From the Centers for Disease Control. Influenza activity--United States, 2001-2002 Season.
D004196:Disease Outbreaks; D006801:Humans; D009980:Influenza A virus; D009981:Influenza B virus; D007251:Influenza, Human / Q000453:epidemiology*; D012621:Seasons; D014481:United States / Q000453:epidemiology