Validity of using serological tests for diagnosis of diseases in wild animals

Transposition of diagnostic tests used in domestic livestock species to free-ranging and captive wildlife species has two problems. First, most existing tests have not been adequately validated in domestic livestock. Second, assumptions that a serological test will perform identically in wildlife and livestock species may not be correct, due to differences in pathogenic strains and serovars, host serological responses, and exposure to organisms of similar antigenic structure which produce cross-reacting antibodies. Some assays require species-specific reagents/test components which might not be commercially available, and most assays have not been standardized. The authors outline the principles involved in the evaluation of a serological diagnostic test, and provide examples of how knowledge of test sensitivity and specificity can be used to estimate true prevalence, to determine whether a population is infected, and to facilitate management decisions with regard to animal translocations.