An outbreak of the food-borne E.coli bug is being investigated in Enniscrone, Co Sligo, after six people became ill with gastroenteritis.
The Health Service Executive West said the six people had suffered from E.coli 0157 infection but are now recovering.
The bug may cause serious illness and complications, particularly among very young and elderly people and those with weakened immune systems and pregnant women.
"There are concerns about a possible association between these infections and people who had been in Enniscrone, Co Sligo between July 20th and August 20th, 2007," the HSE said in a statement.
It added, however, that it is in the early stages of the investigation and that no conclusive findings have been made at this time.
As a precautionary measure, the HSE said it would like to identify members of the public who visited, stayed in or ate food in Enniscrone between July 20 thand August 20 thand who subsequently became ill with diarrhoea, vomiting or abdominal pain.
Anyone who suffered such illness should contact the HSE helpline at 1890 200 548.