VIRUSES IN MUSSELS - PUBLIC-HEALTH IMPLICATIONS AND DEPURATION

Studies were conducted in the common musset (Mytilus spp.) to evaluate the public health implications derived from shellfish contamination w ith human pathogenic enteric viruses. In bioaccumulation experiments, we could verify that after 6 h of immersion of mussels in marine water contaminated with high levels of clay-associated enteric adenovirus ( type 40) and human rotavirus (type 3), between 4 to 56% of the seeded viruses were adsorbed to shellfish tissues, mainly in the gills and di gestive tract. We investigated the occurrence of wild-type enteric vir uses in mussels from sites with different levels of fecal pollution. P athogenic viruses could be detected in mussels from areas that, follow ing current standards based on bacteriological quality, should be rega rded as unpolluted, safe for swimming, and suitable for harvesting she llfish. Cooking experiments performed with contaminated mussels reveal ed that 5 min after the opening of the mussel valves, rotaviruses and hepatitis A virus could still be recovered in steamed shellfish. Under commercial depuration conditions, health-significant enteric viruses, such as rotavirus and hepatitis A virus, could be recovered from biva lves after 96 h of immersion in a continuous how of ozonated marine wa ter. Routine screening of bivalves for the presence of health-signific ant enteric viruses before public consumption may help in the preventi on of outbreaks among shellfish consumers.