MODIFICATION OF THE POLYETHYLENE-GLYCOL-6000 PRECIPITATION METHOD FORRECOVERING HUMAN AND INDICATOR VIRUSES FROM OYSTERS AND MUSSELS

Human Viruses are a common contaminant of shellfish affected by human sewage wastes. They are difficult to detect as they are not easily sep arated from shellfish tissue. This paper describes a modification of t he polyethylene glycol (PEG) precipitation technique for recovery of e nteroviruses and F-specific bacteriophages from the Pacific oyster (Cr assostrea gigas) and the green-lipped mussel (Perna canaliculus). Modi fications adopted were the use of only the digestive gland tissue for virus extraction, resuspension of the primary PEG pellet in 4 volumes of eluent, and the introduction of a secondary PEG precipitation to re concentrate the virus containing extract. The recovery rate of the vir us extraction process was not affected by introduction of the secondar y concentration step (overall recovery remained at 60-70% of the virus input). The advantages of reduction of tissue residue in the extract, smaller final volume, and the ability to process 2-3 times the number of individual shellfish for the same effort, improve the practicality of the method.