Fourth, fifth, and sixth.
D002675:Child, Preschool; D004890:Erythema / Q000453:epidemiology*; D005077:Exanthema Subitum / Q000453:epidemiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007970:Leukopenia / Q000453:epidemiology; D006113:United Kingdom; D014481:United States