HEALTH officials have issued a warning over a sudden increase in cases of a stomach bug.

The cryptosporidium infection causes diarrhoea and abdominal pains and its cause has left experts baffled.

Usually about ten or so cases would be expected in the Harrogate area of North Yorkshire in the first three months of the year - but so far there have been more than three times that number.

People in the area are now being warned to take precautions to minimise the chances of picking up the bug.

Possible causes include direct contact with farm animals or sick pets; consuming unwashed raw vegetables or drinking untreated surface water.

Swimming pools and drinking water may also be a potential risk.

However, initial investigations have shown no evidence to suggest that the mains drinking water in the area is the cause of the increased number of cases.

Swimming pools have also been virtually ruled out following tests taken by local environmental health officials - although their managers and child-care establishments have been contacted to reinforce existing hygiene precautions.

But although each case is being carefully examined to identify any possible links with the risk factors, the experts admit it may not be possible to identify a definite cause.

The unusually warm weather for the past two months may have been a factor and organisations throughout the area are being urged to take precautionary steps to eliminate any possible causes.

The Health Protection Unit has written to all GPs in the Harrogate area alerting them to the increase and asking them to report any suspected cases.

The unit's consultant in communicable disease control, Dr Ebere Okereke, said: "We are all working together to ensure that every possible precautionary measure is taken to avoid further causes of cryptosporidium."

He also reminded people that taking the basic step of maintaining good hygiene helped to prevent the spread of such illnesses.

They include: washing hands after visiting the toilet and before meals, washing fruit and vegetables which are to be eaten raw, not drinking untreated water and avoiding swimming pools or spas if you have symptoms of diarrhoea.

Children should be discouraged from petting and feeding farm animals, babies should wear a swimming nappy when visiting swimming pools.

People who work in the food industry or child-care establishments are also advised not go back to work until 48 hours after gastro-enteritis symptoms have been resolved