title: Investigations reveal rare mutation event in avian influenza outbreak.
mesh_terms: D000818:Animals; D000835:Animals, Wild; D001717:Birds; D004196:Disease Outbreaks; D053126:Influenza A Virus, H7N7 Subtype / Q000235:genetics* / Q000472:pathogenicity; D005585:Influenza in Birds / Q000453:epidemiology / Q000821:virology*; D009154:Mutation; D011200:Poultry; D011201:Poultry Diseases / Q000453:epidemiology / Q000821:virology*; D006113:United Kingdom / Q000453:epidemiology