Noroviruses are a group of related viruses that cause gastroenteritis in humans. This infection is also commonly called epidemic viral gastroenteritis, winter vomiting disease, summer vomiting disease and Norwark virus disease. It occurs worldwide and affects all age groups.
Noroviruses are spread through consumption of faecally contaminated food and water or by direct person to person contact. Environmental contamination may also act as a source of infection eg door handles, crockery and cutlery. Those infected shed the virus in their vomit and stool when symptoms begin and may continue after symptoms have resolved, usually for 48-72 hours but may be longer; they are highly infectious.
Norovirus infection can very quickly spread through closed communities such as nursing homes, hospital wards, children's nurseries and cruise ships.
The incubation period in humans is usually between 24-48 hours; it is highly contagious. The illness is usually self-limiting in 2-3 days.
Signs and symptoms of norovirus infection have a rapid onset and includes projectile vomiting, watery non-bloody diarrhoea, abdominal cramps, nausea and sometimes a mild fever will be present. Vomiting is more common in children.
The most common complication is dehydration and infants, the elderly and those with other health problems are most at risk and may require medical attention.
At present there is no vaccine against norovirus infection and there is no specific treatment. Antibiotics have no effect on this illness as it is caused by a virus.
Treatment consists of relieving the symptoms and replacing the fluids lost by vomiting and diarrhoea. This can be done orally by drinking fluids or rehydration solution or in hospital by intravenous infusion in severe cases.
Recommendations for Travellers
Prevention of foodborne norovirus disease is based on the provision of safe food and water. All travellers should take precautions to ensure that all food and water consumed is safe, whenever possible.
Personal hygiene is essential when travelling and frequent hand washing is important particularly after using the toilet and before eating.
Due to recent norovirus outbreaks on cruise ships, many cruise lines have introduced strict protocols to improve passenger and staff safety. This includes using hand sanitising gel at strategic points throughout the ship eg at embarkation points, at the entrance to dining rooms, library etc. Passengers should comply with this preventive measure. Passengers should also not board the ship if they are suffering from a diarrhoeal illness. Any diarrhoeal illness aboard ship must be reported promptly to the ship's Doctor.
If caring for, or in contact with, an individual with norovirus infection careful handling of potentially infectious material is essential. This includes safe disposal of vomit/diarrhoea, soiled babies napkins or clothing, bedding, unfinished food, crockery and cutlery.
Thoroughly clean and disinfect all contaminated surfaces by using a bleach based household cleaner.
Frequent handwashing cannot be over emphasised.
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