Nobel Prize-winning medical researcher D. Carleton Gajdusek, 85, who studied brain diseases and infections that lie dormant for years before attacking the body, has died. He was found Dec. 12 at a hotel in Norway, where he spent several months a year, said biographer Robert Klitzman of Columbia University.

The American scientist, who spent about two decades at the National Institutes of Health, shared the 1976 Nobel Prize in medicine for his work on "slow viruses." The infectious agents include one implicated in mad cow disease.

He spent years studying a unique group of brain diseases in the South Pacific, including one that attacked a primitive tribe in the highlands of New Guinea. He discovered it was spread through the tribe's practice of cannibalism. His research triumphs were marred by a child-molestation case when in 1997 he pleaded guilty to molesting a teenage boy. After serving one year in jail, he left the United States and spent his time abroad.

- AP