At least one death in Ireland has been linked to cryptosporidium contamination in public water supplies in the last five years, it has emerged.
It comes as one of the most senior public health experts in the State warned that the mortality rate from the infection was as high as one in every 200 cases.
The Irish Times has established that cryptosporidium is listed on the death certificate of at least one individual who died in the midlands region during a cryptosporidium outbreak in the summer of 2002 caused by contaminated drinking water sourced from Lough Owell near Mullingar.
Cryptosporidium infection is identified as one of three causes of death on the death certificate of the individual, a copy of which has been seen by this paper. The person had also been suffering from cancer combined with a viral infection.
Those suffering from cancer often suffer from a weakened immune system, which in turn makes cryptosporidium infection potentially lethal.
Despite the fact that cryptosporidium is a notifiable infection, the Department of Health was unable to state whether there had been any deaths linked to the infection, in a Dáil reply on Wednesday evening to Westmeath TD Paul McGrath.
He called for mandatory testing for cryptosporidium, which is a microscopic parasite. At present drinking water is only tested if contamination is suspected.
He said the death in 2002 showed "the gravity of the situation facing Galway".
A new treatment plant capable of tackling the cryptosporidium problem in the midlands will not be operational until 2005.
Dr Paul McKeown, consultant in public health medicine at the Health Protection Surveillance Centre, said those with weakened immune systems and children under five were particularly vulnerable if infected.
Data released by the Environmental Protection Agency showed that 80 public water supplies throughout the State were identified as being at high or very high risk of contamination with the parasite.