Amphibian and Reptile Diseases

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diseased frog

Diseased frogs showing lethargy



Northern Leopard Frogs (Lithobates pipiens) from McLeod County, MN showing lethargy typical of diseased frogs.

Photo by MNDNR, Laurinda Brown.

Reddening of skin along the ventral surface of the body, legs, and feet of frogs is often associated with disease. In this case, this Northern Leopard Frog tested positive for chytridiomycosis.

Photo by MNDNR, Laurinda Brown.

A number of diseases and malformations are affecting both reptiles (turtles, snakes and lizards) and amphibians (frogs, toads, and salamanders) around the world and in some cases in Minnesota. Many of the species involved in die-offs are fairly common and widespread in the United States, but some are either declining in number or are already threatened or endangered. Many of the symptoms for these diseases are “non-specific” that is, the symptoms for various diseases can look similar and in some cases, only dead animals may be found. For these reasons it is not possible to diagnose these diseases with the naked eye and laboratory testing is required. There is some basic information about some of the more common diseases below with links to additional information. In addition, large die-offs during winter ("winterkill") or early spring are a natural phenomenon affecting fishes, turtles and/or frogs, and is not necessarily associated with disease.

Many wildlife diseases are tracked through the National Wildlife Health Lab (NWHL) and the Lab currently has an Amphibian Research and Monitoring Initiative. Much of the information below is from NWHL and Amphibian Ark.


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Amphibian Malformations


Iridovirus (Ranavirus)


Snake Fungal Disease

Additional Resources

AmphibiaWeb: Information on amphibian biology and conservation. [web application]. Berkeley, California.

Minnesota Herpetological Society

Partners in Amphibian and Reptile Conservation