A person returning to Canada from western Africa has been hospitalised after displaying symptoms consistent with those of the Ebola virus that has killed 59 people in Guinea.
A health official said the person is critically ill.
"All we know at this point is that we have a person who is critically ill who traveled from a country where these diseases occur," Denise Werker, joint director of health in Saskatchewan province in western Canada, told reporters.
She said the casualty had been in Liberia and had developed the symptoms after landing in Canada.
He or she would not have been contagious when travelling and was now in isolation, pending test results.
Aid workers and health officials in Guinea are battling to contain west Africa's first outbreak of the deadly Ebola virus as neighbouring Liberia reported its first suspected victims.
The Liberian cases, if confirmed, would mark the first spread of the highly contagious pathogen into another country.
Ms Werker said the risk of transmission was low as the disease, one of the world's most virulent, is transmitted to humans from wild animals and between humans by direct contact with blood, feces or sweat, or by sexual contact and the unprotected handling of contaminated corpses.