Tuberculosis (TB) is an infectious disease you get by breathing in bacteria that an infected person releases into the air, usually when they cough, speak, or sneeze.

What TB Is

  • TB is caused by a bacterium called Mycobacterium tuberculosis.
  • It mainly affects the lungs , but it can also reach the kidneys, spine, or brain.

How You Get TB

You “get” TB when you inhale tiny droplets that contain TB bacteria:

  • Someone with active TB in the lungs or throat coughs, talks, laughs, or sings, releasing microscopic droplets into the air.
  • If you are nearby and regularly breathe in this air over time, the bacteria can reach your lungs and cause infection.
  • Transmission is more likely in small, poorly ventilated indoor spaces (crowded homes, prisons, shelters, refugee camps, small rooms, closed vehicles).
  • People most at risk are those in close, prolonged contact with someone who has untreated active TB: family members, roommates, coworkers, classmates.

An example: living in the same small bedroom with someone who has untreated, coughing TB for weeks is far riskier than briefly passing them in a shop.

How You Do Not Get TB

TB does not spread like many everyday germs:

  • Not by shaking hands.
  • Not by sharing food, drinks, plates, or cutlery.
  • Not by touching bed linens or toilet seats.
  • Not by sharing toothbrushes or kissing.

The bacteria must be airborne and inhaled ; casual contact or touching objects is not enough.

Latent vs Active TB (Important Difference)

Once you breathe in TB bacteria, two main situations are possible:

  • Latent TB infection
    • Your immune system keeps the bacteria “asleep.”
    • You have no symptoms and feel fine.
    • You cannot spread TB to other people.
  • Active TB disease
    • The bacteria multiply and start damaging parts of your body, usually the lungs.
* You may get symptoms like cough (often long-lasting), fever, night sweats, and weight loss.

* If it’s in the lungs or throat and untreated, you **can** spread TB to others.

Active TB sometimes develops soon after infection, but it can also appear months or years later, especially if the immune system becomes weak (for example due to HIV, certain medications, undernutrition, or serious illness).

What Increases Your Risk

You are more likely to get infected or develop active TB if:

  • You live or work in crowded, poorly ventilated settings (prisons, refugee camps, overcrowded housing).
  • You spend a lot of time with someone who has untreated active pulmonary TB.
  • Your immune system is weakened (HIV infection, certain cancer treatments, long-term steroids, severe undernutrition, some chronic diseases).
  • You have chronic alcohol or drug misuse, or very poor general health and diet.

If You’re Worried You Might Have Been Exposed

Health authorities recommend you seek medical advice if:

  • You spent time in the same household or closed room with a person who has active TB , especially if they have been coughing for weeks.
  • You have symptoms like:
    • cough lasting more than 3 weeks
    • coughing up blood
    • chest pain
    • fever, night sweats, tiredness, or unexplained weight loss

Doctors can check for TB with:

  • A skin test or blood test (to look for infection).
  • A chest X‑ray and sometimes sputum (mucus) tests to see if there is active disease and if you are contagious.

TB is treatable and curable with the right antibiotics taken for several months, and starting treatment quickly greatly reduces the chance of spreading it to others.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.