Norovirus is the term for a group of viruses that causes severe vomiting and diarrhoea. It is a highly contagious virus. People of all ages can get infected and sick with norovirus. You can get norovirus illness many times in your life because there are many different types of noroviruses. Infection with one type of norovirus may not protect you against other types.

Often people refer to the norovirus as stomach flu or stomach bug.  However, norovirus illness is not related to the flu which is caused by the influenza virus.

How do you get infected with norovirus?

Norovirus spreads easily!  People with norovirus illness can shed billions of norovirus particles.  And only a few virus particles can make other people sick.  You can get norovirus from:

  • Having close or direct contact with an infected person.
  • Eating or drinking contaminated food or water.
  • Touching contaminated surfaces and then putting your unwashed hands in your mouth.
  • Contact with faeces of infected humans and animals.

What are the signs and symptoms of norovirus?

Norovirus causes inflammation of the stomach or intestines called acute gastroenteritis.  A person usually develops symptoms 12 to 48 hours after exposure to norovirus.  Most people with norovirus illness get better within 1 to 3 days.

The most common symptoms of norovirus are:

  • Watery or loose diarrhoea.
  • Vomiting (throwing up).
  • Nausea.
  • Stomach pain or cramps.

Other symptoms include:

  • Fever.
  • Headache.
  • Body aches or muscle pain.

When should I see a doctor?

Seek medical attention if you develop diarrhoea that doesn’t go away within several days.  Also, call your doctor if you have severe vomiting, bloody stools, acute stomach pain or dehydration.

For most people, norovirus infection usually clears up within a few days and isn’t life-threatening.  But in some people – especially children, the elderly, pregnant women, and people with compromised immune systems – norovirus infection can cause dehydration, malnutrition and even death.

Warning signs of dehydration include:

  • Fatigue.
  • Dry mouth and throat.
  • Listlessness.
  • Dizziness.
  • Decrease in urination.
  • Dehydrated children might cry with few or no tears. They might be unusually sleepy or fussy.

Diagnosing a norovirus infection

The diagnosis is usually based on symptoms, but norovirus can also be identified from a stool sample.  In children, or if you are immunocompromised, have other health problems, or is pregnant your doctor might recommend a stool test to confirm the presence of norovirus.

How do you prevent the spread of norovirus?

  • Wash your hands thoroughly with soap and water, especially after using the toilet or changing a diaper; before eating, preparing, or handling food; and before giving yourself or someone else medicine.
  • Avoid contaminated food and water, including food prepared by someone who is sick.
  • Wash fruits and vegetables before eating.
  • Cook seafood thoroughly.
  • Dispose of vomit and faecal matter carefully. Soak up material with disposable towels, disturbing it as little as possible, and place it in plastic disposable bags.
  • Disinfect surfaces that might have been contaminated. Use a chlorine bleach solution and wear gloves.
  • Stay home from work, especially if your job involves handling food. You might be contagious for as long as three days after your symptoms end.
  • Children should stay home from school or childcare.
  • Avoid traveling until your signs and symptoms are gone.