- What are noroviruses?
- What are the symptoms of illness caused by noroviruses?
- What is the name of the illness caused by nororviruses?
- How serious is norovirus disease?
- How do people become infected with noroviruses?
- When do symptoms appear?
- Are noroviruses contagious?
- How long are people contagious?
- Who gets norovirus infection
- What treatment is available for people with norovirus infection?
- Can norovirus infections be prevented?
- Where can I get more information?
What are noroviruses?
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 (NLV)
- 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. Viruses are much smaller, are not affected by treatment with antibiotics and cannot grow outside of a person's body.
- stomach cramping
Occasionally symptoms may also include:
- low-grade fever
- muscle aches
- general sense of tiredness
The illness often begins suddenly and the infected person may feel vary sick. The illness is usually brief, with symptoms lasting only about 1 or 2 days. In general, children experience more vomiting than adults.
- stomach flu - this "stomach flu" is not related to the flu (or influenza), which is a respiratory illness cause by influenza virus
- viral gastroenteritis - the most common name for illness caused by norovirus. 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
How serious is norovirus disease?
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.
Sometimes people are unable to drink enough liquids to replace the liquids they lost because of vomiting and diarrhea. These people 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 or norovirus.
- eating food (see food handler fact sheet) 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.
Are noroviruses contagious?
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.
How long are people contagious?
People infected with norovirus are contagious from the moment they being 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.
Who gets norovirus infection?
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.
What treatment is available for people with norovirus infection?
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 and the sick can be common and is the most serious health effect that can result from norovirus infection.
Drinks to prevent dehydration include:
- Oral rehydration fluids (ORF)
- NOT Sports drinks as these do not replace nutrients and minerals lost
- 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 the surrounding area is kept clean
People 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.
- Proper handwashing procedure (can be printed and posted in bathrooms/food prep areas)
- Norovirus information for food handlers
- Recommendations for Responding to a Public Vomiting Incident
- List of Disinfectants Effective Against Norovirus
- OSHA Fact Sheet: Norovirus Information for Workers