Tom Frieden, the director of the Centers for Disease Control and Prevention, has been a central player and one of the most public figures in fighting infectious diseases in the United States. Appointed to his position in 2009 by President Obama, the 56-year-old New York native has led the Atlanta-based CDC longer than any director since the 1970s. His tenure has been tested by major disease outbreaks, including the 2009 global H1N1 swine flu pandemic and deadly respiratory virus known as MERS, the Ebola and Zika epidemics, and a growing domestic overdose crisis.