Breathe in. Breathe out. In that brief moment, you can contract tuberculosis. Many science writers who fly are well aware of that possibility and the other germs that can be inhaled from fellow passengers during the trip. Reichman and Tanne point out that tuberculosis is an airborne disease that will infect 8.4 million people this year, and kill 2 million. TB, they say, has never gone away and now it is bigger threat than ever before in history.