A fungus that has killed vast numbers of amphibians in South America and Australia is now known to kill threatened or endangered amphibian species in Arizona and Colorado. Wis. The boreal toad is listed as endangered by Colorado and New Mexico, although no known populations exist in New Mexico now. These toads were once common around lakes, ponds and streams in the mountains of Colorado, northern New Mexico and southern Wyoming, but the population numbers dropped precipitously in the last 20 years. Sick and dying toads in the Colorado population were first discovered in May 1999 by Colorado Division of Wildlife researchers, who have been intensively studying the animals for the last five years. Since May, dead toads have been found every month at the site, which is on private land west of Denver.
Scientists stain the frog skin to reveal the fungus under a microscope.
USGS researchers said they have identified chytrid fungus in many of the dead and living toads they examined from the site in 1999. Live toads show few clinical signs of the disease, but some may appear weak, lethargic and reluctant to flee at the approach of humans. Green, microscopically examined many of the dead toads and identified myriads of minute chytrid fungi in the skin of the abdomen and toes of the toads. His microscopic identification of this fungus is being confirmed in collaborative work by Dr. Joyce Longcore, a world-renowned chytrid expert at the University of Maine. In addition, USGS researchers will continue to work closely with researchers from the Colorado Division of Wildlife to monitor further die-offs.