AN outbreak of the winter vomiting bug has hit 50 patients at a health trust leading officials to call on the public to help keep the numbers to a minimum.

Officials at County Durham and Darlington NHS Foundation Trust issued an appeal to those who are suffering from sickness or diarrhoea not to visit relatives in hospital until they have been free of symptoms for at least 48 hours.

This follows an outbreak of suspected norovirus across two of its sites - Darlington Memorial Hospital and the University Hospital of North Durham - as well as wards at some of its smaller community hospitals.

Trust officials are also asking that elderly people and young children should not visit relatives or friends in hospital for the time being.

Robin Mitchell, medical director for County Durham and Darlington NHS Foundation Trust, said: "Cases of diarrhoea and vomiting traditionally go up in the colder months, however, this year levels in the North-East are already especially high.

"The Trust has 50 patients affected across five wards with suspected norovirus.

"We have procedures in place to manage patients with such symptoms which includes isolating them, making sure staff aren't moving around and increasing cleaning and reinforcing infection control practice."

Most bouts of winter vomiting are caused by norovirus infection, which is the most common cause of gastro-enteritis in England and Wales. It is estimated that norovirus affects between 600,000 and one million people in the UK every year.

Noroviruses cause a very unpleasant, but generally short-lived, illness from which people will usually recover without treatment. The main symptom is vomiting, which can be projectile in nature, and is sometimes accompanied by diarrhoea. Some people may have a raised temperature, headaches and aching limbs.

Norovirus is highly infectious and it can spread rapidly in semi-closed communities such as hospitals. People feel very unwell when they have a norovirus infection, but it is not usually necessary to seek medical advice unless symptoms persist for more than a few days.

Other NHS hospitals in the region are also advising anyone with symptoms of norovirus not to visit relatives or friends until they have fully recovered.