A second, presumptive case of the coronavirus has been identified in B.C., according to provincial health officer Dr. Bonnie Henry.

A Vancouver-area woman in her 50s is believed to have the virus after a preliminary test came back positive Monday night. The result needs to be confirmed by the National Microbiology Lab in Winnipeg.

"I fully expect [it] will come back as positive," Henry said at a news conference Tuesday.

Henry says the woman became ill a few days ago and is in contact with the health authority.

"Vancouver Coastal [Health] is working diligently to get all of the details … around this person," said Henry.

The woman had been in contact with family visitors from Wuhan, China — the epicentre of the outbreak — who are still in her home, in isolation. Henry says health officials are monitoring them.

"If you are somebody who has been in Hubei province [in China] within the last two weeks, it's really important that you take measures to keep away from others and consider staying at home," she said.

The coronavirus has infected more than 20,400 people worldwide, and killed 425 according to the World Health Organization. The UN agency has also confirmed 27 cases of the virus spreading person-to-person in countries outside of China.

WATCH | Dr. Bonnie Henry announces second presumptive case of coronavirus in B.C.

B.C.'s provincial health officer Dr. Bonnie Henry says a woman in her 50s was in contact with family who travelled from Wuhan, China, but those relatives minimized contact with others. 1:58

Before being allowed out of isolation, Henry says a patient must test negative for the virus twice, 24 hours apart.

She said the province's quick detection of this case is proof that its protection and prevention system is working.

Ottawa is preparing to evacuate Canadians from Hubei, and could fly them back as early as Thursday, after which they will be quarantined at an airbase in Trenton, Ont.

Henry said the plane will refuel at Vancouver International Airport and that B.C. is preparing to assist if any evacuees require immediate medical attention.

Anyone with concerns about coronavirus infection should contact their local health authority, Henry said.

B.C.'s first case of coronavirus was confirmed on Jan. 29, also in the Vancouver region.

The patient — a man in his 40s — developed symptoms after flying back from a business trip to Wuhan. Other passengers who were on the flight were not believed to be at risk, according to Henry.

The patient had limited contact with others since arriving back in B.C., she said, and was in isolation at home.