Norwalk-like Viruses Associated With A Gastroenteritis Outbreak Following Oyster Consumption.

In late October 1991, an outbreak of gastroenteritis, following the consumption of raw oysters involving more than 200 people, was reported in five locations in Quebec, Canada. Bacteriological analysis of the oysters involved indicated low levels of fecal coliforms, but direct electron microscopy of stool samples obtained from two people involved in the outbreak revealed that both contained 27-34 nm, small, round Norwalk-like viruses. Immunoelectron microscopy, using acute sera obtained from these individuals and convalescent serum from another person related to the outbreak, revealed antibody coatings on these Norwalk-like viruses with all three sera.