14 DAY TRIAL // A new research published in the Zoological Society of London's (ZSL) journal Animal Conservation, shows that the common British frog (Rana temporaria) populations are dramatically decreasing because of Ranavirus infections.
This research gathered data from the public by the Frog Mortality Project and Froglife, and ZSL scientists found out after analysis that, on average, during a 12 year period, infected frog populations had a 81% decline rate in adult frogs.
Lead author of the study, Dr Amber Teacher from ZSL, said that the “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 minimize the serious threat that it poses to our native amphibians.”
The researchers found out that despite a certain number of populations suffering from this infection every year, there were some populations that recovered rather well from mass-mortality events.
This phenomenon might be linked to some form of immunity of certain frogs to the ranaviral infection.
Lucy Benyon from Froglife says that “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.”
“However, we still need regular information from the public on what is happening in their ponds to continue this essential research,” she adds.
Ranaviruses are part of the Iridoviridae family, a group of large double stranded DNA viruses that affect cold-blooded vertebrates.
Ever since the 1960s, Ranavirus infections were known in amphibians, but they were not associated with disease and death until 20 years later, because of large-scale disease and mortality events.
In the 80s and 90s, the disease was especially related to the southeast of England, but in more recent years, the virus has shown up in Lancashire, Yorkshire and also along the south coast.
Co-author Dr Trent Garner from ZSL, said that “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,” he added.