title: Human infection with new influenza A (H1N1) virus: clinical observations from Mexico and other affected countries, May 2009.
mesh_terms: D000328:Adult; D002170:Canada / Q000453:epidemiology; D006760:Hospitalization; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000453:epidemiology* / Q000628:therapy / Q000821:virology; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D014481:United States / Q000453:epidemiology