Worldwide one third of all amphibian species are thought to be threatened with extinction and many others face severe population declines. Habitat loss is the main cause of declines worldwide, but there is growing concern surrounding the threats posed by infectious disease.
In the last decade amphibian diseases have received a great deal of scientific attention, and public awareness of what might otherwise be an esoteric issue is relatively high. This high profile is due to links to the phenomenon of amphibian global declines.
In the UK there are two pathogens of known significance to amphibian conservation are Ranavirus and Chytrid fungus. There are no proven cures for wild populations infected with either pathogen. The impacts of these diseases on population status in Britain are not yet well understood. There are however good reasons to adopt a precautionary approach to the potential spread of amphibian disease:
Guidelines for amphibian field workers have been produced to minimise the risk of transmission of amphibian disease. These guidelines are likely to be reviewed as more is learned about amphibian disease. In practice if disease is present at a particular site then amphibian migration between local ponds is likely to transfer disease anyway, making within-site control measures redundant. In general, though, the following precautions are advised:
Ranavirus seems to be found mainly in common frogs. It causes two forms of disease: skin ulcers and internal bleeding.Read more
The chytrid fungus Batrachochytrium dendrobatidis (Bd) is primarily a parasite of amphibians but may also be able to infect some birds and crustaceans which live in freshwater habitats.Read more