PCR detection of ranavirus in adult anurans from the louisville zoological garden

Ranaviruses are known to cause mortality in a variety of anuran species and have the potential to significantly impact wild and captive frog populations. In this study, 16 captive frogs and toads from the Louisville Zoological Garden were examined for the presence of ranavirus; this group included 14 Cope's grey tree frogs (Hyla chrysoscelis), an American toad (Bufo americanus), and a southern toad (Bufo terrestris). All animals were wild caught and were evaluated via polymerase chain reaction (PCR), while animals that died were also assessed via histologic study to understand the role of ranaviral disease in these specimens. Of the animals that died, 82% were positive for ranavirus via PCR. Multiple swab samples collected over time from live tree frogs were positive for ranavirus via PCR. These findings reveal that ranaviral infection in captive adult anurans may occur without clinical signs or consistent histopathologic lesions.