RESEARCH - Research Summary

Animal Production Theme

Research Summary

Infectious Salmon Anemia (ISA) is a viral disease that has caused major problems for the salmon industry in the Bay of Fundy since it was first diagnosed in 1996. It also presents a threat to the British Columbia salmon industry since the virus has spread to most major salmon producing regions of the world in the last 18 years.

There are number of diagnostic tests available to identify infected fish. However, multiple tests often give contradictory and confusing results. It is essential to know the ability of each of these tests to correctly identify infected fish (i.e. sensitivity of the test) and non-infected fish (i.e. specificity of the test). This project carries out a thorough, structured evaluation of all tests currently in common use and evaluates a new promising diagnostic procedure.

Tests currently used routinely include: virus isolation, reverse transcriptase polymerase chain reaction (RT-PCR), a molecular test for identifying segments of the viral genetic material, and indirect fluorescent antibody test (IFAT), a test in which the virus particles are stained with a dye which makes them fluoresce when viewed under a fluorescent microscope. One new test to be evaluated is an indirect ELISA for detecting antibodies for the ISA virus in exposed fish (i.e. a test which measures the fish’s response to the infection). These tests will be evaluated by submitting common samples taken from fish from several populations. Seven laboratories are participating and a total of 8 tests will be carried out on each fish sampled.

The results of this research will have two major impacts on the salmon aquaculture industry. First, knowing what each test result specifically means will allow for the design of superior disease control programs. Second, knowing the operating characteristics of the test will greatly facilitate the conduct of epidemiologic research into ways of controlling ISA in aquaculture industry. Preliminary results already contributed to a re-evaluation of the disease surveillance program in New Brunswick and increased efforts to standardize tests for different diseases in salmonids.

Network Investigators

Ian Dohoo, Department of Health Management, University of PEI, Charlottetown, PE
Larry Hammell, Department of Health Management, University of PEI, Charlottetown, PE
Henrik Stryhn, Department of Health Management, University of PEI, Charlottetown, PE