Swine influenza.
D000818:Animals; D003430:Cross-Sectional Studies; D004739:England / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D009980:Influenza A virus / Q000145:classification / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology* / Q000382:microbiology; D014481:United States / Q000453:epidemiology