Two wards at Bradford Royal Infirmary have been closed to visitors following outbreaks of a winter vomiting bug.

One ward which was previously closed has now reopened and another at St Luke's hospital reopened yesterday afternoon.

Nine schools have also been affected, and health experts have warned the parents of children suffering from symptoms of the norovirus bug, which causes vomiting and diarrhoea, to keep them away from school in a bid to stop the gastrointestinal disease spreading.

Visitors to hospitals and nursing homes have also been urged to follow good hygiene measures.

West Yorkshire Health Protection Unit said it was impossible to say how many people had been affected in Bradford, but said it had reports of suspected outbreaks from schools, hospitals and nursing homes across the district.

Dr Martin Schweiger, consultant in communicable disease control, said: "Norovirus is easily transmitted from one person to another."

A spokesman for Bradford Teaching Hospitals NHS Foundation Trust, said: "We have measures in place to combat this infection but ask for support from people to help prevent it spreading.

"Anyone who wishes to visit should not come in if they have any symptoms or have had symptoms in the previous 48 hours. Visitors should also remember to use the alcohol gel provided at ward and department entrances."

A spokesman for Airedale Hospital said there had not been any reported outbreaks.

A Council spokesman said restrictions were in place at St Oswalds Primary in Great Horton, Margaret MacMillan Primary in Manningham, Frizinghall Primary school, St Matthew's Catholic Primary in Allerton and Bowling Park Primary, Keighley Community Nursery, Midland Road Nursery in Manningham, St Anthony's Catholic Primary in Clayton and Lapage Primary in Barkerend Road.

Helen Metcalf, acting head teacher at Bowling Park Primary, in New Cross Street, said: "We are being extra vigilant. We have sent advice letters to parents and they are being supportive."

The Health Protection Unit said anyone suffering from the symptoms should stay away from school or work until 48 hours after they have stopped, drink plenty of fluids and have plenty of rest to prevent dehydration.