Tuberculosis is an infectious disease that usually affects the lungs. Compared with other diseases caused by a single infectious agent, tuberculosis is the second biggest killer, globally. How Is It Spread? Through the air, just like a cold or the flu . When someone who’s sick coughs, sneezes, talks, laughs, or sings, tiny droplets that contain the germs are released. If you breathe in these nasty germs, you get infected. TB is contagious, but it’s not easy to catch. The germs grow slowly. You usually have to spend a lot of time around a person who has it. That’s why it’s often spread among co-workers, friends, and family members. Tuberculosis germs don’t thrive on surfaces. You can’t get the disease from shaking hands with someone who has it, or by sharing their food or drink. Who is at risk for tuberculosis? According to WHO, more than 95 percent of all deaths related to TB cases occur in low- and middle-income countries. People who use tobacco or misuse drugs or alcoh...