Hospital wards and care homes have been forced to close to new admissions after an outbreak of norovirus in Swansea.
Swansea Bay University Health Board said 75 people have had symptoms of the bug in the past fortnight, with a number confirmed as norovirus.
Wards at Morriston Hosptial, Singleton Hosptial and Neath Port Talbot Hospital have all be closed to new admissions.
Staff have urged people showing symptoms to stay away from hospitals and other communal areas.
The virus has shut the whole of Gorseinon Hospital, while wards C and D at Neath Port Talbot Hospital, ward B (trauma and orthopaedic) at Morriston and ward 12 at Singleton Hospital all have confirmed cases of norovirus and have been closed to new admissions.
Two care homes are also not taking anyone else in.
Joanne Walters, the infection, prevention and control matron for the health board, said: "This is the norovirus season traditionally so we would expect to see it circulating.
"We just need people to be aware that they don't need to present themselves to hospital if they have this virus."
The virus, which spreads easily from person to person, causes vomiting, diarrhoea and nausea and cannot be cured with antibiotics.