How Nova Scotia investigates community spread of COVID-19

Amid Nova Scotia's first possible case of COVID-19 contracted by community spread, Nova Scotia's top health official gave a bit of insight Thursday into how the province will be investigating cases like this.

"It's very much like detective work," Dr. Robert Strang, Nova Scotia's chief medical officer of health, said at a Thursday press conference.

Of the 73 confirmed cases in Nova Scotia as of Thursday, only one hasn't been connected to travel or a previous case. It might be tied to a St. Patrick's Day dance held at the Lake Echo Community Centre on March 14, which is before there were any cases reported in Nova Scotia.

Strang said one of the first steps of the investigation is the public health nurse talks to the person who has contracted the virus and asks where they were during a certain time frame, what they were doing and who they were in contact with.

"And then we approach it by layers and reach out to those contacts. It's all about ... shoe-leather epidemiology, it is getting out, talking to people," Strang said.

Close contacts get tested

Strang said anyone who has been defined as being in close contact with someone who was diagnosed with COVID-19 will be tested.

"We're putting them in self-isolation, but we're not waiting to see if they get sick or not," Strang said.

He said officials are in the midst of speaking with people who were at the St. Patrick's Day dance and they're trying to be discreet.

"As much as possible, we work quietly to talk to contacts, make sure people are aware they have been exposed and the appropriate steps are taken," Strang said.

He said measures the province has taken to date should minimize community spread, but he still expects it to happen in Nova Scotia, as it has in many Canadian provinces.

The province makes public announcements about places and times of potential public exposure. So far, they've done this twice. The examples are a Halifax basketball tournament and the St. Patrick's Day dance.

"We only use that when our other methods, our more private approach ... won't get us to where we need to be," Strang said.

Whether Nova Scotia is considering looking at smartphone data to help track down COVID-19 cases is unclear.

"I know some folks are, you know, around the world are looking at that cellphone data," Strang said. "We're looking at that, we're not we're not able to, ready to use that yet."

However, in an email to CBC News, government spokesperson Marla MacInnis said "the province is not considering this."

On Tuesday, Prime Minister Justin Trudeau said he hadn't ruled out using that data to track whether people are complying with orders to stay inside.

In places like Italy, Germany and Austria, telecommunications companies are sharing aggregate smartphone data with health authorities to monitor whether people are complying with self-isolation demands.

China, Taiwan and South Korea are using smartphone location pings to trace people who tested positive or to enforce quarantine orders.