Canadian Teen in Critical Condition with First Human Bird Flu Case

A teenager in Canada is critically ill with the country's first human case of H5N1 bird flu, and health officials are uncertain about the source of exposure. The teen had no known contact with livestock, and the virus variant typically circulates in wild birds and poultry. This case raises concerns about the virus's potential to spread undetected, although officials believe it may be an isolated incident. H5N1 has a high mortality rate and has been evolving to spread more easily between mammals, though it remains less transmissible than seasonal flu.