Three North Carolina surveys.
D001766:Blindness / Q000453:epidemiology*; D006801:Humans; D009136:Muscular Dystrophies / Q000453:epidemiology*; D009657:North Carolina; D011051:Poliomyelitis / Q000453:epidemiology*
BLINDNESS/epidemiology; POLIOMYELITIS/epidemiology; PROGRESSIVE MUSCULAR DYSTROPHY/epidemiology