Norovirus hits Royal Glamorgan Hospital in Llantrisant
The Royal Glamorgan Hospital in Llantrisant has become the latest in Wales to be hit by the winter vomiting bug norovirus.
Cwm Taf Health Board said several wards had been affected and were temporarily closed.
It is urging members of the public to minimise visits to the hospital.
The bug has also closed wards at Withybush Hospital in Haverfordwest, Bronglais Hospital in Aberystwyth and at five hospitals in north Wales.
Cwm Taf Health Board said: "Several wards have been affected and are temporarily closed.
"Measures are in place to minimise the risk to patients."
It said the bug - which causes vomiting, stomach cramps, fever and diarrhoea - is easily spread from person to person.
Symptoms usually begin between 12 to 48 hours after a person becomes infected with most healthy people making a recovery within one to three days.
"The illness is generally not severe but hospital patients with weakened immune systems may be more vulnerable and action must be taken to prevent spread," it added.
Visitors with symptoms are being told to stay away from hospital.
They are also asked not to bring babies and young children into the affected wards.
The bug has also hit Ysbyty Gwynedd, Wrexham Maelor, Glan Clwyd, Colwyn Bay, and Tywyn in north Wales, as well as Withybush and Bronglais this week.
The chief medical officer for Wales, Dr Tony Jewell, says anyone with norovirus should not turn up at hospital emergency departments for treatment unless advised to, and not to visit anyone in hospital.