Folk in the Blackpool, Preston and Chorley areas will no doubt already be aware of the problem with infection in their water supply.
By and large the Cryptosporidium parasite is just an unpleasant infection however it can be more serious for people like us who are immunocompromised. Those of you in the North West on immunosuppresive drugs should take extra care to boil any drinking water and take the advice being given locally.
There's a link here that you might also find useful :