Multi-tool diagnosis of an outbreak of ranavirosis in amphibian tadpoles in the Canadian boreal forest

A definitive diagnosis of ranavirosis was established in wild amphibian tadpoles from Wood Buffalo National Park, Canada, using a multi-tool approach combining histopathology, immunohistochemistry (IHC), in situ hybridization (ISH), and quantitative PCR. The outbreak affected wood frog (Rana sylvatica) and boreal chorus frog (Pseudacris maculata) tadpoles, while sympatric Canadian toad (Bufo hemiophrys) tadpoles showed no mortality, suggesting species-specific susceptibility. Key histopathologic lesions included necrosis of the skin, oral mucosa, renal tissues, and branchial epithelium, with skeletal and connective tissues in budding limbs showing intense ranavirus presence even without obvious necrosis. The study highlights the effectiveness of integrating multiple diagnostic techniques to unravel pathogenesis in wild amphibians, providing critical insights into disease emergence linked to developmental stages.

Forzán, M., Bienentreu, J., Schock, D., & Lesbarrères, D. (2019). Multi-tool diagnosis of an outbreak of ranavirosis in amphibian tadpoles in the Canadian boreal forest. Diseases of Aquatic Organisms, 135(1), 33–41. https://doi.org/10.3354/dao03369