What are noroviruses?
Norovirus is a virus that causes what is often called the stomach flu *(although it is not the influenza virus) and is marked by symptoms including vomiting and diarrhea in people.
What are the symptoms of illness caused by noroviruses?
Norovirus illness usually begins 24-48 hours after exposure, but can appear as early as 10 hours after exposure.
Symptoms usually include nausea, vomiting, diarrhea and stomach cramping. Sometimes people have a low-grade fever, chills, headache, muscle aches and general fatigue and tiredness. The illness-related symptoms typically last only one or two days.
How serious is norovirus disease?
Norovirus disease is usually not serious, but people with the norovirus may feel very sick. Most people get better within one or two days and have no long-term health effects from the illness. Sometimes people are unable to drink enough liquids to replace what they lose from vomiting and diarrhea, and they can become dehydrated and need to see a doctor. This problem usually occurs only among the very young, the elderly, and persons with weakened immune systems.
How is norovirus spread?
Noroviruses are very contagious and spread easily from person to person. The virus is found in the stool and vomit of infected people. People can become infected in several ways, including eating food or drinking liquids contaminated by infected food handlers, touching surfaces or objects contaminated with norovirus and then touching their mouth before hand washing or having direct contact with another person who is infected and then touching their mouth before hand washing. Outbreaks also have occurred from eating undercooked oysters harvested from contaminated waters - cooking kills the virus. Drinking water contaminated by sewage can also be a source of these
viruses. Persons working in day-care centers or nursing homes should pay special attention to children or residents who have norovirus illness. This virus can spread quickly in these places.
How long are people contagious?
People infected with norovirus are contagious from the moment they begin feeling ill to at least three days after recovery. Some people may be contagious for as long as two weeks after recovery. Therefore, good hand washing is important. Persons infected with norovirus should not prepare food while they have symptoms and for three days after they recover. Infected people do not become long-term carriers of norovirus.
Who gets norovirus infection?
Anyone can become infected with these viruses. Because there are many different strains of norovirus, norovirus infection and illness can re-occur throughout a person’s lifetime.
What treatment is available for people with norovirus infection?
Currently, there is no specific medication or vaccine for norovirus. Norovirus infection cannot be treated with antibiotics. By drinking fluids, such as juice or water, people can reduce their chance of becoming dehydrated.
Sports drinks do not replace the nutrients and minerals lost during this illness.
Do infected people need to be excluded from school, work or daycare?
Since the virus is passed in vomit and stool, children should not go to daycare or school while they have diarrhea or vomiting. Once illness ends, children can return to daycare, but hand washing must be strictly monitored. Persons who work in nursing homes, take care of patients, or handle food should stay out of work until at least three days after symptoms end.
Can norovirus infections be prevented?
You can decrease your chance of coming in contact with noroviruses by:
- Frequent hand washing with warm water and soap
- Promptly disinfecting contaminated surfaces with household chlorine bleach-based cleaners
- Washing soiled clothing and linens
- Avoiding food or water from sources that may be contaminated
- Cooking oysters completely to kill the virus
A GI illness outbreak is defined as two or more persons in the same facility (e.g., nursing home, school, prison) or group (e.g., sport team), experiencing an acute onset of diarrhea, nausea, or vomiting. Outbreaks of GI illness in Kentucky are reported to the district or county health department in which the outbreak is occurring. If the district or county health department cannot be reached, contact the Kentucky Department for Public Health at 1-888-9REPORT (1-888-973-7678).
See 902 KAR 2:020 Section 5 for more information regarding outbreaks.