The H5N1 virus that infected a Canadian teen appears not to have spread, but it shows signs of mutation that makes flu virologists nervous.

The avian flu virus isolated from a hospitalized teenager in Vancouver has mutations in key areas that could help the virus spread more easily in humans, scientists say.

A teenager in British Columbia who is being treated in the critical care unit was confirmed to have been infected with the bird flu virus.

A Canadian teenager hospitalised with suspected H5N1 bird flu is now in critical condition, health authorities said on Tuesday. The patient, Canada’s first presumed human case of H5N1, was previously healthy and had no underlying conditions,

British Columbia health officials have yet to identify a likely source of the infection, though none of the teen's contacts have tested positive for the virus so far.

A teenager in British Columbia, Canada has been hospitalized with a presumed case of H5N1 bird flu, the first detected human case in the country in the current outbreak.

United States health officials are tracking an outbreak in bird flu cases across the country. They are seeing cases in over 400 cattle herds across 15 states.

Remember the H1N1 swine flu pandemic of 2009? Well, H5N1 bird flu could be next - H5N1 bird flu has infected more than 50 people across seven states, with cases steadily climbing

Ducks and geese on a backyard farm in Oahu, the state's main island, tested positive for H5N1 last week, which was likely brought to the island by migratory birds.