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Chytrid News

During this year (2006), chytridiomycosis, sometimes referred to as "chytrid fungus" or "Bd" (Batrachochytrium dendrobatidis), was found in Eastern Newts (Notophthalmus viridescens) from two well-known commercial vendors of amphibians. In two shipments received from a vendor in the southern portion of the United States, mortality from the disease exceeded 60% of over 400 animals. In another shipment from the East Coast, Eastern Newts tested positive for the disease but no mortality was experienced in over a month of quarantine. Although Bd is very widespread, this may be the first report of infection in a commercial source. The purpose of this note is to alert scientific users to the possibility of the fungus in shipments from these and other suppliers of amphibians. Many species of amphibians in addition to Eastern Newts are susceptible to the disease, so the concern extends beyond a single species. Bd infects epidermis where it is saprophytic on keratin and may interfere with respiration, gas exchange, and uptake of chemicals. Infections are frequently lethal. Studies indicate that Bd may be more deleterious to adult and juvenile amphibians than to larvae, but larvae may carry the disease only to have it expressed after metamorphosis. Amphibians collected and shipped as eggs or embryos may have lower or no incidence of the disease because keratin has not yet formed in these life stages.
To reduce the potential for problems associated with Bd, we recommend that all shipments of wild-caught larvae, juvenile and adult amphibians be inspected for the fungus. This can be done by having someone experienced with the disease examine epidermal scrapings microscopically or histologically. A more definitive method of determining the presence of Bd is to collect epidermal swabs and have them genetically tested via polymerase chain reaction (PCR). Quarantining animals for two or more weeks prior to placement in study may aid in diagnosis but will not guarantee absence of the disease. Unusually high sloughing of skin seems to be a sign of infection in newts.
Chytridiomycosis may be treated with anti-fungal medication such as trimethoprimsulfadiazine (TMS), miconazole, or itraconazole (Nichols, D. K. and E. W. Lamirande Froglog, Newsletter of the Declining Amphibian Populations Task Force, August 2001). However, investigators should consider if the medication will interfere with the results of their research.
For additional information you may wish to contact
Donald Sparling
Cooperative Wildlife Research Laboratory
Southern Illinois University
Carbondale, Illinois 62901

Gretchen Flohr
Department of Zoology
Southern Illinois University
Carbondale, Illinois 62901