Boil your tap water before you drink it, residents in Devon have been told, after 22 cases of a parasitic disease were confirmed. South West Water has detected what it calls “small traces” of a parasite that can cause a diarrhoea-type disease in the drinking supply around the town of Brixham. Bottled water stations are being set up in affected areas, the company added, but has told people in Brixham, Boohay, Kingswear, Roseland and north-east Paignton that they should not drink their tap water unless they boil it. Dozens more cases of upset stomachs are being investigated as the disease appears to be sweeping the area. The parasite, cryptosporidium, can cause the disease cryptosporidiosis, which can be a serious illness in immunocompromised people, but most healthy people who get it can expect to recover fully. It is a predominantly water-borne disease and can be caught by drinking contaminated water. Sarah Bird, consultant in health protection at UK Health Security Agency South West, said: “We advise people in the affected areas to follow the advice from South West Water and boil their drinking water and allow it to cool before use. “Anyone with a diarrhoeal illness should drink plenty of water to prevent dehydration and if they have severe symptoms like bloody diarrhoea, they should contact NHS 111 or their GP surgery.” The symptoms of the disease include watery diarrhoea, stomach pains, dehydration, weight loss and fever, which can last for two to three weeks. Bird added: “For most people, cryptosporidium symptoms can be managed at home without needing medical advice. Those affected should stay off school and work for 48 hours since the last episode of illness and away from swimming pools for 14 days after the last episode of illness.” Chris Rockey, the head of water quality at South West Water, told the BBC that people should boil water to drink, cook and clean their teeth with in the affected areas, adding that the firm would continue to work with health professionals and monitor the water. He said he was unable to provide a timeframe for how long the water-boiling would be advised and that an update would be provided when the water supply returned to normal. A spokesperson added: “We are working with public health partners to urgently investigate the source. We apologise for the inconvenience caused and will continue to keep customers and businesses updated. Bottled water stations will be set up in the affected areas as soon as possible.” Customers who have been issued with the notice advising them to boil their water will receive an automatic payment of £15, the company said. The ​Conservative MP for Totnes, Anthony Mangnall, said: “It is enormously frustrating that South West Water weren’t quicker to respond at the first point at when this was reported. “It started with an initial denial that it was anything to do with their network and of course they have now found the cryptosporidium is in their network and they are responding. Residents were quick to actually point out there was something wrong with the water, they could taste it, and now they are suffering.”