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Last updated January 1, 2014

Emerging Pathogen of Wild, Farmed Bullfrogs Bred for the International Restaurant Trade

Rolando Mazzoni*, Andrew Cunningham**, Peter Daszak***, Ada Apolo*, Eugenio Perdomo, Gustavo Speranza*, Centers for Disease Control & Prevention, Emerging Infectious Diseases 9(8):03-0030 (edited)

Chytridiomycosis is an emerging disease responsible for a series of global population declines and extinctions of amphibians. We report the causative agent, Batrachochytrium dendrobatidis, in North American bullfrogs (Rana catesbeiana) farmed for the international restaurant trade. Our findings suggest that international trade may play a key role in the global dissemination of this and other emerging infectious diseases in wildlife.

Cutaneous chytridiomycosis is an emerging fungal disease of amphibians responsible for a series of mass die-offs, population declines, and extinctions of amphibians on a global scale (1,2). In wild, susceptible species, chytridiomycosis may be able to cause catastrophic population loss, sometimes completely removing local populations (2).

This disease is a serious threat to the conservation of wild amphibians, and policy measures to control amphibian movements have been established by at least one authority (Parks and Wildlife Commission of the Northern Territory, Australia; Bill Freeland, pers. comm.). Chytridiomycosis is caused by a zoosporic fungus, Batrachochytrium dendrobatidis, which develops solely within keratinized cells (3), causing extensive hyperkeratosis and death by an-as-yet-unknown mechanism (1,4,5).

Chytridiomycosis is a key example of an emerging infectious disease in wildlife (6,7). The most important factor driving the emergence of such wildlife diseases is the anthropogenic introduction of pathogens into new geographic areas (pathogen pollution) (6­9).

We report on B. dendrobatidis in captive bullfrogs, which was identified during an episode of unusually high death rates of unknown cause and which implicates a relatively new food animal trade in the spread of this disease.

More information regarding the study can be found at the CDC's EID website.

*Instituto de Investigaciones Pesqueras, Montevideo, Uruguay;
**Institute of Zoology, London, UK; and
***Consortium for Conservation Medicine, Palisades, New York, USA

Edited article reprinted from ProMED