Frogs spreading fungal infection

The Pacific chorus frog, a common amphibian found in the west coast of North America, may be spreading the deadly fungal infection that is killing other amphibian species, a new study has suggested.

Researchers at San Francisco State University found that the tiny frogs not only survive an epidemic of the disease, called chytridiomycosis, they were also able to survive while carrying high loads of the fungus responsible for the disease.

Chytridiomycosis is blamed for the extinctions in more than 200 amphibian species around the world, including the yellow-legged frogs — in Sixty Lake Basin in the Sierra Nevada Mountains. The water-dwelling fungus attacks an amphibian’s skin, disrupting the animal’s ability to transport electrolytes — charged ions such as sodium — and ultimately causing cardiac arrest and death, LiveScience reported.

Pacific chorus frogs are common along the Pacific coast from Baja California to British Columbia, and known for their distinctive “ribbit” calls.

According to the researchers, skin swabs taken from the chorus frogs living in the basin where the epidemic occurred over the past decade confirmed the chorus frogs were indeed infected with the chytrid fungus, called Batrachochytrium dendrobatidis or Bd. The chorus frogs are not the first to be identified as Bd carriers. The American bullfrog, Rana catesbeiana, and the African clawed frog, Xenopus laevis, also appear able to live with Bd infections, the researchers said.

However, the high levels of the fungus in the chorus frog indicate it might make a more efficient carrier.