Historical dynamics of Batrachochytrium dendrobatidis in Amazonia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The Amazon forest is known for its astonishing amphibian diversity, yet the potential distribution and underlying impacts of the most important amphibian pathogen is unknown for most of Amazonia. In this retrospective survey of preserved Leptodactylus frogs, collected over a 119 yr period, we used quantitative PCR to detect the fungal pathogen Batrachochytrium dendrobatidis (Bd) and performed spatial scan analyses to identify spatiotemporal clusters of Bd. We also quantified the potential effect of environmental factors on the likelihood of Bd occurrence and generated an updated suitability map for Bd in the Amazon that included our retrospective sampling. We detected Bd in lowland Amazon as early as 1935, in the state of Para, Brazil, and we found low prevalence (approximate to 3.8%) over time. We identified two statistically significant spatiotemporal clusters of Bd: a recent and narrow cluster in the Amazon River delta and a spatiotemporally broad cluster in the southern edge of Amazon and Brazilian savanna. Furthermore, we found an increase in Bd-positive samples in the southwestern Amazon after the 1990s, coinciding with reported amphibian declines in neighboring high elevation sites on Andean slopes of Peru. Spatial regressions indicated that higher human interference, higher precipitation, and lower temperatures were significant predictors of Bd occurrence. Environmental niche modeling predicted some narrow areas of suitable climates along the Amazon's periphery and generally low climatic suitability for Bd in the central Amazon; although, we found clusters of Bd-positive samples with unexpectedly high infection loads in areas of predicted low suitability. Our study indicates that accelerated human development may put Amazonian amphibians at risk from Bd introductions, and it highlights the potential need to monitor Bd dynamics near Amazonian port cities.The Amazon forest is known for its astonishing amphibian diversity, yet the potential distribution and underlying impacts of the most important amphibian pathogen is unknown for most of Amazonia. In this retrospective survey of preserved Leptodactylus fro3910954960CNQP - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)312895/2014-3405285/2013-2302589/2013-92013/50741-7302518/2013-4We thank T. S. Jenkinson, and M. F. K. Becker for feedback on the manuscriptN. Pupin, A. Mesquita, E. Garcia, D. B. Delgado T. Carvalho, P. Mourao, A. F. R. Missassi, and L. F. Moreno for help with swabbing the specimens. Christopher J. Raxworthy, Da

A lizard acting as carrier of the amphibian-killing chytrid Batrachochytrium dendrobatidis in southern Brazil

Fungal infections are causing widespread population declines and extinctions in all vertebrate classes. Among them, an important fungal disease chytridiomycosis, caused by the pathogenic chytrid Batrachochytrium dendrobatidis (Bd). With an aquatic infectious phase, Bd does not survive desiccation for long, but may be transported by non-amphibian carriers. Such mechanism is key to understand amphibian-chytrid dynamics and may contribute to local amphibian conservation action plans. Therefore, we surveyed Bd in reptiles from two different Brazilian rainforests, looking for possible Bd carriers. We sampled 35 individuals belonging to 11 squamate families, five from the Atlantic Forest and 30 from the Amazon. We detected Bd in one adult lizard, Placosoma glabellum. This lizard feeds, shelters, and breeds in the leaf-litter, and moves between Atlantic Forest streams. Hence, it may be carrying Bd from stream to stream, and also spreading the pathogen to direct-developing amphibians, which have no contact with water bodies and are more susceptible to chytridiomycosis than aquatic species. This is the first record of a non-amphibian chytrid carrier in South America. We suggest that additional field and museum samplings will contribute to understand whether Bd can actually infect reptiles, and how reptile carriers can affect chytrid dynamics in the wild

Disentangling host, pathogen, and environmental determinants of a recently emerged wildlife disease: lessons from the first 15 years of amphibian chytridiomycosis research

The amphibian fungal disease chytridiomycosis, which affects species across all continents, recently emerged as one of the greatest threats to biodiversity. Yet, many aspects of the basic biology and epidemiology of the pathogen, Batrachochytrium dendrobatidis (Bd), are still unknown, such as when and from where did Bd emerge and what is its true ecological niche? Here, we review the ecology and evolution of Bd in the Americas and highlight controversies that make this disease so enigmatic. We explore factors associated with variance in severity of epizootics focusing on the disease triangle of host susceptibility, pathogen virulence, and environment. Reevaluating the causes of the panzootic is timely given the wealth of data on Bd prevalence across hosts and communities and the recent discoveries suggesting co‐evolutionary potential of hosts and Bd. We generate a new species distribution model for Bd in the Americas based on over 30,000 records and suggest a novel future research agenda. Instead of focusing on pathogen “hot spots,” we need to identify pathogen “cold spots” so that we can better understand what limits the pathogen's distribution. Finally, we introduce the concept of “the Ghost of Epizootics Past” to discuss expected patterns in postepizootic host communities.We review the ecology and evolution of amphibian fungal disease chytridiomycosis in the Americas, where it has recently emerged as one of the greatest threats to biodiversity and highlight controversies that make this disease so enigmatic. We explore factors associated with variance in severity of epizootics focusing on the disease triangle of host susceptibility, pathogen virulence, and environment. We generate a new species distribution model for Bd in the Americas based on over 30,000 records, which suggests emphasis needs to be placed on studying pathogen “cold spots” so that we can better understand what biotic and abiotic factors limit the pathogen's distribution.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113682/1/ece31672_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/113682/2/ece31672.pd

Preliminary inventory of the anuran fauna of the Mata Estrela Private Natural Heritage Reserve, in the Atlantic Forest of the State of Rio Grande do Norte, Brazil

Tropical regions harbor the highest amphibian biodiversity, nevertheless, information on species composition is lacking in most areas yet these baseline data are essential to guide conservation strategies. The goal of the present study was to survey the anurans of a Private Natural Heritage Reserve named Mata Estrela, a fragment of about 26 km2 in the Northern Atlantic Forest, Brazil. The study was carried out as an active census in June 2015. We found 27 anuran species assigned to five families: Bufonidae (2 spp.), Craugastoridae (1 sp.), Hylidae (11 spp.), Leptodactylidae (12 spp.) and Phyllomedusidae (1 sp.). All species are widespread in the Atlantic forest as well as in other South American ecoregions. Descriptions of local diversity such as this one are a fundamental baseline for conservation work and are especially needed in the northern limits of the Atlantic forest, for which there is still a huge lack of biological knowledge.Asociación Herpetológica Argentin

Novel findings on the impact of chytridiomycosis on the cardiac function of anurans: sensitive vs. tolerant species

Background Understanding of the physiological effects of chytridiomycosis is crucial to worldwide amphibian conservation. Therefore, we analyzed the cardiac function of two anuran species (Xenopus laevis and Physalaemus albonotatus) with different susceptibilities to infection by the causative agent of chytridiomycosis, Batrachochytrium dendrobatidis (hereafter Bd). Methods We analyzed the in situ heart rate (fH - bpm), relative ventricular mass (RVM -%), and Ca2+ handling in heart of Bd infected animals compared to uninfected controls of both study species. Results Bd infection resulted in a 78% decrease in contraction force values in P. albonotatus when compared to the less susceptible X. laevis. This negative effect was even more evident (82%) for the cardiac pumping capacity. The time to reach peak tension was 125% longer in P. albonotatus than in X. laevis, and cardiac relaxation was 57% longer. Discussion These results indicate a delay in the cardiac cycle of P. albonotatus on a beat-to-beat basis, which was corroborated by the bradycardia observed in situ. In summary, Bd-sensitive species present impaired cardiac function, which could be a factor in mortality risk. The more pronounced effects of Bd in P. albonotatus may not only result from electrolyte imbalance, as previously reported, but also could be an effect of toxins produced by Bd. For X. laevis, the ability to promote cardiac adjustments seems to be an important homeostatic feature that allows greater tolerance to chytridiomycosis. This study provides new physiological mechanisms underlying the tolerance or susceptibility of amphibian species to chytridiomycosis, which determine their adaptability to survive in the affected environments

Development and worldwide use of non-lethal, and minimal population-level impact, protocols for the isolation of amphibian chytrid fungi

T.W.J.G., M.C.F., D.S.S., A.L., E.C., F.C.C., J.B., A.A.C., C.M., F.S., B.R.S., S.O., were supported through the Biodiversa project RACE: Risk Assessment of Chytridiomycosis to European Amphibian Biodiversity (NERC standard grant NE/K014455/1 and NE/E006701/1; ANR-08-BDVA-002-03). M.C.F., J.S., C.W., P.G. were supported by the Leverhulme Trust (RPG-2014-273), M.C.F., A.C., C.W. were supported by the Morris Animal Foundation. J.V. was supported by the Bolyai János Research Grant of the Hunagrian Academy of Sciences (BO/00597/14). F.G. and D.G. were supported by the Conservation Leadership Programme Future Conservationist Award. C.S.A. was supported by Fondecyt (No. 1181758). M.C.F. and A.C. were supported by. Mohamed bin Zayed Species Conservation Fund Project (152510704). GMR held a doctoral scholarship (SFRH/BD/69194/2010) from Fundação para a Ciência e a Tecnologia. L.F.T., C.L., L.P.R. K.R.Z., T.Y.J., T.S.J. were supported by São Paulo Research Foundation (FAPESP #2016/25358-3), the National Counsel of Technological and Scientific Development (CNPq #300896/2016–6) and a Catalyzing New International Collaborations grant from the United States NSF (OISE-1159513). C.S.A. was supported by Fondecyt (No. 1181758). T.M.D. was supported by the Royal Geographical Society and the Royal Zoological Society of Scotland. B.W. was supported by the National Research Foundation of Korea (2015R1D1A1A01057282).Peer reviewedPublisher PD

Development and worldwide use of non-lethal, and minimal population-level impact, protocols for the isolation of amphibian chytrid fungi

© The Author(s) 2018.Parasitic chytrid fungi have emerged as a significant threat to amphibian species worldwide, necessitating the development of techniques to isolate these pathogens into culture for research purposes. However, early methods of isolating chytrids from their hosts relied on killing amphibians. We modified a pre-existing protocol for isolating chytrids from infected animals to use toe clips and biopsies from toe webbing rather than euthanizing hosts, and distributed the protocol to researchers as part of the BiodivERsA project RACE; here called the RML protocol. In tandem, we developed a lethal procedure for isolating chytrids from tadpole mouthparts. Reviewing a database of use a decade after their inception, we find that these methods have been applied across 5 continents, 23 countries and in 62 amphibian species. Isolation of chytrids by the non-lethal RML protocol occured in 18% of attempts with 207 fungal isolates and three species of chytrid being recovered. Isolation of chytrids from tadpoles occured in 43% of attempts with 334 fungal isolates of one species (Batrachochytrium dendrobatidis) being recovered. Together, these methods have resulted in a significant reduction and refinement of our use of threatened amphibian species and have improved our ability to work with this group of emerging pathogens.T.W.J.G., M.C.F., D.S.S., A.L., E.C., F.C.C., J.B., A.A.C., C.M., F.S., B.R.S., S.O., were supported through the Biodiversa project RACE: Risk Assessment of Chytridiomycosis to European Amphibian Biodiversity (NERC standard grant NE/K014455/1 and NE/E006701/1; ANR-08-BDVA-002-03). M.C.F., J.S., C.W., P.G. were supported by the Leverhulme Trust (RPG-2014-273), M.C.F., A.C., C.W. were supported by the Morris Animal Foundation. J.V. was supported by the Bolyai János Research Grant of the Hunagrian Academy of Sciences (BO/00597/14). F.G. and D.G. were supported by the Conservation Leadership Programme Future Conservationist Award. C.S.A. was supported by Fondecyt (No. 1181758). M.C.F. and A.C. were supported by. Mohamed bin Zayed Species Conservation Fund Project (152510704). GMR held a doctoral scholarship (SFRH/ BD/69194/2010) from Fundação para a Ciência e a Tecnologia. L.F.T., C.L., L.P.R. K.R.Z., T.Y.J., T.S.J. were supported by São Paulo Research Foundation (FAPESP #2016/25358-3), the National Counsel of Technological and Scientifc Development (CNPq #300896/2016–6) and a Catalyzing New International Collaborations grant from the United States NSF (OISE-1159513). C.S.A. was supported by Fondecyt (No. 1181758). T.M.D. was supported by the Royal Geographical Society and the Royal Zoological Society of Scotland. B.W. was supported by the National Research Foundation of Korea (2015R1D1A1A01057282).Peer Reviewe

Local phenotypic variation in amphibian-killing fungus predicts

Orientador: Luís Felipe de Toledo Ramos PereiraDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: Os anfíbios são os animais mais ameaçados do planeta, tendo como fatores mais impactantes a perda de habitat e a quitridiomicose. Esta doença em anuros é causada pelo fungo Batrachochytrium dendrobatidis (Bd), que já foi registrado em todos os continentes e no Brasil estende-se por toda a Mata Atlântica, e já foi encontrado no Cerrado e na Amazônia. Existem diversos fatores que podem influenciar a dinâmica de infecção na natureza, e como fatores intrínsecos ao Bd podemos citar a variação genotípica, morfológica, variação na virulência e taxas de crescimento. Com isso, o presente estudo teve como objetivos realizar a caracterização genotípica e fenotípica de cepas de Bd provenientes de um gradiente de elevação na Mata Atlântica, e verificar se existem associações entre o tamanho dos zoósporos e zoosporângios das cepas isoladas com dados de prevalência e intensidade de infecção e taxa de crescimento do Bd. Adicionalmente, foi analisado se as taxas de infecção aumentam conforme o aumento da elevação. Para tanto, foram isoladas e genotipadas cinco cepas de Bd. Foi realizado o diagnóstico e quantificação da doença, assim como a confecção de suas curvas de crescimento. Com base nos resultados foram desenvolvidos dois índices relacionados à variação em tamanho e dados de prevalência e intensidade de infecção. Todas as cepas isoladas pertencem à linhagem Bd-GPL2. Foi detectada variação fenotípica entre as cepas e associações entre tamanho das cepas com prevalência e intensidade de infecção, e não houve associação com as taxas de crescimento. A prevalência e intensidade de infecção não aumentaram com a altitude. Os índices de tamanho e infecção também foram associados. Com isso, a variação fenotípica pode ser considerada preditora da dinâmica de infecção do Bd na natureza. Isto poderá ser utilizado como eficiente ferramenta de baixo custo para estudos que busquem reconhecer áreas nas quais o fungo pode ser mais prevalente e apresentar maior intensidade de infecção. Estes fatores podem ser cruciais para determinar populações de anfíbios ameaçadasAbstract: Amphibians are the most threatened animals of the world. Habitat loss and chytridiomicosys are considered the main causes for their declines. Chytridiomycosis is a disease caused in anurans by the fungus Batrachochytrium dendrobatidis (Bd), detected worldwide. In Brazil it was registered all over the Atlantic rainforest and in some localities of the Cerrado and Amazonia. Several factors influence this disease dynamics, such as intrinsic factors related to Bd: different lineages, morphology, virulence, and growth rate. Given these factors, the present study aimed to genotype and analyze Bd strain¿s size from an elevational range, and verify if these factors were correlated to Bd size, prevalence, infection load, growth rate, and elevation. We isolated and genotyped five strains, and quantified growth rates. We developed two indexes related to Bd size, prevalence, and infection load. The five strains were Bd-GPL2. We found size variation and correlations between Bd size, prevalence, and infection load, but not with growth rate. Prevalence and infection load did not increase with elevation. The size and infection indexes were correlated. The phenotypic variation can be considered as a predictor to disease dynamics on environment. It can be used in other studies as a tool to efficiently (cheap and fast) identify areas where the fungus can develop faster and be more deleterious to amphibian populationsMestradoBiodiversidade AnimalMestra em Biologia Anima

Data from: Historical dynamics of Batrachochytrium dendrobatidis in Amazonia

The Amazon forest is known for its astonishing amphibian diversity, yet the potential distribution and underlying impacts of the most important amphibian pathogen is unknown for most of Amazonia. In this retrospective survey of preserved Leptodactylus frogs, collected over a 119 yr period, we used quantitative PCR to detect the fungal pathogen Batrachochytrium dendrobatidis (Bd) and performed spatial scan analyses to identify spatiotemporal clusters of Bd. We also quantified the potential effect of environmental factors on the likelihood of Bd occurrence and generated an updated suitability map for Bd in the Amazon that included our retrospective sampling. We detected Bd in lowland Amazon as early as 1935, in the state of Pará, Brazil, and we found low prevalence (∼ 3.8%) over time. We identified two statistically significant spatiotemporal clusters of Bd: a recent and narrow cluster in the Amazon River delta and a spatiotemporally broad cluster in the southern edge of Amazon and Brazilian savanna. Furthermore, we found an increase in Bd-positive samples in the southwestern Amazon after the 1990s, coinciding with reported amphibian declines in neighboring high elevation sites on Andean slopes of Peru. Spatial regressions indicated that higher human interference, higher precipitation, and lower temperatures were significant predictors of Bd occurrence. Environmental niche modeling predicted some narrow areas of suitable climates along the Amazon's periphery and generally low climatic suitability for Bd in the central Amazon; although, we found clusters of Bd-positive samples with unexpectedly high infection loads in areas of predicted low suitability. Our study indicates that accelerated human development may put Amazonian amphibians at risk from Bd introductions, and it highlights the potential need to monitor Bd dynamics near Amazonian port cities