Molecular characterization, surveillance and pathogenicity trials of nodaviruses strains of Atlantic Canada

Description

Nodaviruses cause high mortality levels in hatchery-reared larvae and juveniles and is a worldwide problem affecting over 30 marine fish species. In the Atlantic provinces, nodavirus was found in wild winter flounder from Passamaquoddy Bay, NB, in 2000. Severe losses have occurred in cultured Atlantic cod in Nova Scotia, Newfoundland and New Hampshire, and in haddock in New Brunswick in 2002.

Infections of nodaviruses are one of the key constraints of the marine fish farming industry and we need to evaluate the potential pathogenicity of these organisms. For example, nodavirus strains in Europe are reported to be very pathogenic to larval halibut. Preliminary work done on nodavirus strains found here has shown that they are divergent from European ones. One of our objectives is to gather genomic sequences from the different NNV isolates collected during these outbreaks and through screening of wild fishes samples. Another objective is to determine if strains isolated from Atlantic Canadian cod and haddock could potentially cause disease in halibut larvae.

For the aquaculturist and broodstock producer, non-lethal screening of broodfish is imperative so fish carrying nodavirus can be eliminated from the spawning population. Lack of important basic knowledge on nodavirus transmission and detection in tissues such as blood and reproductive fluids impairs fish health risk management decisions. Another objective of this project is to develop and optimize sensitive detection methods such as cell culture and amplification of viral genome (e.g., RT-PCR) for these tissues in an attempt to detect NNV non-lethally.

Program Name

Aquaculture Collaborative Research and Development Program (ACRDP)

Year(s)

2003 - 2005

Ecoregion(s)

Atlantic: Gulf of Maine, Scotian Shelf

Principal Investigator(s)

Nellie Gagné
Email: Nellie.Gagne@dfo-mpo.gc.ca