Ranavirus

Ranavirus is a genus of large double‑stranded DNA viruses in the family Iridoviridae that infect ectothermic vertebrates, most notably amphibians, but also some fish and reptiles. These viruses are environmentally persistent in aquatic settings and can spread through contaminated water, direct contact between animals, shared equipment, or movement of infected individuals. Ranavirus outbreaks have caused significant mortality in wild and captive populations and are a concern for biodiversity and wildlife health.

Virology and taxonomy are characterized by enveloped, icosahedral virions with a linear double-stranded DNA genome that typically spans roughly 100 to 200 kilobases and encodes many genes. Replication occurs in the cytoplasm, where viral factories are formed. The genus includes several well‑documented representatives, such as Frog virus 3 (FV3)–like ranaviruses, which have been used in research and linked to disease outbreaks in amphibians.

Clinical disease in amphibians often involves a systemic infection with high mortality, particularly in larvae and juveniles. Affected animals may display lethargy, edema, hemorrhagic lesions in internal organs, skin ulcers, and rapid decline. Infections in fish and reptiles present with variable signs depending on species and tissue tropism. Diagnosis generally relies on molecular methods such as PCR targeting conserved viral genes, supported by virus isolation in cell culture and histopathology showing characteristic cytoplasmic viral inclusions.

Management focuses on biosecurity and prevention. There is no widely available curative treatment; control measures emphasize quarantine and testing of animals, decontamination of equipment and facilities, and prevention of movement of potentially infected individuals between populations.