Infectious disease epidemiology.
D002648:Child; D003141:Communicable Diseases / Q000453:epidemiology*; D004219:District of Columbia; D006801:Humans; D009175:Mycoplasma Infections / Q000453:epidemiology; D012141:Respiratory Tract Infections / Q000453:epidemiology; D013290:Streptococcal Infections / Q000453:epidemiology; D014777:Virus Diseases / Q000453:epidemiology