Two Northern Ireland hospitals have been hit by a vomiting and diarrhoea bug — with one being forced to close down a ward.
Heightened infection controls have been brought in on an elderly ward at the Altnagelvin Hospital in Londonderry, which has been closed to new admissions.
The closure comes as a small number of patients and staff at Belfast's Royal Victoria Hospital were also hit by vomiting and diarrhoea.
No wards have been closed at the RVH but visitors are being restricted.
The outbreak comes at a time when hospitals across the province are already under strain.
In Derry, visitors who are themselves feeling ill have been warned to steer clear of the wards.
The Western Health and Social Care Trust, which closed the ward on Friday, issued a statement a calling for public co-operation.
A spokeswoman confirmed last night that the ward remains closed.
The trust's Infection Prevention and Control team was monitoring the situation over the weekend.
Staff said increased infection control measures have been taken.
Western Trust Chief Executive, Elaine Way, said: “Diarrhoea and vomiting is easily spread in closed environments and the decision was taken to close one ward to admissions as part of infection control measures.
“The public has an important role to play by not visiting the hospital if they are feeling unwell, particularly if they have diarrhoea and/or vomiting.
“And if someone has been unwell we advise them to wait until at least 48 hours after they have had symptoms before visiting.”
Ms Way added: “Those who are visiting are asked to thoroughly wash their hands before and after visiting, for their own protection and for the patients.
“The public are asked to limit visiting to the designated times of between 3pm and 4pm and from 7pm until 8.30pm.
“They should only visit one patient whilst at the hospital and should not move from ward to ward when visiting.”
Trust staff said the situation will be kept under review with a view to reopening the ward affected to patient admissions “as soon as is possible”.
In Belfast, no wards have been closed at the RVH but visitors were being restricted to two people per bed.
The Belfast Trust said that children should not visit at this time.
The trust said that vigorous infection control measures had been put in place.