The number of cases of the so-called winter vomiting bug in at least two Killarney hotels is falling, the Southern Health Board said yesterday.
Some 36 cases of the gastro-intestinal illness have been reported since Wednesday of last week, with four new cases on Monday, one on Tuesday and one more yesterday.
The health board's outbreak control team of area medical officers, environmental health officers and specialists in public health medicine are investigating.
"While no organism had yet been identified, the virus responsible for winter vomiting disease is strongly suspected," said a spokeswoman for the health board. Symptoms include nausea, vomiting, stomach cramps and diarrhoea, and the disease is highly infectious and spreads easily.
The health board advises strict personal hygiene and not handling food until fully recovered from the illness.
Hotel staff who have been affected have been asked not to return to work until 48 hours after recovering.
The virus, causes short-lasting but extremely infectious outbreaks. Illness is usually mild, lasting two to three days. As well as person-to-person contact, the virus may also be spread through drinking contaminated water.