Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2006
Publication Date: 3/18/2007
Citation: Richards, G.P. 2007. An overview of virus extraction and assay methods. Abstract. 6th International Conference on Molluscan Shellfish Safety, Blenheim, New Zealand. p.78.
Technical Abstract: Enteric viruses, particularly norovirus and hepatitis A virus, are major contaminants of molluscan shellfish and can cause illness. A host of procedures have been developed for the extraction of viruse from shellfish and for their assay. Some extraction and assay methods focused on detection of vaccine strains of poliovirus as a possible indicator for other enteric viral pathogens. Plaque and cytopathogenicity assays, radioimmunoassay and luminescent immunofocus assays were developed to detect virus capable of replication in cell cultures, while enzyme immunoassays and radioimmunoassays were used to detect the presence of viral antigens. The advent of molecular biology opened the way for reverse transcription –polymerase chain reaction (RT-PCR) and real-time RT-PCR. In spite of the advances made, the extraction procedures are time-consuming and complex. Assay methods suffer from limitations including the presence of inhibitory compounds in the extracts, and the inability to differentiate infectious from inactivated virus using molecular methods. This presentation describes: a) general procedures for virus extraction from seawater and shellfish, b) cell-culture-based and molecular methods for virus assay, c) limitations in the procedures, d) factors important to the interpretation of results, and e) future directions for research and for the regulation of molluscan shellfish safety.