Tuberculosis (TB) is a contagious infectious disease caused by a bacterium called Mycobacterium tuberculosis. TB most commonly affects the lungs, where it is known as pulmonary tuberculosis, but the infection can also affect other parts of the body, including the lymph nodes, kidneys, bones, spine, brain, and other organs.
Tuberculosis spreads through the air when a person with active pulmonary or throat TB coughs, sneezes, speaks, or sings. Tiny infectious particles can remain suspended in the air, particularly in enclosed or poorly ventilated spaces. A person does not usually get TB simply by touching someone who has the infection or by sharing food and household objects.
After exposure to TB bacteria, some people develop latent TB infection. In latent TB, the bacteria remain in the body but are not actively multiplying, and the person does not have symptoms or spread TB to others. However, latent TB can become active later, particularly when the immune system becomes weakened.
Active TB can cause serious illness if it is not treated. Common symptoms of pulmonary TB include a cough lasting several weeks, chest pain, fever, night sweats, tiredness, weight loss, and loss of appetite. Some people may cough up blood, especially when the disease has caused significant lung damage.
TB remains an important global health concern, but it is preventable and treatable. Modern combinations of antibiotics can cure most cases when the correct medicines are taken consistently for the recommended duration.
Diagnosis may involve a TB skin test or blood test for TB infection, chest X-rays, sputum testing, and other laboratory investigations. Doctors may use molecular tests to detect TB bacteria and identify possible drug resistance.
Treatment depends on whether TB is latent or active and whether the bacteria are resistant to standard medicines. Active TB usually requires several medicines taken together for several months. Completing treatment is extremely important because stopping medicines early can allow the bacteria to survive and become drug-resistant.
Tuberculosis is caused by Mycobacterium tuberculosis, a slow-growing bacterium that can survive inside the human body.
TB is mainly spread through the air.
When a person with infectious pulmonary or laryngeal TB coughs, sneezes, talks, laughs, or sings, bacteria-containing particles can be released into the air.
Another person can become infected by breathing in these particles.
The risk of transmission is higher during prolonged close contact, particularly in crowded or poorly ventilated environments.
People living in the same household as someone with infectious TB may have a higher risk of exposure.
Healthcare workers and others who regularly care for people with active TB may also have increased exposure risk.
A person with latent TB infection does not normally spread the bacteria to other people.
Not everyone who inhales TB bacteria develops active disease. The immune system can contain the bacteria and keep them inactive.
Latent TB can become active later if the immune system becomes weakened.
Conditions such as HIV infection, diabetes, certain cancers, severe malnutrition, or treatment with immune-suppressing medicines can increase the risk of TB becoming active.
Smoking and heavy alcohol use can also increase the risk of developing TB disease.
TB is not normally spread through shaking hands, hugging, sharing food, drinking from the same glass, or touching surfaces.
The bacteria can affect the lungs most commonly, but they may spread through the bloodstream or lymphatic system to other parts of the body.
Drug-resistant TB develops when TB bacteria survive medicines that are normally used to treat the infection. This can happen when treatment is not taken correctly, medicines are interrupted, or resistant bacteria are transmitted from another person.
Drug-resistant TB requires specialized treatment and careful medical supervision.
TB prevention involves early diagnosis, effective treatment, vaccination in appropriate settings, and reducing exposure to infectious respiratory particles.
The BCG vaccine is used in many countries, particularly to protect children from severe forms of TB. Its use and vaccination schedules vary by country.
People who have been exposed to someone with infectious TB should follow medical advice about testing.
TB skin tests and TB blood tests can help identify TB infection.
People with latent TB may be offered preventive treatment to reduce the chance of developing active disease.
Early identification and treatment of active TB is one of the most important ways to prevent transmission.
People diagnosed with infectious pulmonary TB should follow healthcare and public health instructions about staying home or using respiratory precautions until they are considered less infectious.
Good ventilation can reduce the concentration of infectious particles in indoor spaces.
Avoiding overcrowded and poorly ventilated environments can reduce exposure risk.
Healthcare workers and others caring for people with infectious TB should use appropriate protective measures.
People with conditions that weaken the immune system should discuss TB screening with their healthcare provider when appropriate.
Maintaining good nutrition and managing conditions such as diabetes can support overall health and reduce some risks associated with TB.
Smoking cessation can improve lung health and reduce respiratory disease risks.
TB remains a serious infectious disease, but early diagnosis and complete treatment can save lives and prevent transmission. Persistent cough, fever, night sweats, unexplained weight loss, or coughing blood should be evaluated by a healthcare professional, particularly in people who have been exposed to TB.
One of the most important facts about tuberculosis is that infection does not always mean active disease. A person can have latent TB without symptoms and without spreading the infection. Testing can help identify people who may benefit from preventive treatment.
Active TB requires a full course of multiple antibiotics. Completing treatment exactly as prescribed is essential for successful recovery and for preventing drug-resistant TB.
With appropriate medical care, monitoring, infection-control measures, and preventive strategies, TB can be controlled effectively. If you or someone close to you has symptoms suggestive of TB or has been exposed to a person with active TB, professional medical evaluation is important rather than delaying testing or treatment.
Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider. In an emergency, call emergency services immediately.