Bird flu in Canada may have mutated to become more transmissible to humans

Scientists are racing to understand what a hospitalized teen's case of bird flu may mean for future outbreaks

The teenager hospitalized with bird flu in British Columbia, Canada, may have a variation of the virus that has a mutation making it more transmissible among people, early data shows - a warning of what the virus can do that is especially worrisome in countries such as the US where some H5N1 cases are not being detected.

The US absolutely" is not testing and monitoring bird flu cases enough, which means scientists could miss mutated cases like these, said Richard Webby, a virologist at St Jude children's research hospital's department of infectious diseases.