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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 March 1, 2027
Host Genus and Habitat Use Shape the Distribution of Batrachochytrium dendrobatidis Lineages in a Hyper‐Diverse Tropical Amphibian Community
ABSTRACT Pathogens often exploit ecological and evolutionary opportunities created by anthropogenic change, with profound consequences for host communities. In Brazil's Atlantic Forest, the amphibian chytrid fungusBatrachochytrium dendrobatidis(Bd) exemplifies this dynamic, with two co‐occurring lineages: the enzootic Bd‐Brazil lineage and the invasive Global Panzootic Lineage (Bd‐GPL), implicated in historical amphibian declines and Bd hybridization events. To investigate how host taxonomy and habitat use influence Bd lineage distribution, we sampled 3836 amphibians representing 42 species across paired aquatic and terrestrial transects over a two‐year period. We successfully genotypedn = 252 out of 777 Bd‐positive samples using nuclear and mitochondrial SNP assays to differentiate between Bd‐GPL, Bd‐Brazil, hybrids, and coinfections. Our results reveal that Bd lineage distribution is nonrandomly associated with host genus and habitat type. Stream‐dwelling frogs, particularly those in the genusHylodes, had higher rates of coinfection with Bd‐GPL and Bd‐Brazil than most other genera. This pattern may reflect their lifelong association with streams, which might increase their exposure to zoospores from multiple Bd lineages. In contrast, terrestrial transects were dominated by single‐lineage Bd‐GPL infections, even when accounting for differences in amphibian species composition and host genus among transect types. These findings suggest that aquatic habitats could serve as refugia for Bd‐Brazil, while Bd‐GPL may exhibit more desiccation tolerance. Methodological limitations of this study, including biases towards successfully genotyping high‐load infections and limited genomic resolution, underscore the need for more high‐resolution sequencing approaches to fully understand pathogen dynamics in the Atlantic Forest.
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- Award ID(s):
- 2120084
- PAR ID:
- 10709729
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Ecology and Evolution
- Volume:
- 16
- Issue:
- 3
- ISSN:
- 2045-7758
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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