Tiny genetic alterations could help the bird flu virus enter cells in the upper respiratory tract, the C.D.C. said. But there is no sign that mutations are widespread in nature. Avian Influenza, Vaccination and Immunization, Livestock, Birds, Influenza, British Columbia (Canada), Louisiana NYT > Health
Tiny genetic alterations could help the bird flu virus enter cells in the upper respiratory tract, the C.D.C. said. But there is no sign that mutations are widespread in nature.
