Dr Malcom Bell, director of Technopath, a food and water hygiene firm, said that despite the high profile of cryptosporidium, only two strands of the bug are problematic for humans.

Speaking to the National Water Summit, in Croke Park, the Sunday Business Post reports that he said: “There is a lack of knowledge about the fact that only two of the 30 strains of crypto are harmful to humans.”

He added: “Most outbreaks that result in boil notices are the result of sewage overflowing back into water supply systems. The heavy rain of recent times is compounding the problem.”

At the same event, Ronan Daly, senior water consulting engineer with Atkins, suggested making grants available to households to replace old lead pipes.

“It would also benefit water conservation, because lead leads to leakage in the piping system,” he said.

Earlier this month, the Environmental Protection agency warned that lead contamination had been discovered in 23 of the nation’s water supplies.

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