Elevated prevalence of the global panzootic chytrid strain in Ecuadorian anurans of the Amazonian lowlands

Abstract

Considerable attention has been directed to studying the infection dynamics of the fungal pathogen,Batrachochytrium dendrobatidis(Bd), affecting amphibians in the high elevations of the Neotropics. Lowland forests of the same realm, on the other hand, remain relatively understudied in this context. Herein, an attempt to bridge this gap was made by investigating the occurrence ofBdin several anuran taxa inhabiting the Amazonian lowlands in the northeast of Ecuador. To this end, 207 anurans belonging to 10 different families, 25 different genera, and 55 distinct host species were sampled forBdDNA in 2008. Data on the taxonomy, morphology (i.e., weight and snout-vent length), and life-long aquatic dependency of hosts (i.e., aquatic index) were also collated to serve as potential predictors of infection prevalence. Genotyping via quantitative PCR revealed the presence of the global panzootic lineage ofBd(Bd-GPL) in the Ecuadorian Amazon. The overall infection prevalence ofBdwas determined to be 58%, which is a relatively high prevalence rate ofBdreported for any amphibian population from the lowlands of the Neotropics to date. A total of 88% of sampled anuran families tested positive for the infection at varying proportions. A logistic regression analysis showed a significant negative relationship between host weight and the proportion ofBdinfections (p < 0.05). However, no significant associations were observed between host taxonomy, aquatic dependency, or snout-vent length andBdprevalence. 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.