Tuberculosis. Doctor using a stethoscope to listen to the lungs of a woman with pulmonary tuberculosis (TB). Tuberculosis is caused by the Mycobacterium tuberculosis bacterium, which grows into a primary tubercle (nodular lesion) when inhaled into the lungs. In some people, the disease then spreads to the lymph nodes. TB is transmitted by coughing or sneezing. Symptoms include fever and weight loss, and the disease can be fatal. The patient was taking DOTS (directly- observed treatment, short-course) drugs, but stopped while still infected. She has now presented herself for treatment again. Photographed in Buenos Aires, Argentina, in 1999.