Influenza.
D000328:Adult; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D007223:Infant; D007231:Infant, Newborn; D009980:Influenza A virus / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology* / Q000382:microbiology; D007558:Italy / Q000453:epidemiology; D008875:Middle Aged; D008923:Missouri / Q000453:epidemiology; D011174:Portugal / Q000453:epidemiology; D014416:Tunisia / Q000453:epidemiology; D014481:United States / Q000453:epidemiology