A British-led study suggests the introduction of the North American bullfrog into many nations might be causing the spread of a deadly fungus.
Biologists around the world have noted a dramatic decline in the number of amphibians, placing about one-third of all species at risk of extinction. Scientists believe the chytrid fungus might be responsible for the amphibian deaths.
The fungus clings to the skins of amphibians, causing a disease called chytridiomycosis, although the exact cause of death is still undetermined, the BBC reported Wednesday.
Scientists writing in the journal Biology Letters say they found non-native North American bullfrogs carry the chytrid fungus and might act as a vector. Those bullfrogs -- some reaching 8 inches in length and 1 pound in weight -- have been introduced into many nations to be farmed for frog legs, kept as pets or for other reasons.
The nations involved are numerous, and include Brazil, Uruguay, France, Italy, Canada and the United Kingdom.
"We have shown that introduced bullfrogs consistently carry the fungus in the wild," Trent Garner, lead author of the paper and a wildlife epidemiologist from the Zoological Society of London, told the BBC.
Copyright 2006 by United Press International
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