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

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 of Bd in 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 for Bd DNA 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 of Bd ( Bd- GPL) in the Ecuadorian Amazon. The overall infection prevalence of Bd was determined to be 58%, which is a relatively high prevalence rate of Bd reported 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 of Bd infections (p < 0.05). However, no significant associations were observed between host taxonomy, aquatic dependency, or snout-vent length and Bd prevalence. Our findings contribute to the understanding of Bd dynamics in the Neotropical lowlands and emphasize the need for future research on the ecological factors influencing Bd in the Amazon and their implications for amphibian conservation.