Prevalence of the pathogenic chytrid fungus, <i>Batrachochytrium dendrobatidis</i>, in an endangered population of northern leopard frogs, <i>Rana pipiens</i>

<br><b>Background</b> <br> Emerging infectious diseases threaten naïve host populations with extinction. Chytridiomycosis, an emerging infectious disease of amphibians, is caused by the pathogenic fungus <i>Batrachochytrium dendrobatidis</i> (<i>Bd</i>) and has been linked to global declines in amphibians. <br> <b>Results</b> <br> We monitored the prevalence of <i>Bd</i> for four years in the Northern leopard frog, <i>Rana pipiens</i>, which is critically imperiled in British Columbia (BC), Canada. The prevalence of <i>Bd</i> initially increased and then remained constant over the last three years of the study. Young of the year emerging from breeding ponds in summer were rarely infected with <i>Bd</i>. Some individuals cleared their <i>Bd</i> infections and the return rate between infected and uninfected individuals was not significantly different. <br> <b>Conclusions</b> <br> The BC population of <i>R. pipiens</i> appears to have evolved a level of resistance that allows it to co-exist with <i>Bd</i>. However, this small population of <i>R. pipiens</i> remains vulnerable to extinction.