Norovirus Gastroenteritis (Gastric Flu)

Inflammation of the stomach and intestines caused by a virus called norovirus, resulting in vomiting, diarrhoea or cramps.

Definition & Characteristics

Gastroenteritis means inflammation of the stomach and intestines. It may be caused by:

  • infection by certain bacteria, viruses or parasites, or
  • certain medications or medical conditions

Viral gastroenteritis is an infection caused by many different viruses including rotaviruses, noroviruses, adenoviruses, sapoviruses and astroviruses. It is sometimes called “gastric flu” although it is not related to influenza.


Symptoms usually include nausea, vomiting, diarrhoea and abdominal cramps. 

In general, children experience more vomiting than adults. Low-grade fever is present in about half of cases. The illness begins suddenly and is usually brief, lasting about 1 or 2 days.

How Gastric Flu Spreads

The viruses that cause gastroenteritis are spread in several ways, including:

  • Eating food or drinking liquids that are contaminated.
  • Touching surfaces or objects that are contaminated, and then placing their hand in their mouth.
  • Having direct contact with another person who is infected and showing symptoms (e.g, when caring for someone with illness, or sharing foods or eating utensils with someone who is ill).

What To Do If You Have Gastric Flu

Gastroenteritis is usually brief in healthy persons.

The most serious health effect is dehydration. Persons become dehydrated because they are unable to replace the fluids they lost due to vomiting and diarrhoea. The symptoms for dehydration include dry or sticky mouth, thirst, lethargy, constipation and little or no urination.

This is commonly seen among the very young, the elderly, and persons with weakened immune systems. Those who become dehydrated should seek medical attention immediately.

A person who has gastroenteritis can reduce their risk of becoming dehydrated by drinking oral rehydration fluids, juice, or water.

Those who are diagnosed with gastroenteritis should refrain from attending school or work until they are well. They should not prepare food while having symptoms.

Precautions You Can Take

You can reduce your chance of contracting gastric flu by following these preventive steps:

  • Wash your hands frequently, especially after toilet visits and changing diapers and before eating or preparing food.
  • Wash fruits and vegetables thoroughly before consumption.
  • Ensure food (especially shellfish) is thoroughly cooked before consumption.
  • Clean and disinfect contaminated surfaces thoroughly immediately after an episode of illness by using the proportion of 1 part bleach to 9 parts water.
  • 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 that the surrounding area is kept clean.
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