Tuberculosis

Tuberculosis (TB) is a bacterial infection caused by Mycobacterium tuberculosis. It usually affects the lungs (pulmonary TB) but can affect any organ — spine (Pott's disease), abdomen, brain, lymph nodes, joints, or almost any tissue. India has the world's largest TB burden — accounting for roughly a quarter of global TB cases. TB is curable with proper treatment, and testing and medicines are free.

How TB spreads

Through the air — when a person with active pulmonary TB coughs, sneezes, or speaks, tiny infected droplets can be inhaled by others. TB does NOT spread through shaking hands, sharing food or drinks, or touching surfaces. Prolonged close contact matters; brief contact rarely transmits.

Latent vs active TB

• Latent TB — the bacterium is in the body but not causing illness. No symptoms, not contagious. Can reactivate later, especially if immunity weakens (e.g. HIV, diabetes, steroids).
• Active TB — the bacterium is multiplying and causing illness. Symptoms are present; pulmonary TB is contagious.

Symptoms of active TB

Symptoms are often gradual — over weeks to months:

• Persistent cough (more than 2-3 weeks), sometimes with blood-streaked phlegm
• Fever, usually low-grade in the evenings
• Night sweats
• Unintended weight loss
• Loss of appetite
• Tiredness, weakness
• Chest pain
• For extra-pulmonary TB: symptoms depend on the organ affected (back pain for spinal TB, abdominal pain and ascites for abdominal TB, headache and neurological signs for TB meningitis, etc.)

Any cough lasting 2-3 weeks or longer in India should be tested for TB — testing is free.

Who is at higher risk?

• Close contacts of people with TB
• People living in crowded or poorly-ventilated conditions
• Malnutrition
• HIV
• Uncontrolled diabetes
• Smokers
• People on immunosuppressive medicines
• Elderly and very young

Diagnosis

Diagnosis depends on the site:

• Sputum tests for pulmonary TB — Xpert MTB/RIF (fast molecular test, also detects rifampicin resistance), sputum smear microscopy
• Chest X-ray
• CT scan — for complicated cases
• Biopsy and fluid tests — for extra-pulmonary TB
• Tuberculin skin test (Mantoux) and IGRA blood test — for latent TB
• All diagnostic testing is free at government health facilities

Treatment

TB is treated with a combination of antibiotics taken over a prolonged period:

• Drug-sensitive TB — usually 6 months of multi-drug therapy
• Drug-resistant TB (MDR-TB, XDR-TB) — longer courses of different medicines; care is more intensive. India has dedicated MDR-TB treatment centres.
• All TB medicines are provided free
• DOT (directly observed treatment) and treatment support — to help completion; non-completion is a major reason for resistance

Completing the full course is essential — stopping early, even when symptoms improve, can cause relapse and drug resistance. Treatment transforms TB from fatal to curable in most cases.

Prevention

• BCG vaccine in infancy — provides protection against severe childhood TB (meningitis, disseminated TB); less effective against adult pulmonary TB. Given at birth in India's routine immunisation.
• Early diagnosis and treatment of active cases — the most effective way to stop transmission
• Good ventilation at home and in workplaces
• Cover coughs and sneezes; wear a mask if coughing
• Screening and preventive treatment for close contacts — particularly children and immunocompromised people
• Nutrition, managing diabetes, HIV control — all reduce risk