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As new outbreaks of coronavirus continue to appear in countries outside China, experts are now recalculating the risk of the virus and our ability to contain it worldwide.

Until now, the focus of containing the coronavirus illness, known as COVID-19, has centred on China.

Millions remain under quarantine in China's central Hubei province, where the outbreak began, and travel restrictions are still in place throughout the affected region.

But outbreaks have since emerged in South Korea, Italy and Iran. Infectious disease physicians say the rapid spread of coronavirus cases outside China could signal a game changer in the response to the global outbreak.

"Globally, we will not be able to contain the spread of this virus. We can slow it down, but we can't stop it," said Dr. Allison McGeer, an infectious diseases specialist at Toronto's Mount Sinai Hospital who worked on the front lines of the SARS epidemic in 2003.

"The number of countries with cases is going to continue to increase."

The WHO is increasingly concerned about COVID-19 outside China, especially in South Korea and Iran. 2:51

Officials are also concerned about the number of cases with "no clear epidemiological link," WHO Director-General Tedros Adhanom Ghebreyesus said Friday, such as travel history to China or contact with a known confirmed case.

He said while the number of cases outside China remains small, they are "worrisome."

"It's in our hands now," Tedros said. "If we do well within the narrowing window of opportunity, we can avert any serious crisis. If we squander the opportunity, then there will be a serious problem on our hands."

1st case in Canada with no connection to China

Canada's ninth presumptive case of coronavirus is a woman in her 30s who recently travelled to Iran and is now recovering at home in British Columbia.

Health officials were surprised to learn she had not travelled to China or any of its neighbouring countries, and have classified the case as a "sentinel event" — one that originated from a region that is completely unexpected.

Dr. Bonnie Henry, B.C.'s provincial health officer, said they are investigating where the woman may have contracted the virus, working alongside the Public Health Agency of Canada. The woman had a travelling companion, was visiting family and is now in isolation at home.

"Until very recently, we didn't consider Iran as a place of transmission of COVID-19," Henry said in an interview. "So that set off quite a number of warning bells for us."

Henry said the investigation continues into where the woman travelled, but she hadn't been to the city of Qom, where a handful of cases have been recorded. "She did report at the airport [in Tehran] that there were quite a lot of people who were sick and who were wearing masks," she said.

The answers are important to public health measures aimed at containing the virus, such as whether Canada should expand its border-screening questionnaires for travellers from places beyond the epicentre in China's Hubei province.

An Iranian man wearing a protective mask walks at Grand Bazaar in Tehran on Thursday. (Nazanin Tabatabaee/West Asia News Agency/Reuters)

Henry said the exportation of a case from a country like Iran, which hasn't previously reported a lot of infections, also has parallels with the start of the epidemic in China.

"The first exported cases from China were similar," she said, "and essentially an indication that there may be more cases than were recognized."

If it is confirmed the traveller was infected in Iran, then it likely means there's more than a handful of cases there, said Dr. Isaac Bogoch, an infectious disease physician at Toronto General Hospital who is researching the outbreak.

"The real question is how much disease burden is in Iran and do they have the capacity to really get this under control," he said. "We might be inching toward this situation where this infection is not contained and we have to really be prepared for a possible scenario where there's more widespread transmission throughout the world."

'Alarming numbers' in South Korea

South Korea is also seeing a surge in new cases — reportedly linked to what authorities call a "super-spreading event" at a church congregation where the majority of infections originated.

"What we're hearing out of South Korea is starting to sound like alarming numbers," said Bogoch. "But South Korea has a pretty robust medical system and a fantastic public health infrastructure."

Bogoch said South Korea's health-care system was tested significantly with an epidemic of MERS in 2015, much like Toronto was with SARS in 2003.

"We learned incredible lessons from SARS that are really implemented to this day that are helping us cope with this COVID-19 epidemic," he said.

"Hopefully Korea has really learned some lessons from their MERS epidemic a few years ago to really help them cope with this."

People wearing masks wait for a signal at a crosswalk in central Daegu, South Korea on Friday. (Kim Hong-Ji/Reuters)

While managing ill patients and preventing hospital outbreaks are key to a country's health-care infrastructure, McGeer said that infrastructure may have little to do with preventing the spread of the coronavirus.

"This is not about how strong your health-care system is," she said. "They may well be able to identify chains of transmission and quarantine and isolate people. But the larger the number of cases, the more difficult it becomes."

In northern Italy, officials shut down schools and public events after a cluster of 16 cases and one death were announced Friday. Five of those cases were identified as health workers.

WHO officials have pushed for countries to be transparent about their cases, so resources can be shifted to where the need is greatest.

For WHO, sub-Saharan Africa was a concern, given the degree of travel between China and Africa and limited ability to test for the virus in many African countries.

Stephen Hoption Cann, an epidemiologist at the school of population and public health at the University of British Columbia, said if COVID-19 continues to spread worldwide, there is the possibility of the virus becoming endemic — or something that re-emerges on a seasonal basis.

"Are we going to be able to contain this virus and prevent it from spreading into the next season?" he said. "It's really hard to say now; it's looking like there's a possibility that we will be seeing it back again next winter."

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