Management of disease as a threat to amphibian conservation



Infectious diseases, such as chytridiomycosis, have been recognized as one major cause of worldwide amphibian population declines. In response to these declines, there are increased demands for zoos and aquariums to develop amphibian captive survival assurance colonies and participate in breeding programmes to produce animals for reintroduction into the wild. To this end, there is a huge responsibility for zoos not only to be familiar with the control of chytridiomycosis and Ranavirus infection, which are the major emerging infectious diseases of wild amphibian populations, but also to recognize the potential threats posed by a myriad of other infectious diseases that have yet to be well described or understood. The example of chytridiomycosis as a disease that has been transmitted by anthropogenic means worldwide makes it essential that zoos make every effort to prevent introduction of deleterious infectious agents into wild amphibian populations as the result of reintroduction programmes. Captive animals destined for eventual release into the wild should be maintained in states of ‘permanent quarantine’ that are well isolated from cosmopolitan zoo collections. Comprehensive disease surveillance and testing programmes should be part of the standard operating procedures for zoo amphibian programmes. Finally, wild amphibians brought into captive survival assurance colonies will present husbandry and disease-control challenges including elimination of pre-existing infectious diseases like chytridiomycosis, control of rhabditiform nematodes and development of a better understanding of amphibian nutrition.