Members of the public have been asked not to visit Nenagh General Hospital after an outbreak of the winter vomiting bug.
A spokesman for the hospital said there were 13 cases of the bug this morning, a reduction of five on yesterday.
"We have a microbiologist monitoring the situation from Limerick," the spokesman said.
He said the bug first emerged on Wednesday, is found in a range of age groups, and is not confined to one ward.
Normal precautions have been put in place, and admissions have been restricted.
A HSE spokesman said: "Emergency cases will be stabilised where required before transfer to other hospitals in the region. Infection control procedures have been intensified and every effort is being made to discharge any patients deemed medically fit."
