Vancouver Coastal Health says two cases of measles have been confirmed in the city this month.
At a news conference Wednesday, the health authority said the first patient caught the infection abroad, but the second acquired it locally.
- Read more: What you need to know about measles
"We have gone ahead and notified anyone who may have been exposed to our most recent case of measles," Dr. Althea Hayden said.
She did not provide specifics, but said that the patient is school-aged.
Hayden also said the cases aren't linked: "We have a bit of a mystery."
She said public health officials are working hard to find out how the virus was introduced to the community, and to ensure there's no further transmission.
The news comes just weeks after the B.C. Centre for Disease Control issued a warning due to an outbreak south of the border.
Measles is highly infectious, spreads through the air, and can linger in a room for hours after an infected person has left.
In addition, it can be spread through sharing food and drinks and kissing.
Initially, symptoms are similar to a cold: fever, cough and runny nose. Those who've been infected may also have red eyes.
In the days that follow, a rash spreads from the face to the chest, but by that point, they've already been contagious for as many four days. They're contagious for four days after the rash starts as well.
While measles patients simply require rest and fluids, complications can include pneumonia, inflammation of the brain, deafness, seizures and even death.