SCIENTISTS HAVE discovered a potentially lethal strain of E.coli in Irish beaches, rivers and lakes previously deemed to have excellent water quality under European Union standards.
The bacteria, known as Shiga-toxigenic E.coli (STEC), was found by academics from the School of Medicine in NUI Galway at several popular bathing spots across Ireland.
STEC infections have been linked with several diseases and, in serious cases, can lead to severe intestinal infection, potentially renal failure and even death.
Ireland has 10 times the number of STEC infections compared with the EU average.
The study saw academics test water samples from the sea, rivers and lakes dating from December 2018 through to October 2019.
Each of the 75 sites tested were used for bathing or recreation of some kind.
Alarmingly, 49 (65%) of the sites analysed tested positive for STEC.
More than nine in 10 (93%) of samples taken from rivers in Ireland tested positive, while the disease-causing bacteria was also found in three quarters (75%) of lake samples and over half (56%) of seawater samples.
“There was a high occurrence of genetic markers for STEC in the samples tested, highlighting the need for further investigation to establish the scale of the problem, not only in Ireland but globally,” Prof Dearbháile Morris, who co-authored the study, told The Irish Times.
“It is worth noting that all of the bathing waters tested were designated as of good or excellent quality based on current EU bathing water quality monitoring criteria.”
Professor Morris was keen to note that while most E. coli are not harmful, some like STEC can be poisonous.
He also noted that bathing waters in Europe are not routinely monitors for the presence of STEC.
“This study highlights the limitations of only assessing the total number of E. coli present as an indicator of water quality without taking into consideration the potential pathogenicity of some variants,” he concluded.