William Trager, 94; Scientist Specialized in Research Into Malaria

William Trager, 94, an expert on parasitic diseases who was the first to culture the most lethal form of malaria parasite, died Saturday at his New York City home. He was believed to have suffered a heart attack.

Trager taught for 60 years at Rockefeller University, which in 1976 announced that he had found a way to use human blood as the growth medium for Plasmodium falciparum, the deadliest of four varieties of malaria.

His discovery raised hopes that that a vaccine against malaria could be developed. Malaria was then killing about 1 million children a year. Although the search for a vaccine continues to this day, Trager’s laboratory breakthroughs influenced modern-day researchers.

Educated at Rutgers University and Harvard, where he earned a doctorate in 1933, Trager was a captain in the U.S. Army’s Sanitary Corps during World War II, when he was stationed in Australia to oversee trials of a new drug, Atabrine, which was believed to help troops resist malaria.

After the war, he successfully experimented with culturing a form of malaria found in birds, before moving on to work with human strains of the disease. He found improved methods for growing mosquito larvae, as well as the tissues of tsetse flies and silkworms, which carry such diseases as sleeping sickness and encephalitis.