Enteric viruses in molluscan shellfish.

One hundred and thirty-seven bivalves were collected for environmental monitoring and the market; all the samples were analysed by RT-PCR test. Bacteriological counts meeting the European Union shellfish criteria were reached by 69.5% of all the samples, whereas the overall positive values for enteric virus presence were: 25.5%, 18.2%, 8.0% and 2.1% for Rotavirus, Astrovirus, Enteroviruses, Norovirus, respectively. Mussels appear to be the most contaminated bivalves, with 64.8% of positive samples, 55.7% and 22.7% respectively for clams and oysters, whereas in the bivalves collected for human consumption 50.7% were enteric virus positive, as compared to 56.4% of the samples collected for growing-area classification. The overall positive sample was 54.0%.