A CHOLERA OUTBREAK in northern Cambodia has killed 77 people and infected more than 400 others, official Phnom Penh radio reported Sunday. . . . TWO TOUR BUSES collided and exploded on the main western highway of China's southern Hainan Island, killing 14 and injuring 35, according to a report received Monday. . . . A MAN IS SUSPECTED of using a hammer to beat to death his wife, three young children and mother-in-law before stabbing and seriously wounding himself in York, Pa.