), Toernooiveld 1, Nijmegen, 6525ED, the Netherlands
| | - Arnaud Laudelout
- Reptile, Amphibian & Fish Conservation Netherlands (RAVON), Toernooiveld 1, Nijmegen, 6525ED, the Netherlands
| | - Thierry Kinet
- Natagora, Traverse des Muses 1, Namur, 5000, Belgium
| | - Tom Kirschey
- Nature and Biodiversity Conservation Union (NABU), Charitéstrasse 3, Berlin, 10117, Germany
| | - Marie Poulain
- Biogeography and Vertebrate Ecology, CEFE, EPHE-PSL, CNRS, University of Montpellier, Paul Valéry University Montpellier III, 1919 route de Mende, Montpellier, 34293, France
| | - Claude Miaud
- Biogeography and Vertebrate Ecology, CEFE, EPHE-PSL, CNRS, University of Montpellier, Paul Valéry University Montpellier III, 1919 route de Mende, Montpellier, 34293, France
| | - Sebastian Steinfartz
- Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Talstrasse 33, Leipzig, 04103, Germany
| | - An Martel
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Frank Pasmans
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
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26
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Connectivity of Alpine newt populations (Ichthyosaura alpestris) exacerbates the risk of Batrachochytrium salamandrivorans outbreaks in European fire salamanders (Salamandra salamandra). CONSERV GENET 2021. [DOI: 10.1007/s10592-021-01377-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractThe pathogenic chytrid fungus Batrachochytrium salamandrivorans (Bsal) was introduced from Asia to Europe, most likely via the pet trade. It is currently causing a severe local decline in populations of the European fire salamanders (Salamandra salamandra). Laboratory tests confirmed that all infected individuals succumbed to the disease within two weeks. Furthermore, mass mortality events in the wild were observed in Germany, Belgium and the Netherlands. Some newt species, including the Alpine newt (Ichthyosaura alpestris), can also become infected with Bsal. However, they seem to be ‘tolerant’ and can often survive the disease, but maintain an infectious load, which they could spread among connected populations. It is, therefore, hypothesized that this species functions as a vector of the disease and threatens syntopic populations of susceptible species such as the European fire salamander. To assess the risk of Alpine newts as vectors for Bsal, we sampled 233 individuals from 50 sites in 2017 and performed a genetic population connectivity analysis using microsatellites. The results showed that populations of Alpine newts are not spatially structured, suggesting high gene flow across the study area. Tests for Bsal of all Alpine newts and 150 individuals of two other newt species confirmed five infected individuals. Infected newts can thus function as reservoirs and vectors of Bsal and spread it through dispersal. As a result, the risk of European fire salamander declines in this region is further exacerbated by the connectivity of syntopic Alpine newt populations.
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27
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Bernard RF, Grant EHC. Rapid Assessment Indicates Context‐Dependent Mitigation for Amphibian Disease Risk. WILDLIFE SOC B 2021. [DOI: 10.1002/wsb.1198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Riley F. Bernard
- Department of Zoology and Physiology University of Wyoming Laramie WY 82071 USA
| | - Evan H. Campbell Grant
- United States Geological Survey, Eastern Ecological Science Center S. O. Conte Anadromous Fish Laboratory Turners Falls MA 01376 USA
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28
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29
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Plethodontid salamanders show variable disease dynamics in response to Batrachochytrium salamandrivorans chytridiomycosis. Biol Invasions 2021. [DOI: 10.1007/s10530-021-02536-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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Yannic G, Helfer V, Sermier R, Schmidt BR, Fumagalli L. Fine scale genetic structure in fire salamanders (Salamandra salamandra) along a rural-to-urban gradient. CONSERV GENET 2021. [DOI: 10.1007/s10592-021-01335-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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31
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Pereira KE, Woodley SK. Skin defenses of North American salamanders against a deadly salamander fungus. Anim Conserv 2021. [DOI: 10.1111/acv.12666] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- K. E. Pereira
- Department of Biological Sciences Duquesne University Pittsburgh PA USA
| | - S. K. Woodley
- Department of Biological Sciences Duquesne University Pittsburgh PA USA
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32
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Lastra González D, Baláž V, Chajma P, Vojar J. Surveying for Batrachochytrium salamandrivorans presence in Spanish captive collections of amphibians. DISEASES OF AQUATIC ORGANISMS 2020; 142:99-103. [PMID: 33269721 DOI: 10.3354/dao03535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Batrachochytrium salamandrivorans (Bsal), a pathogenic fungus causing the fatal disease chytridiomycosis in amphibians, was likely introduced to Europe through the trade in pet salamanders from Asia and then escaped into wild populations. Among European countries, Spain has a large number of private breeders and keepers of pet salamanders, and cases of Bsal in wild and captive populations already have been confirmed there. However, surveillance for the pathogen in Spanish collections of amphibians is sparse. Therefore, assisted by private owners and breeders, we surveyed 10 amphibian collections and analysed a total of 317 samples for presence of Bsal. All of our analyses yielded negative results. However, this apparent lack of Bsal cases in captivity should not encourage relaxation of vigilance, quarantine efforts or good practices. Because amphibian collections represent highly dynamic environments (animals are coming in and out), the pathogen could easily be introduced into a collection by new individuals. Any case of Bsal infection in captive animals could lead to its further spread to wild populations of susceptible species, potentially decimating them, and thus should be prevented.
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Affiliation(s)
- D Lastra González
- Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 00 Prague - Suchdol, Czech Republic
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33
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Towards a food web based control strategy to mitigate an amphibian panzootic in agricultural landscapes. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2020.e01314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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Instant killing of pathogenic chytrid fungi by disposable nitrile gloves prevents disease transmission between amphibians. PLoS One 2020; 15:e0241048. [PMID: 33119670 PMCID: PMC7595420 DOI: 10.1371/journal.pone.0241048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 10/07/2020] [Indexed: 12/03/2022] Open
Abstract
To prevent transmission of the pathogenic chytrid fungi Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal), hygiene protocols prescribe the single use of disposable gloves for handling amphibians. We discovered that rinse water from nitrile gloves instantly kills 99% of Bd and Bsal zoospores. Transmission experiments using midwife toads (Alytes obstetricans) and Bd, and Alpine newts (Ichthyosaura alpestris) and Bsal, show that the use of the same pair of gloves for 2 subsequent individuals does not result in significant transmission of any chytrid fungus. In contrast, handling infected amphibians bare-handed caused transmission of Bsal in 4 out of 10 replicates, but did not result in transmission of Bd. Based on the manufacturer’s information, high resolution mass spectrometry (HRMS) and colorimetric tests, calcium lactate and calcium nitrate were identified as compounds with antifungal activity against both Bd and Bsal. These findings corroborate the importance of wearing gloves as an important sanitary measure in amphibian disease prevention. If the highly recommended single use of gloves is not possible, handling multiple post-metamorphic amphibians with the same pair of nitrile gloves should still be preferred above bare-handed manipulation.
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35
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Beukema W, Pasmans F, Van Praet S, Ferri-Yáñez F, Kelly M, Laking AE, Erens J, Speybroeck J, Verheyen K, Lens L, Martel A. Microclimate limits thermal behaviour favourable to disease control in a nocturnal amphibian. Ecol Lett 2020; 24:27-37. [PMID: 33022129 DOI: 10.1111/ele.13616] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/15/2020] [Accepted: 09/07/2020] [Indexed: 11/28/2022]
Abstract
While epizootics increasingly affect wildlife, it remains poorly understood how the environment shapes most host-pathogen systems. Here, we employ a three-step framework to study microclimate influence on ectotherm host thermal behaviour, focusing on amphibian chytridiomycosis in fire salamanders (Salamandra salamandra) infected with the fungal pathogen Batrachochytrium salamandrivorans (Bsal). Laboratory trials reveal that innate variation in thermal preference, rather than behavioural fever, can inhibit infection and facilitate salamander recovery under humidity-saturated conditions. Yet, a 3-year field study and a mesocosm experiment close to the invasive Bsal range show that microclimate constraints suppress host thermal behaviour favourable to disease control. A final mechanistic model, that estimates range-wide, year-round host body temperature relative to microclimate, suggests that these constraints are rule rather than exception. Our results demonstrate how innate host defences against epizootics may remain constrained in the wild, which predisposes to range-wide disease outbreaks and population declines.
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Affiliation(s)
- Wouter Beukema
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Frank Pasmans
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Sarah Van Praet
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Francisco Ferri-Yáñez
- Department of Community Ecology, Helmholtz Centre for Environmental Research (UFZ), Theodor-Lieser-Strasse 4, Halle, 06120, Germany
| | - Moira Kelly
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Alexandra E Laking
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Jesse Erens
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Jeroen Speybroeck
- Research Institute for Nature and Forest - INBO, Havenlaan 88 bus 73, Brussels, 1000, Belgium
| | - Kris Verheyen
- Forest & Nature Lab, Department of Forest and Water Management, Ghent University, Geraardsbergsesteenweg 267, Gontrode, 9090, Belgium
| | - Luc Lens
- Terrestrial Ecology Unit, Ghent University, K. L, Ledeganckstraat 35, Ghent, 9000, Belgium
| | - An Martel
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
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36
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Dampened virulence and limited proliferation of Batrachochytrium salamandrivorans during subclinical infection of the troglobiont olm (Proteus anguinus). Sci Rep 2020; 10:16480. [PMID: 33020584 PMCID: PMC7536193 DOI: 10.1038/s41598-020-73800-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/15/2020] [Indexed: 11/25/2022] Open
Abstract
Emerging infections add to existing threats to the survival of amphibians worldwide. The olm (Proteus anguinus) is a vulnerable, troglobiont urodele species with a small European range and restricted to underground karstic systems. Population declines to emerging threats like the chytrid fungus Batrachochytrium salamandrivorans, are likely to go unnoticed due to inaccessibility of the species’ habitat. We here studied the interaction between olms and B. salamandrivorans. Experimental inoculation of olms resulted in low-level, asymptomatic but persistent infections, with limbs as predilection sites. The lack of exponential fungal growth in the olms’ epidermis correlated with limited fungal proliferation and dampened virulence gene expression after exposure to olm skin compounds. The olm is one of few western Palearctic urodeles that is tolerant to B. salamandrivorans infection and may act as a subterranean disease reservoir, yet costs of subclinical infection may compromise olm fitness on the long term.
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Li Z, Martel A, Bogaerts S, Göçmen B, Pafilis P, Lymberakis P, Woeltjes T, Veith M, Pasmans F. Landscape Connectivity Limits the Predicted Impact of Fungal Pathogen Invasion. J Fungi (Basel) 2020; 6:E205. [PMID: 33022972 PMCID: PMC7712934 DOI: 10.3390/jof6040205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 12/11/2022] Open
Abstract
Infectious diseases are major drivers of biodiversity loss. The risk of fungal diseases to the survival of threatened animals in nature is determined by a complex interplay between host, pathogen and environment. We here predict the risk of invasion of populations of threatened Mediterranean salamanders of the genus Lyciasalamandra by the pathogenic chytrid fungus Batrachochytrium salamandrivorans by combining field sampling and lab trials. In 494 samples across all seven species of Lyciasalamandra, B. salamandrivorans was found to be absent. Single exposure to a low (1000) number of fungal zoospores resulted in fast buildup of lethal infections in three L. helverseni. Thermal preference of the salamanders was well within the thermal envelope of the pathogen and body temperatures never exceeded the fungus' thermal critical maximum, limiting the salamanders' defense opportunities. The relatively low thermal host preference largely invalidates macroclimatic based habitat suitability predictions and, combined with current pathogen absence and high host densities, suggests a high probability of local salamander population declines upon invasion by B. salamandrivorans. However, the unfavorable landscape that shaped intraspecific host genetic diversity, lack of known alternative hosts and rapid host mortality after infection present barriers to further, natural pathogen dispersal between populations and thus species extinction. The risk of anthropogenic spread stresses the importance of biosecurity in amphibian habitats.
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Affiliation(s)
- Zhimin Li
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B9820 Merelbeke, Belgium; (Z.L.); (A.M.)
| | - An Martel
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B9820 Merelbeke, Belgium; (Z.L.); (A.M.)
| | | | - Bayram Göçmen
- Faculty of Science, Department of Biology, Zoology Section, Ege University, TR-35100 İzmir, Turkey
| | - Panayiotis Pafilis
- Department of Zoology and Marine Biology, School of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, Ilissia, 15784 Athens, Greece;
| | - Petros Lymberakis
- Natural History Museum of Crete, School of Sciences and Engineering, University of Crete, Knossos Ave., 1409 Irakleio, Greece;
| | | | - Michael Veith
- Department of Biogeography, Trier University, Universitätsring 15, D-54296 Trier, Germany;
| | - Frank Pasmans
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B9820 Merelbeke, Belgium; (Z.L.); (A.M.)
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38
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Batrachochytrium salamandrivorans (Bsal) not detected in an intensive survey of wild North American amphibians. Sci Rep 2020; 10:13012. [PMID: 32747670 PMCID: PMC7400573 DOI: 10.1038/s41598-020-69486-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 05/22/2020] [Indexed: 11/22/2022] Open
Abstract
The salamander chytrid fungus (Batrachochytrium salamandrivorans [Bsal]) is causing massive mortality of salamanders in Europe. The potential for spread via international trade into North America and the high diversity of salamanders has catalyzed concern about Bsal in the U.S. Surveillance programs for invading pathogens must initially meet challenges that include low rates of occurrence on the landscape, low prevalence at a site, and imperfect detection of the diagnostic tests. We implemented a large-scale survey to determine if Bsal was present in North America designed to target taxa and localities where Bsal was determined highest risk to be present based on species susceptibility and geography. Our analysis included a Bayesian model to estimate the probability of occurrence of Bsal given our prior knowledge of the occurrence and prevalence of the pathogen. We failed to detect Bsal in any of 11,189 samples from 594 sites in 223 counties within 35 U.S. states and one site in Mexico. Our modeling indicates that Bsal is highly unlikely to occur within wild amphibians in the U.S. and suggests that the best proactive response is to continue mitigation efforts against the introduction and establishment of the disease and to develop plans to reduce impacts should Bsal establish.
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39
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Haynes E, Chandler HC, Stegenga BS, Adamovicz L, Ospina E, Zerpa-Catanho D, Stevenson DJ, Allender MC. Ophidiomycosis surveillance of snakes in Georgia, USA reveals new host species and taxonomic associations with disease. Sci Rep 2020; 10:10870. [PMID: 32616837 PMCID: PMC7331741 DOI: 10.1038/s41598-020-67800-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 06/09/2020] [Indexed: 01/11/2023] Open
Abstract
Ophidiomycosis (snake fungal disease) is caused by the fungus Ophidiomyces ophiodiicola and threatens snake health worldwide. It has been documented throughout the eastern United States and severe cases have recently been reported in Georgia, USA. To evaluate disease distribution and prevalence in this state, 786 free-ranging snakes were examined for skin lesions consistent with ophidiomycosis and swabbed to detect O. ophiodiicola DNA using qPCR. Sampled snakes represented 34 species and 4 families; 27.5% had skin lesions, 13.3% were positive for O. ophiodiicola DNA, and 77.8% of the qPCR positive individuals had skin lesions. This is the first report of O. ophiodiicola in five of the 22 species that were qPCR positive. Multinomial logistic regression modeling indicated that Drymarchon couperi had a higher relative risk of apparent ophidiomycosis (lesions present and qPCR positive), and the best models predicting qPCR result and ophidiomycosis category included individual factors and excluded temporal and spatial factors. Phylogeny-based bipartite network analysis showed that Nerodia erythrogaster, Nerodia taxispilota, and D. couperi had the highest prevalence of apparent ophidiomycosis; this category was more prevalent in the subfamily Colubrinae and less prevalent in Natricinae. These results provide important information about ophidiomycosis epidemiology, which has implications for snake conservation.
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Affiliation(s)
- Ellen Haynes
- Wildlife Epidemiology Laboratory, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
| | | | | | - Laura Adamovicz
- Wildlife Epidemiology Laboratory, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Emilie Ospina
- Wildlife Epidemiology Laboratory, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | | | - Dirk J Stevenson
- The Orianne Society, Tiger, GA, USA
- Altamaha Environmental Consulting, Hinesville, GA, USA
| | - Matthew C Allender
- Wildlife Epidemiology Laboratory, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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40
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McDonald CA, Longo AV, Lips KR, Zamudio KR. Incapacitating effects of fungal coinfection in a novel pathogen system. Mol Ecol 2020; 29:3173-3186. [PMID: 32310322 DOI: 10.1111/mec.15452] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 03/16/2020] [Accepted: 04/08/2020] [Indexed: 12/20/2022]
Abstract
As globalization lowers geographic barriers to movement, coinfection with novel and enzootic pathogens is increasingly likely. Novel and enzootic pathogens can interact synergistically or antagonistically, leading to increased or decreased disease severity. Here we examine host immune responses to coinfection with two closely related fungal pathogens: Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal). Both pathogens have had detrimental effects on amphibian populations, with Bd now largely enzootic, while Bsal is currently spreading and causing epizootics. Recent experimental work revealed that newts coinfected with Bd and Bsal had significantly higher mortality than those infected with either pathogen alone. Here we characterize host immunogenomic responses to chytrid coinfection relative to single infection. Across several classes of immune genes including pattern recognition receptors, cytokines, and MHC, coinfected host gene expression was weakly upregulated or comparable to that seen in single Bd infection, but significantly decreased when compared to Bsal infection. Combined with strong complement pathway downregulation and keratin upregulation, these results indicate that coinfection with Bd and Bsal compromises immune responses active against Bsal alone. As Bsal continues to invade naïve habitats where Bd is enzootic, coinfection will be increasingly common. If other Bd-susceptible species in the region have similar responses, interactions between the two pathogens could cause severe population and community-level declines.
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Affiliation(s)
- Cait A McDonald
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | - Ana V Longo
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Karen R Lips
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Kelly R Zamudio
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
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Malagon DA, Melara LA, Prosper OF, Lenhart S, Carter ED, Fordyce JA, Peterson AC, Miller DL, Gray MJ. Host density and habitat structure influence host contact rates and Batrachochytrium salamandrivorans transmission. Sci Rep 2020; 10:5584. [PMID: 32221329 PMCID: PMC7101388 DOI: 10.1038/s41598-020-62351-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 03/11/2020] [Indexed: 12/22/2022] Open
Abstract
Batrachochytrium salamandrivorans (Bsal) is an emerging invasive pathogen that is highly pathogenic to salamander species. Modeling infection dynamics in this system can facilitate proactive efforts to mitigate this pathogen's impact on North American species. Given its widespread distribution and high abundance, the eastern newt (Notophthalmus viridescens) has the potential to significantly influence Bsal epidemiology. We designed experiments to 1) estimate contact rates given different host densities and habitat structure and 2) estimate the probability of transmission from infected to susceptible individuals. Using parameter estimates from data generated during these experiments, we modeled infection and disease outcomes for a population of newts using a system of differential equations. We found that host contact rates were density-dependent, and that adding habitat structure reduced contacts. The probability of Bsal transmission given contact between newts was very high (>90%) even at early stages of infection. Our simulations show rapid transmission of Bsal among individuals following pathogen introduction, with infection prevalence exceeding 90% within one month and >80% mortality of newts in three months. Estimates of basic reproductive rate (R0) of Bsal for eastern newts were 1.9 and 3.2 for complex and simple habitats, respectively. Although reducing host density and increasing habitat complexity might decrease transmission, these management strategies may be ineffective at stopping Bsal invasion in eastern newt populations due to this species’ hyper-susceptibility.
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Affiliation(s)
- Daniel A Malagon
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - Luis A Melara
- Department of Mathematics, Shippensburg University, Shippensburg, PA, 17257, USA
| | - Olivia F Prosper
- Department of Mathematics, University of Kentucky, Lexington, KY, 40506, USA.,Department of Mathematics, University of Tennessee, Knoxville, TN, 37996, USA
| | - Suzanne Lenhart
- Department of Mathematics, University of Tennessee, Knoxville, TN, 37996, USA
| | - Edward Davis Carter
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - J A Fordyce
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Anna C Peterson
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - Debra L Miller
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA.,Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, 37996, USA
| | - Matthew J Gray
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA.
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42
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Barnhart KL, Bletz MC, LaBumbard BC, Tokash-Peters AG, Gabor CR, Woodhams DC. Batrachochytrium salamandrivorans ELICITS ACUTE STRESS RESPONSE IN SPOTTED SALAMANDERS BUT NOT INFECTION OR MORTALITY. Anim Conserv 2020; 23:533-546. [PMID: 33071596 DOI: 10.1111/acv.12565] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The emerging fungal pathogen Batrachochytrium salamandrivorans (Bsal) is a major threat to amphibian species worldwide with potential to infect many species if it invades salamander biodiversity hotspots in the Americas. Bsal can cause the disease chytridiomycosis, and it is important to assess the risk of Bsal-induced chytridiomycosis to species in North America. We evaluated the susceptibility to Bsal of the common and widespread spotted salamander, Ambystoma maculatum, across life history stages and monitored the effect of Bsal exposure on growth rate and response of the stress hormone, corticosterone. We conclude that spotted salamanders appear resistant to Bsal because they showed no indication of disease or infection, and experienced minor effects on growth upon exposure. While we focused on a single population for this study, results were consistent across conditions of exposure including high or repeated doses of Bsal, life-stage at exposure, environmental conditions including two temperatures and two substrates, and promoting pathogen infectivity by conditioning Bsal cultures with thyroid hormone. Exposure to high levels of Bsal elicited an acute but not chronic increase in corticosterone in spotted salamanders, and reduced growth. We hypothesize that the early acute increase in corticosterone facilitated mounting an immune response to the pathogen, perhaps through immunoredistribution to the skin, but further study is needed to determine immune responses to Bsal. These results will contribute to development of appropriate Bsal management plans to conserve species at risk of emerging disease.
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Affiliation(s)
- Kelly L Barnhart
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Molly C Bletz
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Brandon C LaBumbard
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Amanda G Tokash-Peters
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Caitlin R Gabor
- Texas State University, Department of Biology, 601 University Drive, San Marcos, TX 78666
| | - Douglas C Woodhams
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
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Canessa S, Bozzuto C, Pasmans F, Martel A. Quantifying the burden of managing wildlife diseases in multiple host species. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2019; 33:1131-1140. [PMID: 30868671 DOI: 10.1111/cobi.13313] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/20/2018] [Accepted: 01/24/2019] [Indexed: 06/09/2023]
Abstract
Mitigation of infectious wildlife diseases is especially challenging where pathogens affect communities of multiple host species. Although most ecological studies recognize the challenge posed by multiple-species pathogens, the implications for management are typically assessed only qualitatively. Translating the intuitive understanding that multiple host species are important into practice requires a quantitative assessment of whether and how secondary host species should also be targeted by management and the effort this will require. Using a multiple-species compartmental model, we determined analytically whether and how intensively secondary host species should be managed to prevent outbreaks in focal hosts based on the reproduction number of individual host species and between-species transmission rates. We applied the model to the invasive pathogenic fungus Batrachochytrium salamandrivorans in a 2-host system in northern Europe. Avoiding a disease outbreak in the focal host (fire salamanders [Salamandra salamandra]) was impossible unless management also heavily targeted the secondary host (alpine newts [Ichthyosaura alpestris]). Preventing an outbreak in the community required targeted removal of at least 80% of each species. This proportion increased to 90% in the presence of an environmental reservoir of B. salamandrivorans and when the proportion of individuals removed could not be adjusted for different host species (e.g., when using traps that are not species specific). We recommend the focus of disease-mitigation plans should shift from focal species to the community level and calculate explicitly the management efforts required on secondary host species to move beyond the simple intuitive understanding that multiple host species may all influence the system. Failure to do so may lead to underestimating the magnitude of the effort required and ultimately to suboptimal or futile management attempts.
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Affiliation(s)
- Stefano Canessa
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Claudio Bozzuto
- Wildlife Analysis GmbH, Oetlisbergstrasse 38, 8053, Zurich, Switzerland
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
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Carter ED, Miller DL, Peterson AC, Sutton WB, Cusaac JPW, Spatz JA, Rollins‐Smith L, Reinert L, Bohanon M, Williams LA, Upchurch A, Gray MJ. Conservation risk of
Batrachochytrium salamandrivorans
to endemic lungless salamanders. Conserv Lett 2019. [DOI: 10.1111/conl.12675] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Edward Davis Carter
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Debra L. Miller
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
- Department of Biomedical and Diagnostic Sciences, College of Veterinary MedicineUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Anna C. Peterson
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - William B. Sutton
- Department of Agricultural and Environmental SciencesTennessee State University Nashville Tennessee
| | - Joseph Patrick W. Cusaac
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Jennifer A. Spatz
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Louise Rollins‐Smith
- Department of PathologyMicrobiology & ImmunologyVanderbilt University Nashville Tennessee
| | - Laura Reinert
- Department of PathologyMicrobiology & ImmunologyVanderbilt University Nashville Tennessee
| | - Markese Bohanon
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Lori A. Williams
- North Carolina Wildlife Resources Commission Raleigh North Carolina
| | | | - Matthew J. Gray
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
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45
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Hettyey A, Ujszegi J, Herczeg D, Holly D, Vörös J, Schmidt BR, Bosch J. Mitigating Disease Impacts in Amphibian Populations: Capitalizing on the Thermal Optimum Mismatch Between a Pathogen and Its Host. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00254] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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46
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The importance of biological plausibility for data poor models in the face of an immediate threat by an emerging infectious disease: a reply to Katz and Zellmer (2018). Biol Invasions 2019. [DOI: 10.1007/s10530-019-02035-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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47
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Knepper J, Lüddecke T, Preißler K, Vences M, Schulz S. Isolation and Identification of Alkaloids from Poisons of Fire Salamanders ( Salamandra salamandra). JOURNAL OF NATURAL PRODUCTS 2019; 82:1319-1324. [PMID: 31074997 DOI: 10.1021/acs.jnatprod.9b00065] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Fire salamanders ( Salamandra salamandra) are conspicuously colored amphibians secreting a skin poison that contains unique steroid alkaloids such as samandarine (1) and samadarone (2), exhibiting toxic as well as antimicrobial activities. Because of their antipredatory and anti-infectious functions, alkaloids from Salamandra poison are of interest with regard to the threat that the lethal fungus Batrachochytrium salamandrivorans ( Bsal) poses to salamanders. Nevertheless, reliable data on the biological activity of Salamandra alkaloids are scarce, in part due to the difficulty to obtain and study those substances. Thus, isolation of pure salamander alkaloids is an important task that might directly contribute to the understanding of Bsal infections. Here we present a noninvasive isolation procedure for samandarine (1) and O-acetylsamandarine (3), as well as for two new alkaloids, O-3-hydroxybutanoylsamandarine (4) and samanone (6), using HPLC. For the first time, high-field NMR data are presented for these alkaloids. Analysis using GC/MS and ESI+-MS, provided important information on the structural variability of these salamander alkaloids.
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Affiliation(s)
- Janosch Knepper
- Institute of Organic Chemistry , Technische Universität Braunschweig , Hagenring 30 , 38106 Braunschweig , Germany
| | - Tim Lüddecke
- Animal Venomics Research Group , Fraunhofer Institute for Molecular Biology and Applied Ecology , Winchesterstraße 2 , 35394 Gießen , Germany
- Zoological Institute , Technische Universität Braunschweig , Mendelssohnstraße 4 , 38106 Braunschweig , Germany
| | - Kathleen Preißler
- Zoological Institute , Technische Universität Braunschweig , Mendelssohnstraße 4 , 38106 Braunschweig , Germany
| | - Miguel Vences
- Zoological Institute , Technische Universität Braunschweig , Mendelssohnstraße 4 , 38106 Braunschweig , Germany
| | - Stefan Schulz
- Institute of Organic Chemistry , Technische Universität Braunschweig , Hagenring 30 , 38106 Braunschweig , Germany
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48
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Sabino-Pinto J, Martel A, Pasmans F, Steinfartz S, Vences M. Pooling skin swabs does not inhibit qPCR detection of amphibian chytrid infection. PLoS One 2019; 14:e0214405. [PMID: 30939146 PMCID: PMC6445426 DOI: 10.1371/journal.pone.0214405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 03/12/2019] [Indexed: 11/18/2022] Open
Abstract
Immediate and reliable pathogen detection in large numbers of samples is essential in wildlife disease monitoring and is often realized by DNA-based techniques. Pooling samples increases processing efficiency and reduces processing costs, and has been suggested as a viable technique for quantitative PCR detection of fungal amphibian pathogens of the genus Batrachochytrium. For these fungi, this diagnostic method has been validated by in vitro set ups that provided controlled test conditions but did not take into account potential effects from amphibian skin compounds (e.g. skin secretions and Microbiota) on the approach. Some of these skin compounds are known to cause PCR inhibition in single sample applications and could lead to false negative reactions and thereby hamper pathogen detection. In this study we examined the effect of skin compounds on the pooled extraction method by swabbing individuals of seven amphibian species (one Anura and six Caudata) prior to the inoculation of the swabs with chytrid zoospores. For each species, swabs were extracted in pools of different sizes (from one to four swabs) with only one swab per pool being inoculated with zoospores. There were no significant differences regarding the ability to detect zoospores when comparing pool sizes for any species, with a tendency for more false negatives when the inoculated swab had been inoculated with a single zoospore. This study provides further in vivo evidence for the viability of the pooled extraction method for DNA-based detection of pathogens.
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Affiliation(s)
- Joana Sabino-Pinto
- Zoological Institute, Braunschweig University of Technology, Braunschweig, Germany
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Sebastian Steinfartz
- Zoological Institute, Braunschweig University of Technology, Braunschweig, Germany.,University of Leipzig, Institute of Biology, Molecular Evolution and Systematics of Animals, Leipzig, Germany
| | - Miguel Vences
- Zoological Institute, Braunschweig University of Technology, Braunschweig, Germany
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49
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Longo AV, Fleischer RC, Lips KR. Double trouble: co-infections of chytrid fungi will severely impact widely distributed newts. Biol Invasions 2019. [DOI: 10.1007/s10530-019-01973-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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50
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Apparent absence of Batrachochytrium salamandrivorans in wild urodeles in the United Kingdom. Sci Rep 2019; 9:2831. [PMID: 30862900 PMCID: PMC6414544 DOI: 10.1038/s41598-019-39338-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 01/18/2019] [Indexed: 11/09/2022] Open
Abstract
Whether an infectious disease threat to wildlife arises from pathogen introduction or the increased incidence of an already-present agent informs mitigation policy and actions. The prior absence of a pathogen can be difficult to establish, particularly in free-living wildlife. Subsequent to the epidemic emergence of the fungus, Batrachochytrium salamandrivorans (Bsal), in mainland Europe in 2010 and prior to its detection in captive amphibians in the United Kingdom (UK), we tested archived skin swabs using a Bsal-specific qPCR. These samples had been collected in 2011 from 2409 wild newts from ponds across the UK. All swabs were negative for Bsal. Bayesian hierarchical modelling suggests that Bsal was absent from, or present at very low levels in, these ponds at the time of sampling. Additionally, surveillance of newt mortality incidents, 2013-2017, failed to detect Bsal. As this pathogen has been shown to be widespread in British captive amphibian collections, there is an urgent need to raise awareness of the importance of effective biosecurity measures, especially amongst people with captive amphibians, to help minimise the risk of Bsal spreading to the wild. Continued and heightened wild amphibian disease surveillance is a priority to provide an early warning system for potential incursion events.
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