Tuberculosis (TB)
What is Tuberculosis (TB)?
Tuberculosis, often called TB, is a bacterial infection caused by Mycobacterium tuberculosis. This bacterium primarily attacks the lungs but can spread to other parts of the body including the kidneys, spine, and brain. TB spreads through the air when an infected person coughs, sneezes, or talks.
There are two types of TB infection. Latent TB infection means you carry the bacteria but have no symptoms and cannot spread the disease. Active TB disease means the bacteria are multiplying and making you sick, and you can spread it to others. About 5 to 10 percent of people with latent TB will develop active disease if left untreated.
TB was once a leading cause of death worldwide. Today, it remains a serious global health concern affecting millions each year. Early detection and proper treatment can cure TB and prevent its spread to others.
Symptoms
- Persistent cough lasting three weeks or longer
- Coughing up blood or mucus
- Chest pain or pain when breathing or coughing
- Unexplained weight loss and loss of appetite
- Fever and chills, often occurring at night
- Night sweats that soak clothing and bedding
- Extreme fatigue and weakness
- Shortness of breath
People with latent TB infection have no symptoms and feel completely healthy. Only active TB disease causes noticeable symptoms. You cannot tell by looking at someone whether they have latent TB infection.
Concerned about Tuberculosis (TB)? Check your levels.
Screen for 1,200+ health conditions
Causes and risk factors
TB is caused by breathing in Mycobacterium tuberculosis bacteria from an infected person. Your risk increases if you spend time with someone who has active TB disease. Close contacts like family members, coworkers, and friends face higher exposure. Crowded living conditions, healthcare facilities, and prisons can increase transmission rates.
Certain factors weaken your immune system and raise your risk of developing active TB disease. These include HIV infection, diabetes, severe kidney disease, certain cancers, and medications that suppress immunity. Smoking and heavy alcohol use also increase your risk. Young children and older adults have weaker immune systems and higher vulnerability. People who were born in or travel frequently to countries with high TB rates face greater exposure risk.
How it's diagnosed
TB diagnosis involves several steps depending on whether latent or active disease is suspected. Blood tests like QuantiFERON-TB Gold Plus can detect TB infection by measuring your immune response to TB bacteria. These tests show if you have been infected but cannot tell whether you have latent or active disease. Skin tests, called tuberculin skin tests or PPD tests, are another option that requires a return visit to read results.
If TB infection is detected, additional tests determine whether you have active disease. Chest X-rays can reveal lung damage from active TB. Sputum samples, the mucus you cough up, are examined under a microscope and cultured to find live bacteria. These specialized tests require evaluation by a healthcare provider. Talk to a doctor about TB testing if you have symptoms or known exposure to TB.
Treatment options
- Antibiotics are the primary treatment for both latent and active TB
- Latent TB infection typically requires one medication for 3 to 4 months or two medications for 3 months
- Active TB disease requires multiple antibiotics taken together for 6 to 9 months
- It is critical to take all medications exactly as prescribed, even after feeling better
- Stopping treatment early can lead to drug-resistant TB that is much harder to cure
- Proper nutrition supports your immune system during treatment
- Avoid alcohol and tobacco, which can interfere with healing and medication effectiveness
- Rest adequately and manage stress to support recovery
- People with active TB must isolate from others until no longer contagious, usually after 2 to 3 weeks of treatment
- Regular follow-up appointments ensure treatment is working and monitor for side effects
Frequently asked questions
Latent TB infection means you carry TB bacteria but have no symptoms and cannot spread the disease to others. Your immune system keeps the bacteria inactive. Active TB disease means the bacteria are multiplying, causing symptoms, and you can infect others. About 5 to 10 percent of people with latent TB develop active disease without treatment.
TB spreads through the air when someone with active TB disease coughs, sneezes, speaks, or sings. You can breathe in the bacteria and become infected. TB does not spread through handshakes, sharing food or drinks, touching surfaces, or kissing. Close contact over time in enclosed spaces poses the highest risk.
Anyone with TB symptoms or known exposure to someone with active TB should get tested. Healthcare workers, people living in crowded conditions, and those traveling to high TB prevalence countries should consider testing. People with HIV, diabetes, or weakened immune systems need regular screening. Your doctor can determine if testing is right for you.
A positive TB blood test means your immune system has responded to TB bacteria, indicating you have been infected. It does not tell you whether you have latent TB infection or active TB disease. Additional tests like chest X-rays and sputum cultures are needed to determine if the infection is active and contagious.
Yes, TB can be cured with proper antibiotic treatment. Latent TB infection requires 3 to 4 months of medication, while active TB disease needs 6 to 9 months of multiple antibiotics. Taking all medications exactly as prescribed is essential for a complete cure. Incomplete treatment can lead to drug-resistant TB that is much harder to treat.
The most common symptom is a persistent cough lasting three weeks or longer, sometimes producing blood or mucus. Other symptoms include chest pain, unexplained weight loss, fever, chills, night sweats, and extreme fatigue. If you experience these symptoms, especially a prolonged cough, see a doctor promptly for evaluation.
People with active TB disease are usually no longer contagious after 2 to 3 weeks of proper treatment. Before treatment or in the early treatment phase, they should isolate from others to prevent transmission. People with latent TB infection cannot spread the disease and are safe to be around. Always follow public health guidance for specific situations.
Maintaining a strong immune system helps prevent latent TB from becoming active disease. Eat a nutritious diet rich in fruits, vegetables, and lean proteins. Avoid smoking and limit alcohol consumption. Get adequate sleep and manage stress effectively. If you have latent TB, treating it with medication prevents progression to active disease.
TB bacteria grow slowly and can hide inside your cells where antibiotics have difficulty reaching them. Multiple medications are needed to attack the bacteria in different ways and prevent resistance. Six to nine months of treatment ensures all bacteria are killed, including dormant ones. Stopping early allows bacteria to survive and multiply, often developing drug resistance.
Untreated active TB disease can cause severe lung damage and spread to other organs including the brain, bones, and kidneys. It can be fatal in many cases. Untreated individuals continue spreading the bacteria to others. Even latent TB infection carries risk, as it can become active disease years later, especially if your immune system weakens.