When Susan Blank was completing her training to become a pediatrician, she spent a few months in Tanzania during her residency–and her interests changed abruptly. “I saw a lot of preventable morbidity,” she says. “I was really struck by that.”

Her Tanzania trip came at the last stage of her medical training at Yale-New Haven Hospital, after she had finished her MIT biology degree and, in 1987, medical school at the University of Pittsburgh. In 1990, she followed her new interest and joined the U.S. Centers for Disease Control’s Epidemic Intelligence Service. On assignment in New York City, Blank now serves as assistant commissioner in the Bureau of STD Control and Prevention at the New York City Department of Health and Mental Hygiene. In line with this work, she earned a master’s degree in public health at Columbia University in 1997.

Blank has become one of sexually transmitted diseases’ most formidable foes. For example, in 2002, when the city’s syphilis rate first showed steep increases, Blank’s bureau tracked down the cases and interviewed the patients. They found that the rise was attributable to men having sex with men and that 60 percent of people with syphilis were also infected with HIV. That’s the kind of detective work that brings Blank tremendous satisfaction, because it calls on myriad talents–medical knowledge, analytical thinking, and social skills. It helps curb the spread of disease, fosters healthy and rational decision making among those at risk, and leads to policies and programs promoting behavior that prevents the spread of STDs. For example, the bureau, which offers free and confidential care, routinely reaches out to sex partners of infected men–by phone, in person, via e-mail, or through online chat rooms–to advise them to be tested for syphilis and HIV.

“Although the data are key in targeting our interventions, sexual behavior is a critical factor in sexual health,” Blank says. “The public-health endeavor is there to help a lot of people. To do it wisely, you have to be quantitative, and MIT is a very good place for learning that kind of discipline.” Instead of treating individual patients, she says, her job is to treat whole strata of society.

“There’s a lot of appeal in that,” adds Blank, who lives in Forest Hills, Queens, with her husband, Barry Gloger ‘69, an orthopedic surgeon, and their eight-year-old son.