Which disease is an infectious disease caused by Mycobacterium tuberculosis; lungs usually are involved, but any organ in the body may be affected?

• A. URI
• B. TB
• C. SIDS
• D. Influenza

Answer: (B)

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis. The lungs are usually involved, which is why it’s most commonly referred to as pulmonary TB, but the bacteria can spread through the body and affect virtually any organ. Transmission occurs via airborne droplets when someone with active TB talks, coughs, or sneezes. Many people harbor the bacteria in a latent form without symptoms and without being contagious; active TB causes a persistent cough, fever, night sweats, weight loss, and sometimes coughing up blood. Diagnosis involves tests such as the tuberculin skin test or IGRA, along with chest imaging and sputum analysis. The other options don’t fit because they are not caused by Mycobacterium tuberculosis: those conditions are caused by different pathogens or are not infectious diseases.