John Frame, who died January 16 at 90, was a missionary doctor who identified Lassa fever, a viral disease that infects up to half a million people in West Africa each year, killing about 5,000.

It was Frame’s insight that the hemorrhagic symptoms that killed several missionary nurses were manifestations of a previously unknown disease. So virulent was the pathogen that several researchers were infected and one died when it was first identified in 1969.

While progress has been made in both treatment and prevention of the disease, it continues to affect thousands each year in Nigeria, Uganda, and other African nations.

John Davidson Frame was born in 1917 in Rasht, Iran, where his father, also John Frame, was a protestant missionary and chief physician at the American Hospital. The family returned to America for quadrennial rotations, and Frame Jr. settled in Wooster, Ohio, in the early 1930s, in part to avoid being drafted into the Persian Army.

After graduating from medical school at Northwestern University in 1943, Frame served as an army doctor in Europe during World War II. After the war, he returned to Iran, where he became medical superintendent of the American Christian Hospital in Hamadan. He came back to America in the early 1950s and opened a private practice, settling in Forest Hills. Frame continued to work with several non-denominational medical missionary societies and frequently traveled on medical business to Africa.

After a daisy chain of missionary nurses sickened and died of a mysterious fever, Frame arranged for one surviving but critically ill nurse to be returned to America for treatment.

In collaboration with the Yale Arbovirus Research Unit, Frame identified antibodies in her blood and confirmed the new disease. In 1970, Frame and his collaborators published an article in the American Journal of Tropical Medicine and Hygiene announcing the new disease.

Since then, several research initiatives have put Lassa fever into a family of viral hemorrhagic fevers that includes Rift Valley fever, Marburg hemorrhagic fever, Ebola hemorrhagic fever, and yellow fever. While antibiotics are useful in the early stages of infection, gruesome death often occurs in cases that are caught too late.

Frame also published papers on hepatitis, and retired as clinical professor emeritus from the tropical medicine division at Columbia University’s School of Public Health.

He is survived by his wife, Veronica Foldes, and his children, David Frame, Sally Kazaks, and Deborah Frame Smith.