How common is legionnaires' disease?
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005060:Europe; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007877:Legionnaires' Disease / Q000175:diagnosis / Q000453:epidemiology*; D009656:North America; D012621:Seasons