Norovirus or Norwalk Virus

What is the Norovirus or Norwalk Virus?


Electron microscopic image of Norwalk virusIt is estimated that nearly 65% of nonbacterial gastroenteritis in the US is attributable to Norwalk and Norwalk-like viruses. Approximately 181,000 cases occur annually, with no known associated deaths. Norwalk and Norwalk-like viruses have been associated with outbreaks on cruise ships and in communities, camps, schools, institutions and families. Foods such as raw oysters, cake frosting and salads, as well as drinking water, have been implicated as a common source of viral infection in several outbreaks.

Norwalk and Norwalk-like viruses also are referred to as "noroviruses." infection symptoms include nausea, vomiting, diarrhea and abdominal cramps. The incubation period is between 12 and 48 hours (average of 36 hours, with usual duration of 12-60 hours. Symptoms experienced less often include headache, fever, chills and myalgias. Fluid replacement is the common therapy.

Transmission of Norwalk virus is through the fecal-oral cycle. Although food is an efficient means of transmitting these agents, Norwalk and Norwalk-like viruses can be transmitted via water and by person-to-person contact. Transmission is of special concern for the fishing industry, since molluscan shellfish, being filter feeders, are readily contaminated with the stool-shed viruses present in human sewage.

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  • Article History
    • Revision Date: 6/22/2010

Food Safety Tip of the Day

Be cool, chill out

Chill out refrigerator

Proper cold storage is essential to preventing potential illness-causing bacteria from growing. Cold foods should be kept at 40° F during transporting, storage, and serving. Cooked foods must be cooled to 40° F within 4 hours for safe storage. Use of a thermometer to check refrigerator and food temperatures is a must for monitoring cold foods.

Source: National Restaurant Association Educational Foundation

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