Why doctors say we need to cast a wider net for COVID-19 in Canada | CBC News

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Canada’s first case of coronavirus not linked to travel suggests we need to expand our surveillance systems to prevent an explosion of new cases, infectious disease experts say.

The latest case of COVID-19 in British Columbia, a woman in her 50s who has no recent travel history to affected regions worldwide or contact with infected individuals, signals a shift in the spread of the virus in Canada. 

“There’s likely at least one other person out there who has this disease or had this disease, and we need to find them,” B.C. provincial health officer Dr. Bonnie Henry said Thursday.

Dr. Isaac Bogoch, an infectious disease physician at Toronto General Hospital, said this means there could be more cases in the province that are likely being missed by current screening measures. 

“There is some degree of transmission in B.C.,” he said. “We don’t know the size and scale of it, but it’s definitely there and the goal for surveillance systems would be to help shed light on what the degree of community transmission is.” 

Bogoch said Friday that while it’s been important to have systems in place to screen for patients travelling from affected regions, the concern now is how sensitive those systems are at picking up new cases in the community. 

“Clearly something is happening under the radar of the surveillance system,” he said. 

“It doesn’t mean the surveillance system is bad, it just means that there might be low levels of transmission or the surveillance system has not cast a wide enough net yet.” 

Currently, most health-care workers in Canada are screening only people who show up with flu-like symptoms such as fever and dry cough and say they’ve travelled to an