Norovirus

About norovirus and how to reduce the risk of spreading the virus.
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Norovirus is commonly known as the winter vomiting bug. It causes an estimated three million cases of diarrhoea and vomiting each year. 

Although the symptoms of norovirus can be unpleasant, it is considered a mild infection. This is because it is usually short-lived and most people get better without medical treatment.

You are most likely to catch norovirus by coming into contact with an infected person but it can also be spread by contaminated food. 

Norovirus is estimated to be the third most common cause of foodborne illness in the UK. Our research estimated that it was responsible for 74,000 cases of food poisoning in the UK in 2009. 

Extension to the IID2 study: identifying the proportion of foodborne disease in the UK

Viruses

Viruses are tiny, often highly contagious pathogenic agents which cause disease. Foodborne viruses account for an estimated 18% of the UK’s food poisoning cases – a significant proportion.

Viruses can be spread between hosts in different ways such as through:

  • bodily fluids - for example, HIV
  • the air - for example, influenza
  • ingestion - for example, norovirus 

Unlike bacteria, viruses are not technically considered living organisms. Norovirus  can survive and remain infectious in foods and the environment for prolonged periods of time and can often survive under harsher conditions than bacteria.

How norovirus spreads

Norovirus can contaminate food and water and enters the body by being ingested and inhaled through the mouth or nose.  Norovirus causes infection once it has reached the gut.

It can also spread through contact with the faeces or vomit of an infected person. Norovirus can remain infectious in the environment for several months. 

To prevent you passing norovirus on to your family and friends via the food you’re preparing, it’s vital that you follow good personal hygiene practices.

It’s also essential that you are careful about cleaning and avoiding cross-contamination when transporting, preparing and storing food.

Viruses such as norovirus cannot multiply in food, but they can survive there for long periods of time. Outbreaks of norovirus have been caused by infected oysters  and fresh produce such as berries and salad. 

Evaluating the effectiveness of depuration in removing norovirus from oysters

Food handlers and norovirus transmission: Social science insights