Waterloo region has its first confirmed case of COVID-19, also known as novel coronavirus.

Public health officials revealed the case Thursday morning.

Health officials say a woman in her 50s contracted the illness during a trip to Italy.

She had "mild symptoms" on flights from Milan to Lisbon and then Lisbon to Toronto on March 3.

Passengers on Flight 827, Air Portugal and Flight 259, Air Portugal are being asked to self-monitor for symptoms for the next 14 days.

Health officials say the woman took private transportation to the Grand River Hospital directly from Toronto Pearson International Airport.

Hospital staff reportedly "took all necessary precautions," and the woman was released from hospital with mild symptoms. She is self-isolating at home.

Dr. Hsiu-Li Wang is the acting medical officer of health for Region of Waterloo Public Health and Emergency Services.

She said the woman is now recovering well, and her family is in self-isolation with her.

The woman will need to be tested on two subsequent occasions, 24 hours apart, before they'll consider her free of the virus.

She said health officials are trying to speak with other passengers who were on the woman's flights. They could not say if anyone else from the region was on the flight.

"There could be, but I am expecting there will be more in the more populous areas of Ontario, like Toronto possibly," said Wang.

Health officials say the risk to people living in Waterloo region remains low.

There are now 18 positive patients and 4 resolved cases in Ontario, according to the provincial Ministry of Health.

In the meantime, people are being advised to protect themselves from germs by washing hands often, avoiding contact with people who are sick, staying home when sick, sneezing and coughing into their sleeves and avoid touching your eyes nose and mouth.