The Midland Regional Hospital in Tullamore has been hit by an outbreak of the winter vomiting virus, it was confirmed yesterday.
The bug is currently affecting up to 10 patients in the ear, nose and throat (ENT) section.
The Midland Health Board yesterday appealed to people to co-operate in trying to prevent the bug from spreading.
The virus was first detected among a very small number of patients in a medical ward in the hospital over a week ago and it was believed it had cleared up. But it resurfaced at the weekend in the ENT area.
Affected patients have been isolated and elective admissions to the ENT unit have been postponed. Winter vomiting disease is caused by viruses known as Small Round Structured Viruses (SRSV) or Norwalk-like Viruses (NLVs).
They usually cause short-lasting outbreaks but can be extremely infectious.
Contaminated oysters and water are important sources of transmission and symptoms include nausea, vomiting, diarrhoea, and abdominal pain. Headache and low-grade fever are also common. The illness usually lasts no longer than 48 to 72 hours.
In a statement, the health board yesterday asked for co-operation from the public.
"If you or a member of your household have experienced nausea, vomiting and/or diarrhoea within the last 48 hours please do not visit the hospital as you risk spreading the virus to sick, vulnerable patients, some of whom are on treatment for serious illnesses," it said.
"Visitors are asked to please obey directives and instructions from staff. Visitors are not allowed to visit the isolated areas in the hospital. This is a highly infectious virus and can be potentially dangerous in the very young or old," it added.
Furthermore, it said if patients due for admission or their family members were displaying symptoms they should inform the hospital before their admission date.
Meanwhile, in a separate development, it has emerged that non-urgent elective admissions to the three hospitals in the Midland region in Tullamore, Portlaoise and Mullingar have been curtailed from now to the end of the year. The decision was taken by the health board because it had already met and exceeded the amount of elective work set out in its service plan, and it will only be funded for its targets.
A report circulated to board members said that at the end of October, the board was some 5 per cent ahead of its in-patient activity target and 10 per cent in excess of its day case target.