Tuberculosis patient providing a sputum sample to assess whether his drug treatment has been successful. The sputum, material coughed up from the lungs, will be tested for the presence of the Mycobacterium tuberculosis bacterium that causes pulmonary tuberculosis (TB). The bacteria grow into a primary tubercle (nodular lesion) when inhaled into the lungs. In some people, the disease then spreads to the lymph nodes. Tuberculosis is transmitted by coughing or sneezing. Symptoms include fever and weight loss, and the disease can be fatal. Photographed at Navrongo Hospital, Ghana, in 1999.