Distribution of the Amphibian Chytrid Fungu, Batrachochytrium Dendrdobatidis, in Cameroon

The precipitous decline of amphibian species worldwide has been attributed primarily to the infectious disease, chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). One of the earliest cases of Bd infection was found in a specimen of Xenopus fraseri collected in Cameroon in 1933. However, little is known about the distribution of Bd across much of Equatorial Africa, including biodiversity-rich montane regions such as the Gulf of Guinea. The specific objectives of this project are to: (1) map the distribution of Bd in amphibian communities at five ecologically distinct areas in Cameroon that span an important part of the Gulf of Guinea biodiversity hotspot; (2) determine if key environmental variables can be used to predict Bd presence, and (3) produce spatial maps that model the likely distribution of present and future Bd dispersal throughout the country. Approximately 400 amphibian skin swabs were screened for presence of Bd using quantitative polymerase chain reaction (qPCR). The spatial distribution of Bd was modeled using the ecological niche modeling approach implemented in the program MaxEnt. Environmental variables associated with precipitation, temperature, and proximity to human settlements exhibit positive relationships with Bdpresence. By determining the environmental predictors of Bd we have improved our understanding of its current and potential future distribution across the region, identified communities vulnerable to future infection and targeted areas that may represent reservoirs of resistance. This project has generated quantitative data on the prevalence of this devastating disease in an area long recognized for harboring high levels of amphibian endemicity as well as provided novel information on the current status of Bd dispersal and potential for its future spread.