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Abstract The amphibian chytrid fungusBatrachochytrium dendrobatidis(Bd) is a cosmopolitan pathogen with numerous distinct lineages. The global panzootic lineage (Bd-GPL) is the most widespread and virulent lineage and is responsible for many recorded amphibian declines. Mapping the extent ofBd-GPL and other more established lineages is important for predicting disease dynamics in amphibian communities. Ecuador is the most biodiverse country per unit area for amphibian taxa and, thus, a priority for studies on genotypic diversity ofBd. In this study, we tested skin swab samples collected from 464 individual amphibians across coastal, Andean montane, and Amazonian forests, for the presence of twoBdlineages known to be present in South America: the globally-distributedBd-GPL and the Brazilian-endemicBd-Asia2/Brazil lineage. By using a discriminatory qPCR SNP assay, we found widespread prevalence ofBd-GPL in Ecuador in diverse host taxa. Genotyping efficiency was 36% in this study, meaning that one in every three swabs that tested positive forBdin infection assays were successfully genotyped. Through this study, we provide further support for the presence of a singleBdlineage in this neotropical biodiversity hotspot.
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This content will become publicly available on December 12, 2025
Detection of the Batrachochytrium dendrobatidis global panzootic lineage in Ecuadorian anurans of the Amazonian lowlands
Considerable attention has been directed to studying the infection dynamics of the fungal pathogenBatrachochytrium dendrobatidis(Bd) affecting amphibians in the high elevations of the Neotropics. However, lowland forests of the same realm remain comparatively understudied in this context. Herein, we attempt to bridge this gap by measuring the prevalence ofBdvia quantitative polymerase chain reaction (qPCR) in several anuran taxa inhabiting the Amazonian lowlands in the northeast of Ecuador. To this end, we sampled 207 anurans from 10 different families, 25 different genera, and 55 distinct host species originally collected in 2008. Taxonomy (at the family level), morphology (i.e. weight and snout-vent length), and life-long aquatic dependency of hosts (i.e. aquatic index) were also compiled to serve as potential predictors ofBdinfection status. Our findings revealed a relatively highBdprevalence of 58%, with 88% of sampled anuran families testing positive for the fungus at varying proportions. Model selection involving fitting and testing several different linear models, including mixed linear models, revealed a significant negative relationship between host weight andBdinfection status (p < 0.01). However, no significant associations were observed between taxonomy, aquatic dependency, snout-vent length, andBdinfections. In addition, we only detected the global panzootic lineage ofBd(Bd-GPL) and not theBd-Asia-2/Bd-Brazil lineage via qPCR single nucleotide polymorphism (SNP) genotyping. Our findings contribute to the understanding ofBddynamics in the Neotropical lowlands and emphasize the need for future research on the ecological factors influencingBdin the Amazon and their implications for amphibian conservation.
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- Award ID(s):
- 2041629
- PAR ID:
- 10620925
- Publisher / Repository:
- Diseases of Aquatic Organisms
- Date Published:
- Journal Name:
- Diseases of Aquatic Organisms
- Volume:
- 160
- ISSN:
- 0177-5103
- Page Range / eLocation ID:
- 115 to 125
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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