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Category: Respiratory | Medical Specialist: Pulmonologist; primary-care physician; allergist where appropriate | References: Global Initiative for Asthma (GINA); Global Initiative for Chronic Obstructive Lung Disease (GOLD); WHO; CDC Introduction: Why Tuberculosis Still Matters A cough that refuses to go away can seem ordinary—until it isn’t. Tuberculosis (TB) remains one of the world’s most important infectious diseases, despite being preventable and curable. According to the World Health Organization (WHO), an estimated 10.7 million people developed TB in 2024, while about 1.23 million people died from the disease. India alone accounted for roughly 25% of global TB cases in 2024. What makes Tuberculosis particularly challenging is that it can be surprisingly quiet. Some people have symptoms for months before seeking care, while others have TB bacteria in their bodies without feeling ill at all. The encouraging part is equally important: TB can be diagnosed, treated and cured. The key is recognizing warning signs early, getting the right tests, and completing treatment exactly as prescribed. What Is Tuberculosis? Tuberculosis is an infectious disease caused by the bacterium Mycobacterium tuberculosis. It most commonly affects the lungs, where it is called pulmonary TB, but the bacteria can also affect other organs. TB spreads primarily through the air. A person with infectious pulmonary or laryngeal TB can release bacteria when coughing, sneezing, speaking or singing. Close, prolonged exposure—particularly in poorly ventilated spaces—can increase the chance of transmission. However, TB infection and TB disease are not the same thing. After someone inhales TB bacteria, the immune system may contain them. The bacteria can remain inactive, producing what is commonly called TB infection or latent TB. These people generally do not feel sick and do not spread TB. WHO estimates that approximately one-quarter of the world’s population has been infected with TB bacteria, but only about 5–10% of infected people eventually develop TB disease. TB Infection vs Active TB Disease Feature TB Infection Active TB Disease Bacteria present Yes Yes Symptoms Usually absent Often present Feeling ill Usually no Often yes Can spread TB? Generally no Pulmonary/laryngeal TB can be infectious Treatment Preventive treatment may be recommended Requires multidrug treatment Main concern Future progression to disease Illness and possible transmission This distinction is one of the most important things to understand about Tuberculosis. A positive TB infection test does not automatically mean that someone has contagious active TB. What Causes Tuberculosis? The immediate cause is infection with Mycobacterium tuberculosis. But developing active TB is influenced by more than exposure alone. The body’s immune defenses play a major role in determining whether bacteria remain contained or multiply and cause disease. Factors associated with a higher risk of developing TB disease include: WHO specifically identifies weakened immunity, diabetes, undernutrition, tobacco use and harmful alcohol use among important risk factors. A Useful Way to Think About TB Think of TB infection as a battle between the bacteria and the immune system. If the immune system successfully contains the bacteria, a person may remain well for years. If immune defenses weaken or the bacteria overcome containment, TB disease can develop. That’s why a person’s risk can change over time—even if the original exposure happened years earlier. Symptoms of Tuberculosis TB symptoms can develop gradually, which is one reason the disease may go unnoticed. Common Symptoms of Pulmonary TB Typical symptoms include: According to WHO, symptoms may be mild for many months. This delay can allow an infectious person to continue transmitting the bacteria before TB is recognized. TB Beyond the Lungs Tuberculosis does not always stay in the respiratory system. It can affect organs such as the: Symptoms therefore vary depending on the organ involved. For example, TB affecting the spine may cause persistent back pain, while TB involving the brain can produce neurological symptoms. Extrapulmonary TB can be harder to recognize because its symptoms may resemble many other conditions. When Should You See a Doctor? Don’t wait for symptoms to become severe. Medical evaluation is particularly important if you have a prolonged cough accompanied by symptoms such as unexplained weight loss, fever, night sweats, chest pain or blood in sputum. You should also discuss TB screening with a healthcare professional if you have had close contact with someone diagnosed with infectious TB or have medical or social factors that increase your risk. A cough alone does not prove that someone has TB—many other respiratory conditions can cause similar symptoms. The important point is that persistent or concerning symptoms deserve evaluation. How Is Tuberculosis Diagnosed? Diagnosis usually combines clinical assessment with laboratory and imaging tests. WHO recommends rapid diagnostic tests as the initial tests for people with signs and symptoms of TB. Molecular tests can help identify TB and, depending on the test, provide information relevant to drug resistance. Depending on the situation, healthcare professionals may use: A TB skin test or blood test can help identify TB infection, but it does not by itself establish that a person has active TB disease. Active disease must be evaluated separately. Tuberculosis Treatment: Why Completing the Course Matters One of the biggest mistakes people can make is stopping TB medication simply because they start feeling better. TB treatment uses multiple antibiotics, because the bacteria can be difficult to eliminate and can develop resistance when treatment is inadequate. For drug-susceptible TB, commonly used medicines include: WHO notes that treatment commonly lasts around 4–6 months, depending on the disease and regimen. Current treatment recommendations are periodically updated as evidence changes. The exact medicines, doses and duration should be determined by a qualified healthcare professional. Why TB Treatment Must Be Taken Seriously Imagine treating a fire by extinguishing only the visible flames. The remaining embers could reignite. TB bacteria can similarly persist when treatment is incomplete or inappropriate. Poor adherence can contribute to treatment failure and drug-resistant TB. That’s why modern TB care emphasizes not only medicines but also patient education, adherence support and follow-up. WHO’s current treatment guidelines specifically address both drug-susceptible and drug-resistant TB alongside patient care and support. Drug-Resistant Tuberculosis Some TB bacteria