Sources of Shellfish in Outbreaks of Probable Viral Gastroenteritis: Implications for Control

Shellfish have been identified as vehicles of foodborne enteric disease in the United States since the first part of the twentieth century. Between 1900 and 1983, 198 incidents or outbreaks involving 8,659 cases were reported nationally. In New York State, reports of shellfishborne gastroenteritis and/or hepatitis A began to increase in 1981, when one outbreak involving 234 cases of gastroenteritis was reported. In subsequent years, the following were reported: 1982, 103 outbreaks of gastroenteritis involving 1,017 cases and 10 cases of hepatitis A; 1983, 33 outbreaks of gastroenteritis involving 504 cases; 1984, 15 gastroenteritis outbreaks and 256 cases; and the first five months of 1985, 10 outbreaks of gastroenteritis involving 98 cases. States, countries or provinces identified as sources of shellfish implicated in these outbreaks included: New York, Massachusetts, Rhode Island, England North Carolina and Prince Edward Island. The source investigations were seriously impaired by numerous inadequacies in current shellfish-tagging regulations and the manner in which these are enforced. Possible solutions to prevent further shellfishborne disease outbreaks include: (a) improve shellfishborne disease surveillance and reporting; (b) embargo shellfish sold by shippers implicated in disease outbreaks; (c) adopt strict state and federal laws to control the sanitary quality of all shellfish; (d) accomplish greater participation in the Interstate Shellfish Sanitation Conference; (e) provide an adequate number of enforcement officers; (f) develop a microbiologic growing water and/or product standard that assures viral as well as bacteriologic safety; (g) properly classify shellfish-harvesting waters; (h) mandate a manifest-type tagging system; (i) strictly enforce wholesale and retail shellfish-tagging requirements; (j) require depuration of all shellfish sold; and (k) advise the public against the consumption of raw or partially cooked shellfish. If these or other approaches fail to prevent morbidity, a ban on the sale of raw shellfish may be the only solution.