Epidemiology and pathogenesis of influenza.
D002648:Child; D002675:Child, Preschool; D004660:Encephalitis / Q000209:etiology; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology; D009975:Orthomyxoviridae / Q000472:pathogenicity; D011014:Pneumonia / Q000209:etiology