SEVERAL wards at North Yorkshire's biggest hospital have been closed after an outbreak of sickness and diarrhoea among patients.

The virus, combined with a rise in the number of patients needing emergency treatment, has resulted in an increase in demand for services at York District Hospital.

The virus, a Norwalk-type infection, was said to be typical at hospitals and is thought to have been brought in by a patient, a member of staff or a visitor.

Director of nursing Mike Proctor said staff were working to ensure patients receive the usual level of care.

The outbreak is the third in four months at York District Hospital.

In December, five wards were closed due to a similar virus and in November, seven wards and 200 patients were affected in a spate of sickness and diarrhoea cases.

Mr Proctor said: "Not only would we like to praise the commitment and dedication of all our hospital staff during this difficult period, but we would also like to thank our patients, their families and friends for bearing with us."

Hospital chiefs are now trying to contain the virus.

The illness is easily spread from person to person, but the symptoms usually ease within 24 hours.

Mr Proctor said patients should wait 48 hours after symptoms disappeared before coming into contact with anyone vulnerable to infection.

He said: "We are urging anyone affected to refrain from visiting hospitals until at least two days after symptoms have ceased."