Norwalk viruses
Last reviewed: 23.04.2024
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In 1968, during the outbreak of OKZ among schoolchildren and teachers in the city of Norwalk (USA), the agent of this outbreak, a virus called Norwolk, was discovered. It was identified by the method of immune electron microscopy. The virus has a spherical shape and a diameter of 27-32 nm. Similar viruses have been detected in many other outbreaks of gastroenteritis in England, the United States, and Australia.
In antigenic respect, they turned out to be inhomogeneous, at least 4 serovariants were established. The genome is a single-stranded, unfragmented RNA of positive polarity. The virus is assigned to the Caliciviridae family; these are the most frequent pathogens of gastroenteritis in children older than 4 years and in adults. The virus is released in the first 48-72 hours after the disease, it is very stable in the external environment. It spreads by the fecal-oral route through infected water and food.
The incubation period is 18-48 hours. The onset of the disease is acute, in 70% of cases, vomiting, in 65% - diarrhea. The disease lasts 2-3 days. In elderly people, a fatal outcome is possible. Diagnosis of the disease is difficult due to the lack of laboratory test systems and the inability to cultivate the virus in vitro.
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