Tuberculosis (TB) is an infectious disease primarily affecting the lungs, but can also impact other body parts like the kidneys, spine, or brain. It remains a global public health concern, causing illness and, if untreated, can be fatal. Understanding TB’s nature, spread, and management is important.
What is Tuberculosis
Tuberculosis is caused by Mycobacterium tuberculosis. Inhaled bacteria settle in the lungs and grow. Not everyone exposed develops active disease; some develop latent TB infection (LTBI). In LTBI, bacteria are inactive, causing no symptoms and not contagious.
The immune system keeps bacteria contained, preventing multiplication. If the immune system weakens, bacteria can become active, leading to active TB disease. Active TB means bacteria multiply, cause symptoms, and can spread to others.
How Tuberculosis Spreads
Tuberculosis spreads through the air when a person with active TB in their lungs or throat coughs, sneezes, speaks, sings, or laughs. These actions release tiny droplets containing bacteria into the air, which others can breathe in, leading to infection.
Germs can remain airborne for hours, especially in indoor areas with poor circulation. Close, extended contact with someone who has active, contagious TB is required for transmission. TB is not spread through casual contact like shaking hands, sharing food or drinks, touching bed linens, or kissing.
Recognizing Tuberculosis Symptoms
Active TB lung symptoms begin gradually, worsening over weeks. A persistent cough lasting over three weeks is common, sometimes with blood or mucus. Chest pain, especially when breathing or coughing, may also occur.
Beyond respiratory symptoms, active TB can manifest systemically. These include fever, chills, night sweats, unexplained weight loss, loss of appetite, fatigue, and weakness. Latent TB infection, in contrast, presents no symptoms.
Diagnosis and Treatment Approaches
Diagnosis begins with screening tests like the TB skin test (TST) or TB blood tests (Interferon-Gamma Release Assays, IGRAs). A positive result indicates bacterial exposure, but not active disease. If initial tests are positive, further evaluation is necessary.
A chest X-ray looks for lung changes suggesting active TB. If abnormalities are found, sputum smears and cultures are conducted. These tests analyze phlegm to detect Mycobacterium tuberculosis and determine antibiotic susceptibility.
Active TB treatment involves multiple antibiotics, taken for six to twelve months. Completing the entire prescribed course is important to eliminate all bacteria and prevent drug-resistant TB. For latent TB, medication may also be prescribed, often for a shorter duration, to prevent progression to active disease.
Preventing Tuberculosis
Preventing tuberculosis spread involves public health measures and individual actions. For active TB patients, isolation and medication adherence prevent further transmission. Those with active lung or throat TB may be advised to stay home and cover their mouth when coughing, especially during initial treatment weeks.
Contact tracing identifies and tests close contacts of active TB patients. For latent TB, taking prescribed medication is a primary prevention method. The Bacillus Calmette-Guérin (BCG) vaccine is available, primarily used in high-burden countries to protect infants and young children from severe TB forms, though its effectiveness against adult pulmonary TB varies.