Electron micrograph(TEM) of Norovirus
What is Norovirus?
Noroviruses are a group of viruses that cause the "stomach flu" or gastroenteritis in people. The term norovirus was recently approved as the official name for this group of viruses. Several other names have been used for noroviruses, including:
- Norwalk-like viruses (NLVs)
- Caliciviruses (because they belong to the virus family Caliciviridae)
- Small round structured viruses
Viruses are very different from bacteria and parasites, some of which can cause illnesses similar to norovirus infection. Like all viral infections, noroviruses are not affected by treatment with antibiotics, and cannot grow outside of a person's body.
How do people get norovirus infections?
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.
Can I catch norovirus from someone?
Yes, norovirus is 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. Therefore, it is particularly important for people to use good handwashing and other hygienic practices after they have recently recovered from norovirus illness.
How can I protect myself and my family from getting sick with norovirus?
You can decrease your chance of coming in contact with noroviruses by following these preventive steps:
- Frequently wash your hands, especially after toilet visits and changing diapers and before eating or preparing food.
- Carefully wash fruits and vegetables, and steam oysters before eating them.
- Thoroughly clean and disinfect contaminated surfaces immediately after an episode of illness by using a bleach-based household cleaner.
- Immediately remove and wash clothing or linens that may be contaminated with virus after an episode of illness (use hot water and soap).
- Flush or discard any vomitus and/or stool in the toilet and make sure that the surrounding area is kept clean.
Persons who are infected with norovirus should not prepare food while they have symptoms and for 3 days after they recover from their illness. Food that may have been contaminated by an ill person should be disposed of properly.
What are the signs of norovirus?
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. In most people the illness is self-limiting with symptoms lasting for about 1 or 2 days. In general, children experience more vomiting than adults. Most people with norovirus illness have both of these symptoms.
Is there a cure for norovirus?
There is no cure for norovirus, however almost all people who get norovirus infection recover completely without any long-term problems. The most important thing to do for people with norovirus infection is prevent severe loss of fluids (dehydration). Dehydration among young children, the elderly, and the sick, can be common, and it is the most serious health effect that can result from norovirus infection. By drinking oral rehydration fluids, juice, or water, people can reduce their chance of becoming dehydrated. Sports drinks do not replace the nutrients and minerals lost during this illness. Medications, including antibiotics (which have no effect on viruses) and other treatments, should be avoided unless specifically recommended by a physician.
Useful norovirus links and documents