Abstract

A fatal outbreak of amphibian chytridiomycosis in a group of critically endangered Kihansi spray toads (Nectophrynoides asperginis) prompted institution-wide testing for Batrachochytrium dendrobatidis (Bd) infection in the amphibian collections of the Wildlife Conservation Society (WCS). Animal sampling was accomplished following established protocols.^1,2 A total of 363 samples from 45 amphibian species at the WCS’ four zoological parks and one aquarium were collected and tested over a period of 5 months. Quantitative real-time TaqMan PCR (qPCR) for Bd was performed by the Molecular Disease Laboratories at San Diego’s Institute for Conservation Research. Several individuals belonging to 7 of the species tested (dyeing arrow frog [Dendrobates tinctorius]; green and black poison arrow frog [Dendrobates auratus]; splashback poison arrow frog [Dendrobates galactonotus]; red-eyed tree frog [Agalychnis callidryas]; grey tree frog [Hyla versicolor]; wood frog [Rana sylvatica]; tiger salamander [Ambystoma tigrinum]; and aquatic caecilians [Typhlonectes natans]) were positive for Bd qPCR. None of the test-positive animals showed any evidence of clinical disease. All PCR-positive animals were treated prophylactically and subsequently re-tested. The results of this survey highlight the value of collection-wide amphibian Bd surveillance in identifying clinically unaffected animals and the importance of disease screening as part of routine quarantine protocols to prevent introduction of this disease into established animal collections.

Literature Cited

1.  Hyatt AD, Boyle DG, Olsen V, Boyle DB, Berger L, Obendorf D, et al. Diagnostic assays and sampling protocols for the detection of Batrachochytrium dendrobatidis. Dis Aquat Org. 2007;73:175–192.

2.  Berger L, Speare R, Skerratt LF. Distribution of Batrachochytrium dendrobatidis and pathology in the skin of green tree frogs Litoria caerulea with severe chytridiomycosis. Dis Aquat Org. 2005;68:65–70.