Discovery of a novel alveolate pathogen affecting southern leopard frogs in Georgia: Description of the disease and host effects

摘要: In April of 2006, we observed southern leopard frog (Rana sphenocephala) tadpoles in a pond northeast Georgia that were dying from an unknown pathogen. Examination affected specimens, as well PCR characterization, revealed all infected with novel alveolate pathogen closely related to freshwater and marine eukaryotic organisms and, lesser degree, members the genus Perkinsus. This has been documented numerous mortality events anuran United States, although it not yet named nor clearly described. We subsequently conducted systematic survey this four other ponds same area document extent describe nature infections tadpoles. Of 87 live examined, 25% pathogen, based on visual inspection tadpole liver tissue. Affected frequently had enlarged abdomens, swam erratically, could be captured by hand. All organs infiltrated but typically than kidneys, which often hundreds thousands spherical, 6-μm organisms. Infected tended weigh more noninfected ones, likely due massive organ swelling coincided infections. did differ developmental stage Infection prevalence varied widely among ponds, one pond, witnessed rapid die-off R. spenocephala during our surveys, find metamorphic frogs. The vast number seen specimens suggests tremendous transmission potential, therefore deserves further monitoring study.