Health officials in Vancouver are hoping a virus common during the winter months will spare the city next month, when thousands of athletes and spectators from around the world will gather for the Winter Olympics.

The bug is the Norwalk virus, known officially as norovirus, which causes nausea and vomiting among other things. It's rarely fatal, but can leave stricken individuals bedridden for up to three days.

"Norovirus is highly communicable, it's common, and the winter Olympics take place during the norovirus season," said Dr. Reka Gustafson, director of communicable disease control in Vancouver.

Vancouver public health says the bug is already making people sick in British Columbia.

Norwalk is spread through person-to-person contact or through infected food. And as Olympic venues fill with spectators in February, they will become ideal sites through which the bug can spread.

On top of infecting fans, the worry is that athletes competing for gold could become sick, forcing them out of the elite competition.

As precautionary measures, local health officials plan to install extra hand-washing facilities, increase the number of food site inspections, and post public health nurses to medical clinics that will serve athletes and Olympic workers.

"If there is someone who's presenting with vomiting and diarrhea, there will be immediate public health follow-up," Gustafson said.

Those suspected of carrying the virus may be asked to isolate themselves while authorities track down anyone who may have been exposed to infected individuals, in the event of an outbreak.

A number of cities across Canada are already reporting outbreaks in local hospitals, nursing homes, daycares and schools.

"It seems to be on its annual worldwide tour," said Dr. Neil Rau, an infectious diseases consultant and medical microbiologist.

"It will take your usual day-to-day activities and make them impossible for you," while your ill with the virus, Rau said.

Toronto public health says it has 25 suspected or confirmed cases of the virus.

Cambridge Memorial Hospital, an hour west of Toronto, is one of many Canadian health-care centres coping with Norwalk's effects.

Last week, visits to the general medicine unit were restricted after patients and staff came down with the contagious virus.

"Our community, I think, is pretty much like any other one," said Dr. Michael Lawrie, interim chief of staff at the hospital. "This is just the bug of the day right now."

"We had to do what's called a ‘lock-down' on our medical ward, where weren't admitting other patients," he added.

With extensive cleaning and hand-washing, officials at CMH say they have tamed the outbreak, reducing the number of active cases to two.

- With a report from CTV's Avis Favaro and producer Elizabeth St. Philip