Publication Abstract

The development of a quantitive assay for the detection of Norwalk like virus and its application to depuration

K. Henshilwood, W. Dore, S. Anderson and D. Lees

This paper describes for the first time the development of a real time fluorogenic 5' nuclease assay (Taqman) for the quantitative detection of Norwalk-Like Viruses (NLVs) in shellfish. Primer and probe sets were designed for commonly circulating genogroup I and genogroup II NLV strains. The assay showed a better or equal sensitivity compared with a conventional nested reverse transcription-polymerase chain reaction (RT-PCR) when applied than faecal or sewage samples. However the assay appeared to be less sensitive than conventional nested PCR when applied to a range of environmentally contaminated shellfish samples, suggesting that the assay could be further optimised for use with these samples. Despite this limitation, quantitative data on NLV levels in environmentally contaminated shellfish was obtained for the first time. The assay was then used to compare the elimination of NLVs with FRNA bacteriophage during the depuration process. FRNA bacteriophage and NLVs showed similar rates of elimination during depuration trials at 20ºC. Elimination of both FRNA bacteriophage and NLVs was affected by temperature and no reduction of either was observed during depuration carried out at 9ºC.

Reference:

K. Henshilwood*, W. Dore*, S. Anderson* and D. Lees* (2003) The development of a quantitive assay for the detection of Norwalk like virus and its application to depuration. The Congress Book of the 4th International  Molluscan Shellfish Safety Conference, Santiago de Compostela, Spain, July2002.