[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2012/06/EW-07-13-12-Frogs-Cytridomycosis.mp3|titles=EW 07-13-12 Frogs (Cytridomycosis)]
From the Andes to the Pyrenees, a fungal disease has been blamed for the death of frogs and salamanders. A number of species native to Australia and South America are now extinct and massive declines have been recorded in North America and Europe.
The culprit? Cytridiomycosis. This emerging infectious disease, first identified in 1998, is spread through a fungal pathogen, with animals that breed in permanent water bodies suffering the most serious declines.
San Francisco State University biologist Vance Vredenburg explains how infected animals are impacted…
“Many animals succumb and die without any outward signs. It actually causes what’s called hyper-keratosis – an extreme growth in the skin – and amphibians many times end up with skin that is 40 times thicker than it would be normally.”
International trade is driving the spread of the deadly disease. Some animals, such as American bullfrogs, are silent carriers. In Central America, millions of bullfrogs are raised in factory farms. The high-protein meat is sold ‘fresh killed’ at international markets. Escaped animals have been implicated in transferring the disease to native species that lack resistance.
“You know I can’t sound alarmist enough – it’s the worst case in recorded history of a single pathogen affecting vertebrates. It may be responsible for the disappearance of up to 300 species of amphibians, and that’s incredibly rare for pathogens.”
Scientists are working to understand the mechanisms that lead to chytridiomycosis outbreaks. Current research is also exploring how to inoculate susceptible species with beneficial bacteria, to boost survivorship in populations already suffering from infections.
Photo, taken on March 12, 2011, courtesy of Frank Bonilla via Flickr.