Norovirus
In norovirus, a virus from the Caliciviridae family causes acute gastroenteritis as well as inflammation of the stomach and small intestine. Noroviruses are named after the strain “Norwalk virus,” which caused an outbreak of gastroenteritis in 1968 in a school in Norwalk, Ohio. Four norovirus groups have been identified; each of these is further divided into at least 20 genetic clusters. These viruses are responsible for more than 50% of all food-related outbreaks of gastroenteritis.
Norovirus is a major cause of morbidity and mortality in underdeveloped nations. This condition can be life-threatening to elderly persons, young children, and those who are debilitated or immunosuppressed.
Causes
Norovirus is caused by a single-stranded ribonucleic acid, nonenveloped virus of the genus Norovirus and the Caliciviridae family. The typical incubation period is from 24 to 48 hours; however, some patients have developed symptoms within 12 hours of exposure. Symptoms usually last from 24 to 60 hours; recovery is typically complete, with no long-term consequences.
Noroviruses are typically transmitted by ingestion of fecally contaminated food or water or by direct contact with an individual contagious with the virus. This infection is highly contagious and virulent.
Outbreaks of norovirus due to contaminated food often occur in such settings as schools, restaurants, catered events, nursing homes, and cruise ships. Contamination is usually attributable to an infected individual who prepared or handled food immediately before its consumption. Norovirus caused by water contamination often involves contamination of wells and recreational water by raw sewage.
Complications
Complications of norovirus range from gastrointestinal symptoms to death in very young, elderly, or debilitated persons. Dehydration and electrolyte imbalances are common complications, especially among young or elderly patients, and may necessitate fluid replacement.
