Outbreaks of the "winter vomiting virus" yesterday continued to disrupt services at hospitals in Galway, Kilkenny and Waterford.
The Western Health Board said the outbreak at University College Hospital, Galway, was particularly difficult because 19 suspected cases were spread throughout the hospital. This, combined with the ability of the virus to spread, was a source of serious concern.
A spokeswoman said the health board was appealing to relatives and friends not to visit patients or at least to nominate just one person to visit. She realised this could be difficult and distressing for patients and their families.
With the exception of antenatal and children's outpatient clinics, all planned surgery and procedures and outpatient clinics have been cancelled for the week.
Waterford Regional Hospital has 13 patients in isolation and eight staff off duty because of the virus. All non-urgent orthopaedic surgery has been cancelled.
The South Eastern Health Board said the hospital had been particularly badly hit since the virus appeared in the region early this year. Approximately 250 patients and the same number of staff have been affected in that period.
St Luke's Hospital, Kilkenny, has eight patients in isolation and three staff off duty with the virus. Planned operations are going ahead as normal.
Other health boards said they had no reports of any current outbreaks of the virus, the effects of which last for two or three days.
Meanwhile, the winter vomiting virus has also been affecting holidaymakers on skiing holidays in Andorra.
The most recent instance occurred at the end of March. According to the National Disease Surveillance Centre, a flight from Toulouse touched down at Dublin Airport with some passengers suffering vomiting and diarrhoea.
They had been on a skiing holiday, and about 25 of them had been ill during their stay in Andorra.
At the end of January two flights from Toulouse, one to Dublin and one to Belfast, had landed with passengers suffering from the winter vomiting virus.