<prompt> WHO declared that smallpox has been eradicated inJun-92Dec-00May-80Jan-85  <response>: Smallpox is an acute contagious disease caused by the variola virus, a member of the ohopoxvirus family. It was one of the world;s most devastating diseases known to humanity. The last known natural case was in Somalia in 1977. It was declared eradicated in 1980 following a global immunization campaign led by the World Health Organization. 