Norovirus infection: symptoms and advice
Noroviruses are very contagious and cause severe stomach upsets. Find out how norovirus can make you ill and how to avoid infection.
Norovirus is a leading cause of food poisoning
People get sick suddenly, usually within a day.
- violent vomiting (often projectile)
- diarrhoea and stomach cramps
- mild fever and chills
- head and muscle aches
- tiredness and nausea.
There is a large risk of dehydration. Drinking fluids is important. The illness usually lasts a few days. It does not usually cause any complications.
How you can be exposed to noroviruses
These viruses are very contagious and hard to kill. They can survive for weeks on some surfaces.
Norovirus is most often spread from person to person. You can also be infected:
- after eating contaminated food
- from contaminated surfaces.
Norovirus may be present in:
- any type of food, including ready-to-eat foods
- produce which has been in contact with sewage
- shellfish harvested from areas where there is untreated sewage.
In New Zealand, commercial shellfish must be harvested from controlled areas to make sure they are safe to eat. You must be careful with shellfish you harvest. Make sure the shellfish is not taken from polluted water.
How you can avoid norovirus infection
- Wash all fruits and vegetables using clean water only.
- Cook food well, especially if someone at your house is sick.
- Check for warning signs before collecting shellfish.
- Don't collect shellfish near sewage outlets.
- Shellfish you collect must be cooked thoroughly. Internal temperature must reach 90°C for 90 seconds to kill the virus. Boil shellfish for 5 minutes (3 minutes if shelled). Lighter cooking, such as steaming or cooking just until shells open, may not kill the virus, and will not ensure that the food is safe to eat.
- Clean hands with soap and hot water. Follow with alcohol-based hand sanitiser, if desired. Note that hand sanitiser alone will not completely destroy norovirus.
- Use a household disinfectant to clean surfaces, utensils, and handles.
If you or someone in your household is sick
- The sick person should not prepare food. They should wait at least 2 days after symptoms have gone away, especially vomiting or diarrhoea.
- Clean and disinfect all surfaces, especially in the bathroom (toilet, taps, handles).
- Wash furnishings, bedding, and clothes used by a sick person. Clean with soap and hot water.
Find out more
Norovirus fact sheet [PDF, 44 KB]
Collecting shellfish and keeping them safe (brochure) [PDF, 1.4 MB]
Who to contact
If you have questions about norovirus in food, email email@example.com