This person is receiving treatment in a children’s hospital for H5 avian flu, the provincial health department said.
The source of contagion and any possible contacts are being investigated.
Officials said the infection probably came from a bird or animal.
“This is a rare event,” British Columbia Health Officer Bonnie Henry said.
“We are conducting a thorough investigation to fully understand the source of exposure here in B.C.”
Bird flu is most commonly found in wild birds and poultry, but has more recently been detected in mammals, with an outbreak in cattle seen across the United States this year.
It can occasionally infect humans through close contact or contaminated environments.
Scientists have voiced concern about the growing number of mammals becoming infected by bird flu, even if cases in humans remain rare.
They fear a high rate of transmission could facilitate a mutation of the virus, which could enable it to be passed from one human to another.
In September officials said a person in Missouri became the first in the United States to test positive for bird flu without a known exposure to infected animals.
All previous bird flu cases in the United States have been among farmworkers, including the very first, in 2022.
In the decades since H5 has been found in humans, there have been rare cases where an animal source cannot be identified.
But there has so far not been evidence of sustained human-to-human transmission, which would significantly increase the threat level.
By AFP