Farm nutrients cause frog deformities

BOULDER, Colo., Sept. 25 (UPI) -- A U.S. study suggested high levels of nutrients from farming and ranching activities increased infections that produced deformities in frogs.

University of Colorado-Boulder scientists found such nutrients fuel parasite infections that have caused highly publicized frog deformities in ponds and lakes across North America.

Researchers led by Assistant Professor Pieter Johnson determined the nutrients stimulate algae growth, which increases snail populations and the number of infectious parasites released by snails into ponds and lakes.

The parasites form cysts in the developing limbs of tadpoles causing missing limbs, extra limbs and other malformations, Johnson said.

"This is the first study to show that nutrient enrichment drives the abundance of these parasites, increasing levels of amphibian infection and subsequent malformations," said Johnson. "The research has implications for both worldwide amphibian declines and for a wide array of diseases potentially linked to nutrient pollution, including cholera, malaria, West Nile virus and diseases affecting coral reefs."

The study, which included scientists from Washington University, the University of Wisconsin, the Southern California Coastal Water Research Project and the University of Alaska appears in the online early edition of the Proceedings of the National Academy of Sciences.