Gastroenteritis - Noroviruses

What are noroviruses?

Noroviruses are a group of viruses that cause the “stomach flu,” or gastroenteritis (GAS-tro-en-ter-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) and caliciviruses.

Symptoms

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. Most people with norovirus illness have both vomiting and diarrhea.

How it is transmitted

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

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.