A ward has been closed at Inverness’s Raigmore Hospital just hours after it reopened after patients displayed symptoms of norovirus.
Ward 5C has been shut to new admissions as a precautionary measure after two patients suffered vomiting and diarrhoea.
Infection control staff are now waiting for test results to come through before their next move.
The ward only reopened on Wednesday after two separate patients were found not to have norovirus.
However means that there now three wards shut at the hospital because of the ongoing outbreak.
Ward 2C and Ward 7C remain closed to new admissions.
Ward 2C has 17 patients affected and Ward 7C now has 10 patients affected. Testing has confirmed norovirus is present on both wards.
The virus, which causes diarrhoea, nausea and vomiting, spreads in the air where someone has had diarrhoea or vomited and is extremely infectious. It is important that everyone plays their part in reducing outbreak risks.
Visiting to all three wards is currently restricted and health bosses have repeated warnings to the public not to visit unless by prior arrangement with staff.
A spokeswoman said: “Hospital staff will of course be very happy to talk to visitors on the phone so they can get updates on how their relatives are.”
It is hoped that the hospital will be back to normal by next week.
Patients must be free of symptoms for 48hours before deep cleaning of the ward can be carried out.
Dr Ken McDonald said that if outbreaks are not contained quickly, there is a danger of it “spreading rapidly through the hospital”.
He added: “We have not had to cancel surgery and have been able to continue with our emergency admissions process.”
He said: “It is difficult to prevent the virus entering hospital in first place. It is almost impossible to do that.
“Some people will become unwell with the virus in the community and then be admitted for that or other reasons.
“The key thing is identifying it early.”