Influenza.
D004196:Disease Outbreaks; D006801:Humans; D007251:Influenza, Human / Q000150:complications / Q000453:epidemiology / Q000517:prevention & control / Q000628:therapy; D009975:Orthomyxoviridae / Q000145:classification / Q000276:immunology; D011014:Pneumonia / Q000209:etiology