Detection of Herpesvirus Infection (RaHV-1) in amphibians from commercial, experimental, and recreational breeding in São Paulo State, Brazil

Frog farming represents an alternative animal production system with significant economic potential, especially in Brazil, recognized as one of the largest global producers of captive-bred frogs. However, inadequate management and environmental stressors may lead to outbreaks of infectious diseases, including those caused by herpesviruses (RaHV-1), posing severe health risks to animals and threatening production viability. This study aimed to detect the presence of herpesvirus in amphibians from commercial, experimental, and recreational facilities in São Paulo State, Brazil. Skin fragments and internal organs from 49 amphibians were analyzed using transmission electron microscopy and histopathological techniques. Findings revealed that 23 animals were positive for RaHV-1, showing pleomorphic viral particles, some enveloped, with diameters between 120 and 200 nm in both skin and organ fragments. Histopathological examinations also revealed intranuclear structures in various organs suggestive of RaHV-1. These findings indicate the circulation of RaHV-1 in Brazilian frog farms, highlighting the importance of further studies to better understand disease pathology and mitigate its impact on production.