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 Frog
malformations
have been reported from 42 states. The broad geographic distribution of
these malformations warrants national attention. Scientists at the USGS
National Wildlife Health Center in Madison, Wisconsin, are studying this
problem in an effort to document its scope and to determine the causes
of the observed malformations.
Recent reports of amphibian declines and frog malformations have caused
great concern among the public and scientific communities. Multiple limbs,
missing limbs, and facial abnormalities are the striking hallmarks of
developmental malformations seen in these frogs. The broad geographic
distribution of these malformations, now reported from 42 states, and
the high percentage of malformations in some frog populations, up to 50%
malformed individuals in some locations, warrant national attention.
The USGS National Wildlife Health Center (NWHC) in Madison, WI, is collaborating
with state and federal agencies to conduct integrated studies to determine
the causes of these malformations. USGS scientists have modified and expanded
their diagnostic capabilities and field investigation methods to accommodate
the unique life history and habitat of amphibians. These new capabilities
are particularly important in determining whether infectious agents play
a role in causing the observed malformations. This year, NWHC expanded
its research to include examination and diagnostic testing of tadpoles
to help pinpoint when malformations begin.
Detailed examination of northern leopard frogs by the USGS has led to
more complete characterization of malformations in this species. It was
found that the developmental errors that lead to malformations occur in
the developing tadpoles. Such baseline information is essential before
any cause can be determined.
Several hypotheses are being considered to explain the causes of malformations
including chemical contamination, infection, exposure to the sun's ultraviolet
rays, or physical trauma. Sorting out the possibilities is difficult but
essential. The resulting information will contribute to a more complete
picture of the types of agents and environmental insults that cause amphibian
malformations.
The USGS Northern Prairie Wildlife Research Center in Jamestown, ND, has
established the North American
Reporting Center for Amphibian Malformations (NARCAM). This web site
contains information on the occurrence of amphibian malformations including
maps showing locations of observed malformed frogs. The site also enables
scientists and the general public to report any findings of frog abnormalities
either through the web site or through a toll free phone number (800-238-9801).
These observations further enhance the research into this phenomenon.
By studying malformations in frogs, USGS scientists at NWHC are helping
to answer one question within the greater mystery of amphibian decline.
For more information
about this topic, contact: Dr.
Carol Meteyer, Phone: (608) 270-2462, or Dr.
David Green, Phone: (608) 270-2482, USGS, National Wildlife Health
Center.
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