Tuberculosis is an infectious disease caused mainly by the bacterium Mycobacterium tuberculosis, known as Koch's bacillus. Although it mostly affects the lungs, it can reach almost any organ, including the kidneys, bones, lymph nodes and meninges.
Despite being known for centuries and having effective treatments, the disease remains a significant public health problem in many countries, particularly where poverty, overcrowding, malnutrition and limited access to healthcare prevail.
It spreads through the air, via droplets released when coughing, sneezing or speaking. It is not transmitted through shared objects such as cutlery or clothing. The most characteristic symptom of the pulmonary form is a persistent cough, especially when it lasts more than three weeks.