Consumption Of Raw Shellfish Research Articles

Clinical and ecological characteristics of Vibrio vulnificus in the northeastern United States.

Multiple seawater sites in the northeastern United States, particularly Long Island Sound, and shellfish from Long Island Sound were sampled from April to November for 3 successive yr, 1983-1985. Hospitals in coastal and metropolitan areas of Connecticut were surveyed for the same 3-yr period, Vibrio vulnificus can be found in these waters during the summer months. The appearance of these virulent bacteria in both seawater and shellfish are a function of the water temperature; no V. vulnificus could be isolated until the temperature was approximately 17 degrees C. Although the risk of infection is small, as shown by isolation of this organism from patients, certain high-risk groups exist. Consumption of raw shell fish during the summer months should be discouraged in people with liver disease or patients on immunosuppressive therapy.

Widespread Outbreaks of Clam- and Oyster-Associated Gastroenteritis

Consumption of raw shellfish has long been known to be associated with individual cases and sporadic outbreaks of enteric illness. However, during 1982, outbreaks of gastroenteritis associated with eating raw shellfish reached epidemic proportions in New York State. Between May 1 and December 31, there were 103 well-documented outbreaks in which 1017 persons became ill: 813 cases were related to eating clams, and 204 to eating oysters. The most common symptoms were diarrhea, nausea, abdominal cramps, and vomiting. Incubation periods were generally 24 to 48 hours long, and the duration of illness was 24 to 48 hours. Bacteriologic analyses of stool and shellfish specimens did not reveal a causative agent. Norwalk virus was implicated as the predominant etiologic agent by clinical features of the illness and by seroconversion and the formation of IgM antibody to Norwalk virus in paired serum samples from persons in five (71 percent) of seven outbreaks in which testing was done. In addition, Norwalk virus was identified by radioimmunoassay in clam and oyster specimens from two of the outbreaks. Determining the source of the shellfish was not always possible, but northeastern coastal waters were implicated. The magnitude, persistence, and widespread nature of these outbreaks raise further questions about the safety of consuming raw shellfish.

Infectious Disease Hazards of Landspreading Sewage Wastes

AbstractMajor increases are currently taking place in the United States in the application of sewage wastes to agricultural land. This paper reviews literature relating to the question of whether such applications involve hazard from human disease organisms. Evidence on the matter is still inadequate. Processed sewage wastes often contain residual pathogenic viruses, bacteria, cysts of protozoa, and ova of helminths, but most sewage‐related disease outbreaks have been attributed to use of raw sewage waste water, raw sludges, or night soils on food crops consumed raw, to contamination of drinking water from septic tanks, or to consumption of raw shellfish from sewage‐polluted waters. Although subject to relatively high levels of exposure to pathogens in aerosols, waste water treatment plant workers appear to be unaffected, but data on this are limited. Percolation of waste water at a moderate rate through soils of medium to fine texture removes most bacteria and viruses; pathogen movement in surface runoff water may present a greater hazard for spreading disease. Techniques that completely disinfect sludges may fail to stabilize them so that putrefaction is a problem. Properly conducted composting stabilizes raw sludge and destroys most pathogens. Certain fungi and actinomycetes generated during composting may have allergenic potentialities of import for workers at sludge composting sites.