Donald Blair, MD, a professor of medicine specializing in infectious disease, is celebrating 50 years at Upstate. At the start of his career, he saw patients in Ethiopia with some of the world’s last cases of smallpox. Later, he learned in real time about the human immunodeficiency virus that causes AIDS. Currently, he has concerns about how deadly bird flu could be if it spreads to more humans. Blair also reflects on how his medical specialty has changed over five decades.