Noroviruses, also known as norwalk-like viruses, are a group of viruses that cause the "stomach flu," or gastroenteritis in people. The symptoms of norovirus illness usually include nausea
, vomiting, diarrhea
, and some stomach cramping. Sometimes people additionally have a low-grade fever, chills, headache
, muscle aches
, and a general sense of tiredness. The illness often begins suddenly, and the infected person may feel very sick. The illness is usually brief, with symptoms lasting only about 1 or 2 days. In general, children experience more vomiting than adults. Most people with norovirus illness have both of these symptoms.
Norovirus disease is usually not serious, although people may feel very sick and vomit many times a day. Most people get better within 1 or 2 days, and they have no long-term health effects related to their illness. However, sometimes people are unable to drink enough liquids to replace the liquids they lost because of vomiting and diarrhea. These persons can become dehydrated and may need special medical attention. This problem with dehydration is usually only seen among the very young, the elderly, and persons with weakened immune systems. There is no evidence to suggest that an infected person can become a long-term carrier of norovirus.
Noroviruses are found in the stool or vomit of infected people. People can become infected with the virus in several ways, including:
- Eating food or drinking liquids that are contaminated with norovirus
- Touching surfaces or objects contaminated with norovirus, and then placing their hand in their mouth
- Having direct contact with another person who is infected and showing symptoms (for example, when caring for someone with illness, or sharing foods or eating utensils with someone who is ill).
Persons working in day-care centers or nursing homes should pay special attention to children or residents who have norovirus illness. This virus is very contagious and can spread rapidly throughout such environments.
Symptoms of norovirus illness usually begin about 24 to 48 hours after ingestion of the virus, but they can appear as early as 12 hours after exposure. Noroviruses are very contagious and can spread easily from person to person. Both stool and vomit are infectious. Particular care should be taken with young children in diapers who may have diarrhea.
People infected with norovirus are contagious from the moment they begin feeling ill to at least 3 days after recovery. Some people may be contagious for as long as 2 weeks after recovery. Therefore, it is particularly important for people to use good handwashing and other hygienic practices after they have recently recovered from norovirus illness.
Norwalk-like virus gained national attention in 2002 and 2003 after hundreds of passengers aboard a number of cruise ships traveling throughout the Carribbean contracted the virus.
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