Updated: November 21, 2017
Tuberculosis or TB is a contagious infection that usually attacks the lungs which is caused by a type of bacteria called Mycobacterium tuberculosis(MTB).
The bacteria that cause tuberculosis are spread from one person to another through tiny droplets released into the air through coughs and sneezes. It can also spread to other parts of the body, like the brain and spine.
Tuberculosis infection can be of two types: latent and active.
The bacteria remain in the body in an inactive state. They cause no symptoms and are not contagious, but they can become active.
The bacteria do cause symptoms and can be transmitted to others.
The main cause of TB is Mycobacterium tuberculosis (MTB). When a person with TB whose lungs are affected, coughs, sneezes, spits, laughs, or talks will spread it through the air. Although tuberculosis is contagious, it is not easy to catch. You are much more likely to get tuberculosis from someone you live with or work with than from a stranger. Most people with active TB who have received appropriate treatment for at least 2 weeks are no longer contagious.
Signs and symptoms of active TB include:
Tuberculosis can also affect other parts of your body, including your kidneys, spine or brain. Signs and symptoms vary according to the organs involved when TB occurs outside your lungs. For example, tuberculosis of the spine may give you back pain, and tuberculosis in your kidneys might cause blood in your urine.
Without treatment, TB can spread to other parts of the body through the bloodstream:
Certain factors can increase your risk of the disease. These factors include:
A healthy immune system often successfully fights TB bacteria. But people with compromised immune systems are most at risk of developing active tuberculosis because of low resistance of the body.
A number of diseases and medications can weaken your immune system, including:
The risk of contracting tuberculosis is higher for people who live in or travel to countries that have high rates of tuberculosis and drug-resistant tuberculosis. These include:
This weakens your immune system and makes you more prone to tuberculosis.
Using tobacco greatly increases the risk of getting TB and dying because of it.
You may lack access to the medical care needed to diagnose and treat TB if you receive a low or fixed income, live in a remote area, have recently immigrated to TB prone areas, or are homeless.
If you are in regular contact with people who are ill increases your chances of exposure to TB bacteria. Wearing a mask and frequent hand washing greatly reduce your risk.
People who live or work in prisons, immigration centers or nursing homes are all at a higher risk of tuberculosis. That is because in overcrowded and poor ventilation areas the risk of the disease is higher.
Refugees lives usually in crowded and unsanitary conditions. Weakened by poor nutrition and ill health they are at high risk of tuberculosis infection.