The dining room may reopen by the middle of the week once all residents and employees have been free of symptoms for 72 hours, said Barbara Hood, the chief executive of the parent company Northern California Presbyterian Homes & Services, a nonprofit based in San Francisco.
As of Monday, four residents in the independent-living apartments and two employees had symptoms, and there haven't been any new cases following these six, Ms. Hood said.
"We're about there," she said. "(The residents) can wait a couple of days and we'll be in the clear."
Meanwhile the policy of discouraging visits by outsiders remains in place, Ms. Hood said.
Management closed the dining room Monday, May 16, just ahead of a recommendation to do so by the San Mateo County Public Health Department, Rick Isaacs, the health services administrator, said in an earlier interview.
The Norovirus family of viruses infect the gastrointestinal tract and are easy to pass from one person to another, Mr. Isaacs said. The symptoms — nausea, vomiting and diarrhea — generally go away after three days, during which dehydration is the greatest threat to health. But people can re-infect themselves if they come in further contact with the virus, Mr. Isaacs said.
Residents with symptoms are counseled to stay in their apartments. Staff apply a red dot to the door of affected apartments and disinfect the apartments every day with a diluted chlorine solution, Mr. Isaacs said. Noroviruses are resistant to alcohol-based disinfectants, so the best defense is hand-washing, Mr. Isaacs said.
The kitchen has a supply of disposable dishes and silverware for situations like this and they are treated as hazardous during disposal, Mr. Isaacs said.
No more than a dozen residents have had symptoms at any one time and about six are symptomatic as of May 17, Mr. Isaacs said.
The management has kept the county public health department informed since the first case showed up, Mr. Isaacs said.
Lines of communication would open to the state Department of Public Health if two or more cases were to turn up in the 43-bed nursing home, and to the Department of Social Services if cases came to the 26-bed assisted living facility or the 18-bed memory-care facility, Mr. Isaacs said.
In October of 2003, an e-coli infection took the life of one resident and seriously infected 12 others. The management closed the dining room in that case as well.