Norovirus Infection - Causes, Symptoms, Diagnosis, Prevention & Treatment

Norovirus Infection

Dr.Ravi Ram Kiran Gorantla profile Authored by Dr.Ravi Ram Kiran Gorantla on 26 Dec 2014 - 11:01.

Norovirus infection is caused by a group of viruses which cause inflammation of the large intestine and stomach lining which results is sudden onset of severe diarrhea, vomiting and abdominal cramps. This viral infection is highly contagious and spreads through contaminated food and water. It also spreads through close contact with the infected person.

The symptoms of this infection usually begin after 24-48 hours of exposure to the virus. The symptoms last for one to three days. The patients usually recover without any treatment, but infants and elderly people may need treatment for the severe dehydration caused by vomiting and diarrhea.

Norovirus infection usually occurs in crowded environments like hospitals, schools, nursing homes and ships.

Norovirus infection is highly contagious. The viruses are shed in the fecal matter of the infected animals and humans. When food or water is contaminated by this fecal matter of the infected persons, the infection gets transmitted to the consumers of that food.

Methods of transmission of this virus include:

  • Consumption of contaminated food and water
  • Through mouth if the hand has been placed on a contaminated surface
  • Being in close contact with an infected person

Noroviruses are resistant to many disinfectants and can tolerate both hot and cold temperatures which makes it difficult to eradicate the virus.

The signs and symptoms of norovirus infection include the following:

  • Nausea
  • Vomiting
  • Diarrhea
  • Abdominal cramps
  • Fever
  • Malaise
  • Muscle pain

In some persons the signs of infection may not appear but still they can spread the virus to other persons.

The infection is usually diagnosed by looking at the symptoms, but a stool test can be done to confirm the presence of norovirus in immune-compromised patients.

Factors which increase the risk of getting infected by this virus include:

  • Having a weak immune system in the body
  • Living in a place where food is handled with unsanitary procedures
  • Living in close quarters, such as in nursing homes
  • Living with a child who attends preschool or a child care center
  • Staying in hotels, resorts, cruise ships or other destinations with many people in close quarters


Usually norovirus infection clears up in a few days and is not a life threatening infection. But in some people such as infants, elderly people and immune-compromised people, the infection cause malnutrition, severe dehydration and even death.

The warning signs of severe dehydration include fatigue, dizziness, dry mouth and throat and decreased urine output.

There is no antibiotic to kill noroviruses. They do not respond to both antibacterial and antiviral drugs. There is no other treatment for this infection and the recovery usually occurs by itself within a few days based on the immune system of the body.

Plenty of fluids should be given to replace the lost fluids due to dehydration. If the patient is not able to drink lots of fluids then intravenous fluids may be given.

Over the counter anti-diarrheal medication may also be prescribed by the physician.

As this infection is highly contagious it is very important to follow the preventive steps. These steps include:

  • Washing the hands thoroughly especially after using the toilet or changing the diaper of an infant.
  • Wash the fruits and vegetables thoroughly  before eating
  • Cook seafood thoroughly
  • Avoid contaminated food and water which is prepared by an infected person.
  • To avoid the spread of infection through air, dispose the vomit and fecal matter carefully.
  • Chlorine bleach solution should be used to disinfect the contaminated areas.
*Disclaimer This is not medical advice. The content is for educational purposes only. Please contact your doctor for any health care issues.