Killer disease decimates UK frog populations

(PhysOrg.com) -- Common frog (Rana temporaria) populations across the UK are suffering dramatic population crashes due to infection from the emerging disease Ranavirus, reveals research published in the Zoological Society of London's (ZSL) journal Animal Conservation.

Using data collected from the public by the Frog Mortality Project and Froglife, scientists from ZSL found that, on average, infected frog populations experienced an 81 per cent decline in adult frogs over a 12 year period.

"Our findings show that Ranavirus not only causes one-off mass-mortality events, but is also responsible for long-term population declines. We need to understand more about this virus if we are to minimise the serious threat that it poses to our native amphibians," says Dr Amber Teacher, lead author from ZSL.

Despite a number of populations suffering from infection year-on-year, other populations bounced-back from mass-mortality events. This suggests that some frogs may have some form of immunity to ranaviral infection.

"The discovery of persistent populations in the face of disease emergence is very encouraging and offers hope for the long-term future of this species" says Lucy Benyon, Froglife. "However, we still need regular information from the public on what is happening in their ponds to continue this essential research."

In the 80s and 90s, the disease was particularly associated with the southeast of England. In recent years new 'pockets' of diseases have turned up in Lancashire, Yorkshire and along the south coast.

"It is very difficult to treat wildlife diseases and so the mystery that we desperately need to solve is how the disease spreads. Understanding more about the ecology of the disease will allow us to offer advice to the public on how to limit the spread of infection, which could also prevent the movement of other frog diseases in the future," says co-author Dr Trent Garner from ZSL.