New virus causing mass deaths of frogs

Common frog populations around the UK have declined by more than four-fifths because of a virus which causes their internal organs to haemorrhage.

Populations infected with ranavirus, which is thought to be relatively new to the UK, suffered an average 81 per cent decrease in adult frogs over a 12-year period, research from the Zoological Society of London (ZSL) found.

The study, using data collected from the public by the frog mortality project and charity Froglife, showed long-term declines in numbers because of the virus – as well as the sudden mass die-offs of frogs which the disease is known to cause.

But the research, published in the ZSL journal Animal Conservation, also found that some populations of frogs recovered from mass mortality events – suggesting that some frogs may be immune to the virus.