What is one of the primary sites affected by TB disease?

The primary site affected by tuberculosis (TB) disease is the lungs. This is primarily because TB is caused by the bacterium Mycobacterium tuberculosis, which is primarily transmitted through the air via respiratory droplets when an infected person coughs or sneezes. Once inhaled, the bacteria can settle in lung tissue, where they initiate the infection.

In pulmonary tuberculosis, the lungs can become damaged and functionally impaired, leading to the classic symptoms of the disease, such as a persistent cough, chest pain, and difficulty breathing. The lungs serve as the main reservoir for the bacterial growth and reproduction, which is why diagnosing TB often involves chest X-rays or sputum tests focused on lung specimens.

While TB can also affect other organs, such as the kidneys, lymph nodes, and bones, these instances occur less frequently and are typically considered extrapulmonary TB. The majority of TB cases, especially in their initial stages, present as pulmonary manifestations, which emphasizes the lungs as the primary site of infection.