Dan GrimmerVisitors are banned from the Norfolk and Norwich University Hospital for two days as staff struggle to contain an outbreak of the winter vomiting bug.Norovirus has hit 15 patients across eight wards in the past 48 hours and managers said wards will not be open to visitors until at least tomorrow .Dan Grimmer

Visitors are banned from the Norfolk and Norwich University Hospital for two days as staff struggle to contain an outbreak of the winter vomiting bug.

Norovirus has hit 15 patients across eight wards in the past 48 hours and managers said wards will not be open to visitors until at least tomorrow .

Unless absolutely necessary visitors should not go to the hospital but patients should still attend their hospital appointments.The Norovirus stomach bug causes nausea and diarrhoea and is very easily spread from person to person. The spread of infection is easiest in places where group of people are in close proximity for reasonable amounts of time such as residential homes, schools, hospitals and workplaces.

The virus lasts about two days and no treatment is required. However, even after the symptoms have cleared up people may still carry the virus and infect others up to three days after their own symptoms have stopped.

Dr Judith Richards, director of infection prevention and control at the N&N, said: 'We want to protect our patients by restricting the chances of people spreading this infection.

'For this reason, regrettably, we are asking that people do not visit, unless absolutely necessary. It's very important that people who have had the virus, or been in contact with someone who has had it, take precautions to avoid spreading it. That means not going back to work or school until two days after the symptoms have stopped.'

Noroviruses are a group of viruses that are the most common cause of gastroenteritis or stomach bugs in England and Wales, affecting up to one million people a year and often referred to as winter vomiting bugs.

It is easily transmitted from one person to another - it can be transmitted by contact with infected person, by consuming contaminated food or water or by contact with contaminated surfaces or objects.

The symptoms of norovirus infection will begin about 12 to 48 hours after becoming infected. The illness is self-limiting and the symptoms will last for 12 to 60 hours.

They will start with the sudden onset of nausea followed by projectile vomiting, and watery diarrhoea. Some people may have a raised temperature, headaches and aching limbs.

Most people make a full recovery within one to two days, however some people (usually the very young or elderly) may become very dehydrated and require hospital treatment.

Good hygiene is important in preventing others from becoming infected - this includes thorough hand washing before and after contact. Food preparation should also be avoided until three days after symptoms have gone altogether.