An outbreak of tuberculosis in a nursing home in Niigata Prefecture of Japan that killed 12 people between April 1995 and May 1997 has only now come to light after prefectural officials failed to alert the Ministry of Health and Welfare at the first sign of trouble. The officials finally admitted the outbreak only after being questioned as part of an Asahi Shimbun investigation. It is the first reported case of mass infection of tubercle bacillus in a nursing home in the nation, ministry officials said.