Animal faeces or carcass likely cause of water contamination scare

The water contamination incident affecting more than 300,000 households in Lancashire could lead to criminal prosecutions according to a government watchdog, as experts said animal faeces or a dead carcass was most likely to blame.

Investigations are continuing into how traces of the Cryptosporidium bug found its way into a water treatment plant near Garstang, run by United Utilities.

The Drinking Water Inspectorate said it could not comment on the source of the outbreak while the investigation was ongoing but that it had powers to bring criminal charges against water companies. Dŵr Cymru Welsh Water was fined £60,000, plus £70,000 costs, in 2005 after an outbreak of cryptosporidiosis in North Wales infected 231 people.

The water company, which is still finding traces of the parasite in its supplies, has said that animal waste was the most probable cause and has confirmed that it will not lift restrictions in place since last Thursday until it is confident that there are no traces left in the water network.

Cryptosporidium is a parasite found in livestock and people that can cause diarrhoea, vomiting and nausea. Traces of the bug were discovered during routine testing at the Franklaw water treatment works, in Lancashire, on 6 August. United Utilities confirmed that testing for the bug takes place at the site every two days.

As yet there have been no confirmed cases of illness, but a spokesperson for Public Health England said they might expect some cases in the next few days, with the average incubation period about seven days. Young and elderly people as well as those with compromised immune systems, such as HIV sufferers, are most at risk.

In 2008, Anglian Water was heavily criticised for basic hygiene failings after a rabbit entered one of its water tanks leading to an outbreak of cryptosporidiosis, with 22 people falling ill.

Dr Derek Gatherer, an expert in diseases and viruses at Lancaster University, said an animal was the most likely source of the outbreak.

“Human strains are often spread from person to person, but in cases of water contamination it tends to be animal faeces or a carcass that gets into the supply. How likely a sheep or cow would get stuck in the water system I don’t know, but they will be able to confirm the source once they get results back [from the Cryptosporidium reference unit in Swansea].

Although there are about 3-5,000 cases of Cryptosporidium a year in humans in England and Wales, there have only been two examples linked to water supplies since 2000. The first was the outbreak in Wales in 2005 and the second the 2008 outbreak in Northamptonshire.

“We’re getting into the time when we’d expect to start seeing confirmed cases of the infection cryptosporidiosis, so if we don’t get any over the next few days then we’ve probably got off,” added Gatherer.

United Utilities has said that it would be contacting residents offering them compensation once restrictions had been lifted.