COVID-19 transmission 'largely under control' but relapses possible: Dr. Tam

Canada's chief public health officer said todaytransmission of the novel coronavirus is largely under control in this country, but warned that the caseload can flare up at any time.

"The epidemiologyindicates thattransmission is largely under control, while also showing us that cases can reemerge at any time or place," Dr. Theresa Tam told an updated modelling briefing Monday.

"Dynamic models are telling us that if we relax too much or too soon the epidemic will most likely rebound with explosive growth as a distinct possibility."

The number of daily cases is steadily declining, along with the numberof hospitalized and critical care cases, said Tam.

She warned, however,that lifting pandemic measures too soon without a proper system of contact tracing and isolation likely would lead torelapses.

"The novel coronavirus has not been eliminated and we do not have an effective vaccine at this time. So as restrictive public health measures are being lifted to minimize the unintended health, social and economicconsequences we expect to see some resurgence of cases," she said.

"The key is to keep the number of cases small."

After months of strict travel rules and widespread business shutdowns, more provinces are easing restrictions.Later this week, the four Atlantic provinces will open their borders to each other, meaning residents in those areas can travel without having to self-isolate for 14 days.

Outbreaks in Windsor-Essex, Kingston

But efforts to reopen haveexperiencedsetbacks in multiple provinces.

The updatedPublic Health Agency of Canada figures show that some areas have been more heavily affectedby COVID-19 than others specifically Quebec and Ontario and identifiedsome recent regional hotspots, including parts of Saskatchewan, the cities of Toronto andMontreal and around the border town of Windsor, Ont.

Of Ontario's 257 confirmed new cases of COVID-19, reported today, 177 are from the Windsor-Essex area. The provincial caseload grew sharplyfollowingtargeted testing of migrant farm workers over the weekend.

Tam touched on the issue of migrant farm workersduring her briefing with colleague Dr. Howard Njoo today. Shesaid the pandemic has exposed vulnerabilities in crowded settingssuch as long-term care homes, meat plantsandthe congregate housing facilities wheremany agricultural workers live while in Canada.

Hundreds of people in the Kingston, Ont., area are also being tested for possibleexposure to the novelcoronavirusafter an outbreak at a local nail salon. The local health unit confirmed on Monday that 25 people have tested positive for COVID-19 after working at, visiting or coming into contact with someone who was at the salon.

And British Columbia, which has moved into Phase 3 of its reopening plan,isseeing a sustained rise in cases for the first time in months, with hospitalizations at theirhighest point since June 7 and the five-day rolling average of new cases the highest since May 17.

Canada watching situation in the U.S.: PM

Whileinterprovincial borders continue to open up,Prime Minister Justin Trudeau said his government continues to monitor the COVID-19count in the United States, which has reported more than 2.5 million cases and more than 125,000 deaths.

"We will continue to assess the situation and work with the Americans on what steps need to be taken into the month of August," said Trudeau, referring to the travel restrictions at the U.S. border which areset to expire next month.

"What the situation we're seeing in the United States and elsewhere highlights for us is that, even as our economy is re-opening, we need to make sure we are continuing to remain vigilant, individually and collectively."

More than 500,000 people have died worldwide of the illness caused by the virus, according to a tally fromJohns Hopkins University researchers.

Canada has had more than103,000 cases and more than 8,500 deaths.