Our houses, workplaces, and even the air we breathe are teeming with microbes, some of which can cause severe illness. Dr. Catharine Bosio is an immunologist studying how airborne pathogens infect and alter cells in the lungs. Her work focuses in particular on a bacterium called Francisella tularensis, which causes a life-threatening disease called tularemia and has the unique ability to change how energy-producing mitochondria function in immune cells. Dr. Bosio's experiments with these deadly bacteria could lead to more effective ways to diagnose and treat tularemia and other infectious diseases.