The norovirus group of viruses are the most common cause of gastroenteritis (upset stomach) in the UK. 

Symptoms of a norovirus infection include nausea, vomiting, diarrhoea and in some cases a fever, headache, stomach cramps and aching limbs. Symptoms can last for 12 to 60 hours, but most people recover within two days.

Although people can suffer from norovirus at any time of the year, there is more of it about in communities in the winter months from October through to April.

How noroviruses are spread
It is estimated that noroviruses infect between 600,000 and one million people in the UK every year. Norovirus infections occur in people of all ages and outbreaks of the illness are common, particularly within contained environments such as hospitals, nursing homes and schools. To avoid spreading the virus, it is therefore extremely important not to visit communities such as hospitals, nursing homes and schools for 48 hours if you have had any symptoms of norovirus.

Norovirus spreads very easily from person to person. The virus that causes norovirus lives in the gut and so is present in vomit and stools. It can live outside the body for many hours on unwashed hands and contaminated surfaces including door handles.

Noroviruses can be spread through contact with an infected person, through contact with surfaces or objects that are contaminated with the virus, or by consuming contaminated food or water.

After having a norovirus infection it is possible to become infected again, because immunity to the virus only lasts for a short period of time.

• Stay at home
• Take paracetamol to relieve symptoms of any fever
• Drink plenty of water to replace the fluids lost through diarrhoea and vomiting. This prevents dehydration.

Drinking plenty of fluids is particularly important for young children and the elderly, who are more prone to dehydration.

Try to eat a light diet of foods that are easy to digest, such as soup, rice, pasta and bread. Babies should be given their normal feed throughout.

If your symptoms continue for more than three days or you feel severely dehydrated, seek medical attention immediately.

You can take the following steps to help stop the virus spreading:

• Wash your hands frequently and thoroughly, particularly after using the toilet and before preparing food.
• Do not share towels and flannels.
• Disinfect any surfaces or objects that could be contaminated with the virus. It is best to use a bleach-based household cleaner. Always follow the instructions on the cleaning product.
• Wash any clothing or bedding that could have become contaminated with the virus. Wash the items seperately and on a hot wash to ensure that the virus is killed.
• Flush away any infected faeces or vomit in the toilet and keep the surrounding toilet area clean.
• Avoid direct contact with others, and preparing food for others if you have a norovirus infection until at least 48 hours after your symptoms have gone. You may still be contagious, even though you no longer have sickness or diarrhoea.

If you have a norovirus infection, avoid direct contact with others, and preparing food for others, until at least 48 hours after your symptoms have gone. You may still be contagious, even though you no longer have sickness or diarrhoea.

Avoid visiting hospitals if you have had the typical symptoms of norovirus infection in the past 48 hours. Norovirus infection is more serious and even more easily spread among people who are already ill. You may be asked to rearrange outpatient appointments if you have had recent symptoms.

To find out more you can log on to NHS Choices or the Health Protection Agency.