Incidences of a water-borne bug that can cause serious illness or death have doubled in the last year, according to the Environmental Protection Agency.
Some 535 cases of Verotoxigenic E.coli (VTEC) contamination were reported in Irish water supplies in the year up to November 21st. The equivalent figure last year was 251.
The bug can cause severe bloody diarrhoea and abdominal cramp but in the very young and old it can cause haemolytic uraemic syndrome. According to the HSE, up to 9 per cent of all patients who develop the syndrome die. It can cause kidney failure and, in some cases, permanent kidney damage. An outbreak in northern Germany caused more than 200 cases of the syndrome and two deaths.
The rise in cases has been blamed on better detection but also on the heavy rains in the first half of the year. In July the HSE reported that two private supplies had been contaminated with VTEC. The excess rainfall led to flooding which washed toxins into the water supply leading to contamination.
The outbreaks were mostly confined to private water supplies. Public water supplies, which are used by 80 per cent of the population, benefit from better water treatment.
The results were published in the agency’s annual report into the provision and quality of drinking water in Ireland.
The safety of Irish public water supplies overall continues to improve, the agency said.
In 2011 E.coli was detected in 12 (1.3 per cent) of public water supplies. In 2010 it was 20. The equivalent figure in 2004 was 91. The reduction has been in the order of 86 per cent in the last six years.
The improvement has been credited to the security of disinfection systems including, for the first time, the provision of chlorine monitors and alarms at all public water supplies. However more than one in 10 private group schemes had an E.coli infection last year. The detections in 2011 were 46 (10.2 per cent) down from 56 (11.6 per cent) in 2010.