What is ranavirosis?

Ranavirosis is a disease caused by ranavirus, a group of viruses that infect amphibians, reptiles and fish. In the UK, ranavirosis is best known for affecting common frogs, although common toads, smooth newts and other species can also become infected.

The virus is thought to have been introduced to the UK through the international wildlife trade, most likely via imported North American bullfrogs and ornamental fish. Once established, it can spread between ponds via infected animals, contaminated water, equipment, or human activities.

Signs of ranavirosis

Not all infected amphibians show obvious signs of disease, but affected animals may display:

• Redness or haemorrhaging, particularly on the legs or underside.

• Skin ulcers or open sores.

• Swelling (oedema).

• Lethargy or unusual behaviour.

• Dead or dying frogs around ponds, particularly during the spring and summer.

Image from: Ranavirus Disease - Garden Wildlife Health