Noroviruses: Q&A

Noroviruses are a group of viruses that cause the “stomach flu,” or gastroenteritis (GAS-tro-enter-

I-tis), 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)

Viruses are very different from bacteria and parasites, some of which can cause illnesses similar

to norvirus infection. Viruses are much smaller, are not affected by treatment with antibiotics, and

cannot grow outside of a person’s body.

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.

Illness caused by norovirus infection has several names, including:

respiratory illness caused by influenza virus.

Gastroenteritis refers to an inflammation of the stomach and intestines.

· acute gastroenteritis

· non-bacterial gastroenteritis

· food poisoning (although there are other causes of food poisoning)

· calicivirus infection

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:

norovirus;

their mouth;

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.

Anyone can become infected with these viruses. There are many different strains of norovirus,

which makes it difficult for a person’s body to develop long-lasting immunity. Therefore,

norovirus illness can recur throughout a person’s lifetime. In addition, because of differences in

genetic factors, some people are more likely to become infected and develop more severe illness

than others.

Currently, there is no antiviral medication that works against norovirus and there is no vaccine to

prevent infection. Norovirus infection cannot be treated with antibiotics. This is because

antibiotics work to fight bacteria and not viruses.

Norovirus illness is usually brief in healthy individuals. When people are ill with vomiting and

diarrhea, they should drink plenty of fluids to prevent dehydration. Dehydration among young

children, the elderly, the sick, can be common, and it is the most serious health effect that can

result from norovirus infection. By drinking oral rehydration fluids (ORF), juice, or water,

people can reduce their chance of becoming dehydrated. Sports drinks do not replace the

nutrients and minerals lost during this illness.

Yes. You can decrease your chance of coming in contact with noroviruses by following these

preventive steps:

eating or preparing food.

· Carefully wash fruits and vegetables, and steam oysters before eating them.

illness by using a bleach-based household cleaner.

after an episode of illness (use hot water and soap).

area is kept clean.

Persons who are infected with norovirus should not prepare food while they have symptoms and

may have been contaminated by an ill person should be disposed of properly.