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Identification and quantification of Kudoa thyrsites -specific DNA in seawater



The parasite Kudoa thyrsites can cause soft-flesh syndrome that affects the flesh quality in post-harvest Atlantic salmon farmed in British Columbia (BC). Although fish infected with the parasite show no clinical signs of disease, muscle in the processed fillet rapidly deteriorates, resulting in economic losses to the industry. Currently there are no vaccines or approved treatments for Kudoa thyrsites, however researchers are exploring candidate treatments. Knowledge is limited on the life cycle of Kudoa thyrsites, and there are no vaccines or approved treatments for the parasite. Most species of Kudoa have only been identified from within the specific cells or tissues of their fish hosts. All other aspects of their life cycle, including how the parasite enters and migrates within the fish, and the alternate host species are unknown, however it is hypothesized that the infective stages occur in seawater.

The proposed research will develop a test for the detection of the waterborne fish-infective stage of K. thyrsites. The method will be validated and used to screen water samples from commercial production sites historically known to be at risk for K. thyrsites infection. These samples will be taken at various depths and times. This will help assess the seasons and water depths when changes occur in the abundance of the infective stage, in the marine environment.

Developing monitoring techniques and understanding the seasonality and intensity of the waterborne stages of K. thyrsites will help managers to ensure fish are produced in appropriate areas. Measuring levels of K. thyrsites DNA in water will provide a reliable estimate of the risk and severity of exposure at production sites. Data from this research could also contribute to the development of drug treatments, or vaccines.

Program Name

Aquaculture Collaborative Research and Development Program (ACRDP)


2012 - 2013


Pacific: Vancouver Island West Coast

Principal Investigator(s)

Simon Jones

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