Which disease is caused by Mycobacterium tuberculosis and typically involves the lungs?

• A. URI
• B. Influenza
• C. Tuberculosis (TB)
• D. SIDS

Answer: (C)

Tuberculosis is a lung-focused infection caused by Mycobacterium tuberculosis. It spreads through airborne droplets when someone with the bacteria coughs or sneezes, making the lungs the most common site of disease. Typical signs include a prolonged cough, possible coughing up blood, fever, night sweats, and unintended weight loss. Diagnosis uses a combination of tests: exposure screening (tuberculin skin test or IGRA), chest imaging to look for lung involvement, and microbiologic confirmation with sputum smears or cultures showing acid-fast bacilli. Treatment requires a longer course of multiple antibiotics to prevent resistance. The other choices describe conditions not caused by this bacterium or not primarily involving the lungs.