What is tuberculosis? Types, symptoms, causes, treatment, and prevention

Tuberculosis (TB) is a contagious infectious disease caused by Mycobacterium tuberculosis that primarily affects the lungs but can also spread to other organs like the brain, spine, and kidneys. Despite being preventable and curable, TB remains one of the leading causes of death from a single infectious agent worldwide. World TB Day, observed annually on 24 March, raises awareness about the disease and the importance of early diagnosis, consistent treatment, and preventive measures. Understanding how TB spreads, its symptoms, treatment options, and how health insurance covers TB-related expenses helps individuals protect themselves and their families.

What is tuberculosis?

Tuberculosis is caused by the bacterium Mycobacterium tuberculosis, which spreads through the air when an infected person coughs, sneezes, or talks, releasing tiny droplets that others can inhale. Not everyone who is infected becomes sick. Some people carry the bacteria in an inactive form (latent TB), while others develop active TB with visible symptoms. Active pulmonary TB is contagious and requires immediate treatment to prevent further transmission.

Types of tuberculosis

Tuberculosis (TB) can show up in different forms depending on how the bacteria behave and which part of the body they affect. Below are the main types explained in a clear and simple way.

Causes and transmission

TB is caused by inhaling airborne droplets containing Mycobacterium tuberculosis from someone with active pulmonary TB. The bacteria can remain dormant in the body for years or become active depending on the strength of the immune system.

Risk factors that increase susceptibility to active TB include the following.

• Weakened immune system from conditions like HIV/AIDS, diabetes, cancer, or immunosuppressive medications.

• Malnutrition and poor overall health compromise the body’s ability to fight infection.

• Substance abuse, including alcohol and drug use, weakens immune defences.

• Close contact with active TB patients, especially in enclosed, poorly ventilated spaces.

• Crowded living or working conditions, such as prisons, shelters, and healthcare facilities, where transmission risk is higher.

• Travel or residence in areas with high TB prevalence.

Symptoms of tuberculosis

Symptoms depend on whether TB is latent or active and which organs are involved. Latent TB has no visible symptoms. Active pulmonary TB presents the following common signs.

• Persistent cough lasting more than 3 weeks, often producing sputum.

• Coughing up blood or sputum (haemoptysis).

• Chest pain or discomfort while breathing or coughing.

• Fatigue and weakness that do not improve with rest.

• Unintentional weight loss and loss of appetite.

• Fever that is often low-grade and persistent.

• Night sweats that soak bedding and clothing.

If you experience any of these symptoms for more than 3 weeks, consult a doctor immediately for TB testing.

Diagnosis of tuberculosis

TB is diagnosed through a combination of tests, depending on whether latent or active TB is suspected.

• Mantoux tuberculin skin test (TST). A small amount of tuberculin is injected under the skin of the forearm. A raised bump that appears after 48 to 72 hours may indicate TB infection.

• Interferon-gamma release assays (IGRAs). Blood tests that detect an immune response to TB bacteria. More specific than the skin test.

• Chest X-ray. Detects abnormalities in the lungs that suggest active pulmonary TB.

• Sputum test. Sputum samples are analysed under a microscope and cultured to confirm the presence of Mycobacterium tuberculosis.

• GeneXpert/CBNAAT. A rapid molecular test that detects TB bacteria and drug resistance within 2 hours, widely used in India.

Treatment of tuberculosis

TB is treatable and curable with a proper course of antibiotics. The standard treatment involves a combination of four first-line drugs (isoniazid, rifampicin, pyrazinamide, and ethambutol) taken for 6 to 9 months. The first 2 months (intensive phase) use all four drugs, followed by 4 to 7 months (continuation phase) with two drugs.

Consistency is critical. Stopping treatment early or missing doses can lead to drug-resistant TB (MDR-TB or XDR-TB), which is harder and more expensive to treat. India’s national TB programme (NTEP) provides free diagnosis and treatment through government health facilities under the DOTS (Directly Observed Treatment, Short-course) strategy.

Prevention of tuberculosis

Preventing tuberculosis is possible with a mix of vaccination, early care, and simple everyday precautions that stop the spread of infection.

• BCG vaccination: Given to newborns in India as part of the national immunisation programme. It provides partial protection against severe forms of TB in children.

• Early detection and treatment: Identifying and treating active TB cases promptly reduces transmission in the community.

• Infection control: Good ventilation, respiratory hygiene (covering the mouth while coughing), and wearing masks in high-risk settings help prevent airborne transmission.

• Screening high-risk groups. Regular TB screening for people living with HIV, healthcare workers, and close contacts of TB patients helps detect cases early.

• Completing full treatment. Ensuring every diagnosed patient completes the full course of medication prevents the development of drug-resistant strains.

How does tuberculosis spread?

TB spreads only through airborne droplets from a person with active pulmonary TB. It does not spread through handshakes, sharing food or utensils, touching surfaces, or insect bites. Prolonged close contact with an infected person in an enclosed space with poor ventilation increases the risk of transmission. A single cough from an active TB patient can release thousands of infectious droplets that remain suspended in the air for several hours.

Tuberculosis and health insurance

Most comprehensive health insurance plans in India cover the diagnosis and treatment of tuberculosis, including hospitalisation, diagnostic tests, prescribed medications, and follow-up consultations. TB treatment under the government’s NTEP programme is provided free of charge, but private treatment and hospitalisation for complications may involve high costs that health insurance can cover.

• Hospitalisation expenses for TB-related admissions, including ICU stays if needed.

• Diagnostic tests include chest X-rays, sputum culture, GeneXpert, and blood tests.

• Pre and post hospitalisation expenses for medications and follow-up visits.

• Coverage for complications such as drug-resistant TB requiring extended treatment.

Pre-existing TB may be subject to a waiting period before coverage begins, depending on the insurer’s terms. Zurich Kotak General Insurance offers health plans that cover TB-related medical expenses as part of their comprehensive coverage.

Conclusion

Tuberculosis remains a significant health challenge, but it is preventable, diagnosable, and curable with proper treatment. Early detection through symptom awareness and timely testing, combined with a full 6 to 9 month course of antibiotics, achieves high cure rates. The BCG vaccine provides partial protection in children, and good respiratory hygiene reduces transmission risk. Health insurance covers TB-related diagnosis, treatment, and hospitalisation costs, providing financial protection during what can be a lengthy treatment process.

Read more - Health Insurance: Complete Overview of What, Why, How & Coverage

FAQs

Q1: What causes tuberculosis?

TB is caused by Mycobacterium tuberculosis, a bacterium that spreads through airborne droplets when an infected person coughs or sneezes.

Q2: What are the main symptoms of TB?

Persistent cough for over 3 weeks, coughing up blood, chest pain, fever, night sweats, weight loss, and fatigue are common symptoms.

Q3: Is tuberculosis curable?

Yes, TB is curable with a full 6 to 9 month course of antibiotics. Completing the entire treatment is essential to prevent drug resistance.

Q4: Does health insurance cover TB treatment?

Yes, most comprehensive plans cover TB hospitalisation, diagnostics, and medications. Pre-existing TB may be subject to a waiting period.

Q5: How can TB be prevented?

BCG vaccination, early detection, respiratory hygiene, good ventilation, and completing prescribed treatment help prevent TB transmission.

Q6: Is TB contagious?

Active pulmonary TB is contagious and spreads through airborne droplets. Latent TB and extrapulmonary TB are generally not contagious.