Tests have been carried out on more than 60 people after an outbreak of the dangerous stomach bug E-coli.

Doctors have been warned to watch for patients displaying symptoms of the bug after seven cases were confirmed in the district. Around 60 people who have come into close contact with the confirmed cases are waiting to find out if they have the illness.

A week ago, Ben Rhydding Pre-school Playgroup at Ilkley was closed after two youngsters were diagnosed with illness, potentially fatal to vulnerable groups such as young children and the elderly.

The playgroup, which looks after about 50 pre-school children in a building on Bolling Road playing fields owned by Ben Rhydding Primary School, remains closed today.

A third child who had been in contact with the children was also confirmed to be suffering from E-coli 0157. One of the children required hospital treatment.

Public health officials are linking all the cases although investigations are still ongoing to find the source of the infection.

One child is currently in hospital in Leeds being treated for symptoms of the disease which can include severe stomach cramps, diarrhoea, vomiting and fever. The youngster's condition is described as stable.

In some people, including the very young and the elderly, the disease can develop into a life-threatening illness with kidney failure, brain damage, strokes, seizures and death. An outbreak of E-coli in Lanarkshire, Scotland, which was associated with cooked meat products, resulted in 18 deaths and made 496 others very ill.

Dr Martin Schweiger, director for the Heath Protection Agency in West Yorkshire, said: "As of today there are seven confirmed cases of E-coli, one of whom is in hospital. Two of the cases are adults. Investigations to identify the source of the infection are continuing. GPs have been alerted to look out for symptoms associated with the illness. Our staff are offering advice to and obtaining samples from anyone who has been in contact with those people affected.

"We are asking those people we have already contacted to heed the instructions they have been given, both for the welfare of their family and the protection of others."

The infection can be spread from person to person and people can be infected by eating contaminated foods. Dr Suzanna Mathew, consultant in communicable disease control with Bradford Health Protection Team, said: "Gastrointestinal infections can be prevented by ensuring thorough handwashing, especially when preparing food and after using the toilet, including nappy changing and after contact with animals."