Tuberculosis (TB) is caused by bacteria (Mycobacterium tuberculosis) that most often affect the lungs. Tuberculosis is curable and preventable.

TB is spread from person to person through the air. When people with lung TB cough, sneeze or spit, they propel the TB germs into the air. A person needs to inhale only a few of these germs to become infected.

About one-third of the world's population has latent TB, which means people have been infected by TB bacteria but are not (yet) ill with the disease and cannot transmit the disease.

Human African trypanosomiasis, or sleeping sickness, is a widespread tropical disease that can be fatal if not treated. It is spread by the bite of an infected tsetse fly and is characterized by bouts of fever, swollen lymph glands, aching muscles and joints, headaches and itching.

In advanced stages, sleeping sickness attacks the central nervous system causing confusion, irritability, sensory disturbances, difficulty walking and talking, and disturbances of the sleep cycle, which gives the disease its name.