Twelve children are at the centre of an outbreak of illness caused by the cryptosporidium parasite in Perthshire.

Tayside Health Board said eight children were confirmed to be suffering from the illness, while four further suspected cases have been reported.

An investigation has been launched into the cause of the outbreak, with suspicion centring on a Perth swimming pool.

The cases came to light after more than 150,000 people in parts of Glasgow and Clydebank received the all-clear to use their tap water.

Cryptosporidium can cause illness

They had been advised to boil water before using it after concern was raised over the levels of cryptosporidium in water supplies.

Tayside NHS Board said that all those involved in the outbreak in the east of the country were being treated at home.

The 12 youngsters affected were not said to be seriously ill.

At least five of the children had visited Perth Leisure Pool on different occasions since mid July 2002.

Investigators have yet to speak to the parents of the other three children confirmed with cryptosporidiosis.

Pool closed

As a precaution Perth and Kinross Leisure, which runs the pool on behalf of Perth and Kinross Council, has closed the facility pending tests.

Executive manager Peter Bing said: "We had no hesitation in following the advice of the outbreak control team to close the leisure pool to allow a full investigation to take place.

Peter Bing: "Full investigation"

"We regret the inconvenience to the many people who use the pool every week, but public safety will always be our number one priority."

Cryptosporidium can cause severe diarrhoea, sickness, stomach cramps and a slight fever.

An outbreak control team has been set up with representatives of Tayside NHS Board, Perth and Kinross Leisure, Perth and Kinross Council and Scottish Water.

Chairwoman Dr Julie Cavanagh, public health consultant at NHS Tayside, said: "It is very important to stress that the problem we are dealing with in Perth is completely different to the situation in Glasgow where cryptosporidium affected the public water supply.

"We do not believe the issue we have in Perth is related to the public water supply.

Medical advice

"Although our investigations are at an early stage, we believe it is likely the outbreak has been caused by the accidental faecal contamination of one of the pools used by children within the leisure complex."

She said it was believed that only a small number of people were affected.

"If anyone who has used the pool within the past four weeks has a continuing stomach upset, our advice is to take plenty of fluids, observe good personal hygiene and seek the advice of your doctor," added Dr Cavanagh.

Dr Drew Walker: "Mild illness"

NHS Tayside's director of public health, Dr Drew Walker, said: "Cryptosporidiosis is usually a mild illness which in healthy individuals may pass unnoticed.

"It is most frequently seen in young children and may pose a risk to people who are frail or susceptible to infection.

"Perth and Kinross Leisure has acted quickly and responsibly on the advice of the outbreak control team.

He expected that the pool would reopen "as soon as we are satisfied the facility poses no significant risk to public health".