Frogs are more vulnerable to an infectious disease caused by Ranavirus when temperatures rise. Photo by Lewis Campbell/ZSL

May 10 (UPI) -- Earth's warming climate is encouraging the spread of a virus causing a deadly epidemic among common frogs, Rana temporaria.

When a team of researchers in England compared the records of mass-mortality events linked to Ranavirus with climate patterns, they found rising temperatures were associated with an increased risk of a viral outbreak.


If temperatures continue to rise, scientists expect Ranavirus outbreaks to become more severe and occur more frequently.

In addition to analyzing weather and frog mortality data compiled by the Met Office and Froglife's Frog Mortality Project, scientists also studied cell cultures and live models in the lab. Their tests confirmed warmer temperatures increased the likelihood of Ranavirus triggering an outbreak of the fatal disease.

The latest findings, published this week in the journal Global Change Biology, explain why biologists have long observed the most severe disease outbreaks during the summer's hottest months.

As global warming continues, the disease, which has been mostly observed in England, could make its way into other parts of the United Kingdom. Outbreaks could also become more common in the spring and fall. Large spring outbreaks could kill tadpoles and severely depress frog populations.

Previous studies have suggested amphibians, especially frogs, salamanders and newts, are especially vulnerable to the ill effects of climate change.

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"Climate change isn't something that's just happening in faraway places -- it's something real and present that's already had hard-to-predict impacts on wildlife in our own back gardens here in the U.K.," Stephen Price, researcher with University College London and the Zoological Society of London, said in a news release.

"A number of scientists have already alluded to the fact that climate change could increase the spread of disease, but this is one of the first studies that provides strong evidence of the impact of climate change on wildlife disease, and helps to explain how it may facilitate the spread of Ranavirus across the U.K.," Price said.

Price and his research partners suggest the addition of log piles, vegetation and other types of shady structure to frog habitat could help the amphibians stay cool and avoid infection.

"Many studies in amphibian disease cannot do much beyond saying 'we have a problem," said Trenton Garner, researcher at ZSL's Institute of Zoology. "This research offers a number of options for mitigation; however, this is only a short-term solution of course -- if we don't eventually slow and reverse human-driven climate change, we unfortunately can only expect things to get worse for our amphibians."