TORONTO -- As virus case numbers continue to climb, at least two provinces say they are growing the ranks of contact tracers, a move one infectious diseases specialist says is critical to “block chains of transmission in the community and get the epidemic under control.”

Both B.C. and Ontario say they are hiring 500 more contact tracers. Ontario says by mid-November it will have 4,000 contact tracers on the ground, including redeployed federal and provincial public service staff.

Dr. Isaac Bogoch says it’s important to inform those who have come in close contact with a person infected with COVID-19 that they need to self-isolate for 14 days and get tested if they develop symptoms.

“They are detectives, for lack of a better word. They are really trying to piece together a puzzle,” he said of contact tracers on CTV’s Your Morning Friday. “You can see how this can do so much good if it’s done well.”

But contact tracing is only effective if it goes hand-in-hand with rapid diagnostic testing, says Bogoch.

Qualifications for contact tracers vary across the country. Some jurisdictions have hired nurses to do this work, while others decided they just needed “smart, motivated, good people who can take a good history and who can follow up.”