Selection and interpretation of diagnostic tests in aquaculture biosecurity

Abstract

In biosecurity-related activities in aquaculture, diagnostic tests are commonly used to (1) demonstrate freedom from infection in a facility, (2) screen aquatic animals prior to introduction to the receiving facility, (3) detect infected animals as early as possible during a quarantine period, and (4) confirm suspicious or clinical case(s). The interpretation of test result(s) is indicative of the true infection status at the individual and at the group levels and has direct implications in completing the stepwise process for Effective Veterinary Biosecurity as proposed by the International Aquatic Veterinary Biosecurity Consortium. The confidence regarding a test result depends on the anticipated level of infection in the investigated aquatic animal population and on the diagnostic sensitivity and specificity of the tests. Depending on the testing intended purpose, the test of choice or combination of test may vary and is primarily based on the test diagnostic sensitivity or specificity. Additional strategies for maximizing the chance of a test result to be true are described in the context of each testing activity and targeted unit of interest (i.e., individual fish or group of fish).