Ranaviruses: Overview and Host Impact
Ranaviruses are enveloped, double-stranded DNA viruses belonging to the family Iridoviridae. They are globally distributed and possess a remarkably broad host range, infecting multiple animal classes including amphibians, reptiles, and fish. Transmission occurs via direct contact, environmental contamination, or cannibalism (ingestion of infected animals).
Amphibians
Ranaviruses are increasingly detected in amphibians and are associated with systemic disease and mass mortality. Two clinical forms are recognized:
Haemorrhagic form: marked by erythema (especially on the abdomen and upper legs), ulceration of the toes, and increased bleeding tendency.
Cutaneous form: may present with skin lesions.
Some animals succumb rapidly without prior signs of illness, while others may act as inapparent carriers.
Chelonians (Turtles and Tortoises)
In chelonians, ranaviruses are linked to:
Stomatitis
Hepatitis
Rhinitis and pneumonia
Sudden death
Detection in live animals is typically performed using oral swabs or blood samples. In deceased animals, liver, tongue, and skin are preferred tissues for virus identification.
Lizards
Ranavirus infection in lizards is associated with:
Skin lesions
Stomatitis
Granulomatous inflammation
Hepatitis
Mass mortality
Diagnostic sampling includes oral swabs or skin in live animals, and liver, tongue, and skin in post-mortem cases.
Snakes
In snakes, ranaviruses have been observed to cause:
Granulomatous lesions in the oral cavity and liver
Stomatitis and hepatic changes
Detection is carried out using oral swabs or liver samples.
Fish
Ranaviruses also affect fish, with presentations ranging from clinically inapparent infections to systemic disease with mass mortality.
