SIX wards at York hospital have been closed to new patients because of a sickness bug sweeping the building.

Staff at the Wigginton Road site closed the wards after some of its patients came down with a highly contagious vomiting bug.

Two more wards have also been partly closed because of sickness.

Levels of the infection rose rapidly yesterday as the number of wards which had to be shut trebled.

The affected areas, which include elderly and general medical wards, are closed to new patients being admitted.

Existing patients are being discouraged from having large numbers of visitors in an attempt to control the spread of the bug.

Hospital chairman Alan Maynard said: "Diarrhoea and vomiting seems to be increasing both out in the community, in schools and old people's homes as well as in hospital.

"This is really a hell of a challenge to keep the patients flowing through and to protect them - it's very difficult."

Professor Maynard said relatively few patients actually had the bug - yesterday morning it was fewer than two dozen. But wards still had to be closed because the bug is airborne and spreads very quickly.

It has not yet been confirmed that the sickness at the hospital is the notorious Norwalk virus which wreaks havoc in community settings like care homes and hospitals every winter.

Tests have to be carried out on affected patients to confirm whether or not they have the virus.

Nursing director Mike Proctor said this year's spread of sickness had started about ten days ago and was being monitored daily.

Over the weekend, three wards were closed, but that dropped to two on Monday.

But by yesterday afternoon, that figure shot up to affect eight wards, with six fully shut.

Mr Proctor said: "We're discouraging lots of extended families coming into to visit people ... and to do it in discussion with the ward sister."

Anyone with any vomiting or diarrhoea symptoms was being advised not to come into hospital, he added.

In February last year, seven wards had to be shut at the hospital when dozens of elderly patients were struck down with a Norwalk-type virus, also known as Norovirus or viral gastroenteritis.

During the same month, both wards at Selby Memorial Hospital had to be closed because of the bug.