A woman in B.C. has tested positive for COVID-19 despite not having travelled recently and having no known contact with anyone infected with the virus.

Until now, all cases in Canada involved individuals who had recently travelled to countries such as Iran, Italy, Egypt and China or who had close contact with those travellers.

The new case, considered Canada’s first community case, marks the first time that health officials haven’t been able to pinpoint the source of a patient’s infection. “We need to find out the source of her infection. So I expect that we’ll see other people turn positive because of that,” Henry said at a press conference Thursday.

A community outbreak is when the virus moves beyond initial travel-related transmission and begins to spread freely from person to person. A community outbreak has not been confirmed in Canada, but the first community case suggests that there may be others out there who don’t know they have the virus.
To make matters even trickier, COVID-19 can be difficult to detect, particularly at its onset. About 80 per cent of all cases worldwide are considered mild.

Half of all of Canada’s 46 COVID-19 cases are in Ontario. So far, no community cases have been reported in Ontario — but those can be tricky to detect, according to Dr. Susy Hota, University Health Network medical director of infection prevention and control.