Optimization of diagnostic methodologies for the detection and life history pathogenesis studies of Betanodavirus in production and broodstock Atlantic cod (Gadus morhua)
The presence of betanodavirus in wild Atlantic Canadian cod adults was reported in 2002, with clinical disease recently confirmed in hatchery-reared cod juveniles from Newfoundland, Nova Scotia, New Brunswick and New Hampshire-USA. These clinical outbreaks have resulted in high levels of morbidity and mortality, supporting the hypothesis that betanodavirus poses a serious threat to the successful commercialization of Atlantic cod aquaculture in Canada.
The Atlantic Canadian strains isolated from winter flounder, Atlantic cod and haddock are highly similar with respect to the amino acid sequence of the coat proteins and are all members of the barfin flounder clade (Johnson et al. 2002, Gagné et al. 2004).
The development of rapid, cost-effective pathogen screening methods with known performance characteristics for betanodavirus is extremely important for the Atlantic cod aquaculture industry in Canada and the rigorous assessments of diagnostic test performance (i.e. sensitivity, specificity, and inter-laboratory agreement) in clinical samples is required to make appropriate decisions regarding pathogen detection and control (Nérette et al. 2005a, 2005b).
Within this proposal we will develop new or modify existing diagnostic methods for use on Atlantic Canadian strains of betanodavirus, eg. virus culture in SSN1 and E11 cell lines, RT-PCR and Real Time PCR, and histological (in-situ hybridization) methods (Gagné et al. 2004, Iwamoto et al. 2005). We will also establish test sensitivity and specificity and optimize the application of these methods for the screening of different life history stages and tissues of both clinically and covertly ill Atlantic cod. Veterinarians, fish disease diagnostic laboratories and researchers will be able to apply quickly our results to reduce and possibly alleviate the problem of disease caused by nodavirus in Atlantic cod culture.
2006 - 2008
Atlantic: Gulf of Maine, Scotian Shelf
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