Amphibians are experiencing a global collapse and chytridiomycosis, a disease caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is thought to be a major factor in these declines. Beginning in the 1970s, Bd-related declines or extinction of at least 200 species of amphibians have since been recorded in pristine habitats in Australia, Europe, Africa, and the Americas. Interestingly, none are recorded in Asia. Bd may be responsible for the greatest disease-related loss of biodiversity in recorded history and Bd-related declines have been identified as the first wave of a sixth mass extinction. The emergence and dynamics of Bd is not yet fully understood, especially in Asia. In Indonesia, Bd has been shown to be present among amphibians on Java and Sulawesi. Recent studies have revealed complexities within the phylogeny of Bd. The Bd “Global Panzootic Lineage” (GPL) is a geographically widespread lineage of Bd that is associated with Bd-related epizootics. Studies in China, Korea, and Brazil reported divergent Bd lineages, which suggests long-term endemism of Bd and Asian amphibians. I used an integrative approach which includes field surveys, laboratory infection trials, Next Generation Sequencing and sampling of museum specimens to determine whether the GPL Bd strain affects Javan frog species.
Results/Conclusions
Our field survey of 15 different species of frogs in West Java showed an 11% prevalence in the population, with no significant difference in prevalence between species. Distance to water bodies is a significant predictor of Bd occurrence among wild frogs, with the highest occurrence of Bd being close to lakes and streams. Our laboratory infection trial showed Bd resistance of all 4 of the frog species tested (Rhacophorus reinwardtii, Hylarana chalconota, Microhyla achatina, and Leptobrachium hasseltii). Inoculated individuals were able to shed Bd infection within 3 weeks of the 10-week trial, and no statistical difference in survivorship was observed between the experimental and control group. Our historical sampling from the Museum of Zoology in Bogor, Indonesia showed a relatively recent increase in Bd prevalence. The earliest positive we found for Bd was in the 1960’s and Bd prevalence only significantly increased in prevalence starting from the 1990’s to the 2000’s.