is a contagious disease caused by a bacterium from the mycobacteria family, usually the mycobacterium tuberculosis. Once the bacteria has come into contact with the body, often unremarked or provoking minor symptoms, the disease infests an organ and stays dormant. The most commonly affected organ is the lung, but the lymph nodes can also be affected by quiescent bacilla. Tuberculosis therefore manifests with the appearance of swollen lymph nodes, or lymphadenopathy. Diagnosis can be established by biopsy
of an affected lymph node, meaning by extracting a sample that is analyzed for tuberculosis bacteria.