Frogs are going extinct. So are toads, salamanders, newts, and the intriguingly unusual caecilians. In fact, the World Conservation Union (IUCN) estimates that at least one-third of known amphibian species are threatened with extinction. While the major culprit has historically been habitat loss and degradation, many of the declines and extinctions previously referred to as "enigmatic" are now being attributed to the rapidly dispersing infectious disease chytridiomycosis ("chytrid"). This fungus is causing population and species extinctions at an alarming rate. Can you imagine if we were about to lose one-third of the world's mammals?

Amphibian chytrid fungus is not the only cause of amphibian decline, but is a likely explanation for unexplained declines in high-altitude, protected regions and may hasten the collapse of populations weakened by other threats such as habitat destruction, climate change, and water and air pollution.

 

 Photo courtesy of Bill Konstant

The disease known as chytridiomycosis, results when a chytridiomycete fungus called Batrachochytrium dendrobatidis ("chytrid") attacks keratin in the skin tissue of amphibians. Many researchers believe that this infectious fungus inhibits the frog’s ability to respire and osmoregulate, eventually killing the frog. Amphibian chytrid fungus has been implicated in amphibian declines in the Americas, Caribbean, and Australia and its range continues to grow.

Amphibian chytrid is not the only cause of amphibian decline, but is a likely explanation for unexplained declines in high-altitude, protected regions and may hasten the collapse of populations weakened by other threats such as habitat destruction, climate change, and water and air pollution.

 

 
Photo courtesy of Allan Pessier, DVM