A bacterial infection that affects the lungs and is caused by Mycobacterium tuberculosis. Most patients with tuberculosis do not have symptoms (latent tuberculosis) and are not contagious. When signs and symptoms occur (active tuberculosis), patients become contagious. The signs and symptoms include chronic cough with blood-tinged sputum, night sweats, fever, fatigue, and weight loss. The disease is pulmonary tuberculosis (MONDO_0006052, a Monarch Disease Ontology identifier). Also known as: lung TB, lung tuberculosis, pulmonary TB.