The husband of a woman confirmed as Ontario's fifth case of COVID-19 has also tested positive for coronavirus, said the province's Ministry of Health on Thursday.

The man in his 60s is at home in Toronto in self-isolation. Health officials say his only symptoms are a mild cough and fever.

Local public health officials in the city "continue to be in regular contact" with the man, a ministry statement reads.

"It is not surprising to hear this news," said Dr. Eileen de Villa, medical officer of health for the City of Toronto, during a news conference Thursday afternoon.

"We know we have a mobile population with a lot of international travel," de Villa said.

"At this time, the virus is not circulating locally. However, given the global circumstances, we are actively working with our city and health partners to plan for the potential of local spread."

Wednesday, officials said the man's wife tested positive for coronavirus, nine days after she returned from a trip to Iran.

Health Minister Christine Elliott's director of communications said the woman's husband was not in Iran with her, and so this marks the first time Ontario has seen a case of human-to-human transmission. The patients in all of the other cases had a recent travel history to China.

While China has been the epicentre of the outbreak of the virus known as COVID-19, Iran is now experiencing one of the worst outbreaks outside of China, with 254 people infected and 26 dead.

More than 81,000 cases of COVID-19 have occurred since the virus emerged in the Hubei province of China.

Ontario health officials say the risk of contracting coronavirus in Canada remains low and residents should take the same precautions as during flu season.

"We had far more cases of influenza last week than we did coronavirus," said Dr. David Williams, Ontario's chief medical officer of health.