Case of B.C. teen with avian flu shows ‘worrisome’ mutation of virus

Infectious disease experts say the avian flu case that infected a 13-year-old in British Columbia shows “worrisome” signs that the virus could be mutating to more easily infect humans, but that the treatment approach taken can help inform future cases.In a letter published in the The New England Journal of Medicine Tuesday, Canadian health officials identified changes in the viral genome sequence of specimens collected from the teenager who tested positive for avian flu and was treat