Tuberculosis. Man with breathing difficulties due to pulmonary tuberculosis (TB) being supplied with oxygen through a nasal tube. 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. Tuberculosis is transmitted by coughing or sneezing. Symptoms include fever, weight loss and the coughing up of blood. The disease can be fatal. Photographed in a TB hospital ward in Changsha, Hunan Province, China, in 1999.