Use of polyclonal antibodies, electron microscopy and histopathology to detect iridovirus-like particles in bullfrogs

Abstract

Iridoviruses of the Ranavirus genus have been implicated in the decline in amphibians worldwide, capable of affecting animals b o t h i n t h e w i l d a n d i n c a p t i v i t y . This study a i m e d to detect iridovirus-like particles from three frog farms in southeastern Brazil using primary polyclonal antibodies, transmission electron microscopy (TEM) and histologic findings. The target organs were liver and kidneys. Sixty adults and sixty tadpoles of bullfrogs (Lithobates catesbeianus) were used in the study. TEM revealed the presence of iridovirus-like particles in hepatic tissue using the negative staining technique. Positive results were also observed by immunoelectron microscopy and immunocytochemistry (ICC). The histological analysis o f t h e s a m p l e s s h o w e d liver hemorrhage and corpuscles inclusion in hepatocytes as well as glomerulotubular degeneration and necrosis in the kidneys. The methods used in this study were highly efficient to detect the presence of iridovirus-like particles and possible infection of ranavirus.