FRIMLEY Park Hospital has had to turn away emergency patients and postpone operations as it struggles to contain a virulent bug.
At one stage nearly 100 patients and staff were struck with bug which causes vomiting and diarrhoea.
Staff now believe the virus, which struck the main G4 medical ward, is under control. But its effects are still being felt over the busy Christmas period, which traditionally sees a high number of emergency admissions.
Many of those have had to be transferred to other hospitals in Surrey and Hampshire to ease the pressure on Frimley Park.Surrey Ambulance Service has put extra vehicles on standby in case patients have to be transferred.
Frimley Park admitted it does not know how the outbreak started. Spokesman David Price said it was possible a patient who already had the bug brought it in.
He said the outbreak was difficult to contain because it was affecting both patients and staff.
Mr Price played down the seriousness of the outbreak, saying that the symptoms were similar to gastric flu.
"It's just one of those things. It's been well recorded and written up in medical journals as something that happens every winter in most hospitals and it's in the community," he said.
He added that at its height last Thursday the virus ahd affected 84 patients and a "significant number" of staff.
"Most have now recovered and only eight patients and three staff are currently unwell with the virus," he said.
The virus passes from person to person and causes vomiting and diarrhoea lasting about 24 hours. Mr Price said patients were being given "supportive care to restore fluids". "Elderly patients are particularly vulnerable and it usually takes them longer to recover," he added.
The hospital has been trying to contain the bug by not moving patients with the virus to other wards or to other hospitals. Mr Price added: "In line with national guidelines, the hospital insists on rigorous hand washing which is essential to control the spread of infection."
G4 ward is split into a number of bays and the spokesman said this helped to contain the virus. "It means that we can get a bay clear and disinfect it and make it available to patients," he explained.
Frimley Park has also told Surrey's emergency care management system - run by Surrey Ambulance Service - about the outbreak.This has meant the hospital is accepting fewer patients into accident and emergency and most emergency cases have been diverted to surrounding hospitals.
Mr Price said: "Obviously we have explained the situation we are in and they give us as many emergency patients that we can cope with and the other hospitals then take the others."
Planned operations have also had to be "rescheduled" to prevent the spread of the virus and because the outbreak has placed pressure on ward beds.
He said it was difficult to say exactly how many beds had been closed by the virus because the figure changed "almost from hour to hour". But he said the outbreak was being contained.
"Most patients have now recovered and only eight patients and three staff are currently unwell with the virus," he said.