WINTER vomiting disease is the most common cause of gut infection in the UK. Most years there are between 600,000 and a million cases in England alone.

Last winter saw the disease hit record numbers as almost three million people succumbed to the sickness and diahorrea bug, which is not normally dangerous but is certainly unpleasant.

Winter vomiting disease is caused by infection with the small round structured virus (SRSV), also known as the Norwalk-like virus or norovirus.

The virus lives in the gut and is passed from person to person by poor hygiene. For example, not washing hands properly after using the toilet and then touching toilet handles, seats, and door handles.

It can also be spread when someone vomits and small particles containing the virus enter the air.

Although the bug can occur at any time, it has become synonymous with winter.

Arun Patel, associate director of public health for NHS South West Essex, says: “We notice the number of cases of the bug start to rise from October most years. That is why it has been dubbed the winter vomiting bug.

“Although extremely infectious, it’s only harmful if the elderly or very young catch it.

“This is because they are far more susceptible to the effects of dehydration that sickness can lead to.

“For example, babies who get the bug may need to go to hospital because they will need some immediate form of rehydration.”

Only very small amounts of the virus are needed to cause illness and it’s easily spread in closed communities, such as hospitals, schools and cruise ships.

The incubation period is usually between 24 and 48 hours. This is followed by severe and sudden projectile vomiting, diarrhoea and fever symptoms, which last about 48 hours.

Although it is particularly virulent, norovirus is rarely dangerous. There’s no specific treatment, but rest and drinking plenty of water are recommended. Dr Patel says: “We are advising people not to go to hospital or to their GP unless absolutely necessary. This is because this bug is so easily spread and because it’s caused by a virus which means the only treatment is rest and fluids. It’s likely, by coming to hospital, you could infect other people.”

People with the winter vomiting bug should stay off work while the symptoms persist and for about two days afterwards when they’re still infectious.

Practising good hygiene by washing hands regularly reduces the chance of passing on the infection.

“Where possible it’s best to stay isolated while you have the symptoms,” says Dr Patel.

“As distressing as it is, the best thing you can do is rest and drink plenty of water.”