Tuberculosis (TB) is a potentially serious infectious disease caused by the TB bacteria (germ). TB usually affects the lungs but it can affect any part of the body. If left untreated, TB may be fatal.
Types of TB
There are two types of TB-related conditions: latent TB infection and active TB.
Latent TB infection – The TB bacteria have infected a person but aren't growing. The person is well, doesn't have any symptoms and doesn't spread TB bacteria to others. Many persons with latent TB never develop TB disease; however in some persons, especially those with a weakened immune system, the bacteria become active, multiply, and cause TB disease or active TB.
Active TB – The bacteria become active and start growing, causing symptoms usually making a person feel sick. People with active TB in their lungs or throat can easily spread the disease to others.
How TB spreads
The bacteria that cause TB are spread through tiny droplets released into the air when someone with active TB in their lungs or throat coughs, sneezes, sings or speaks and another person who is nearby breathes in the infected droplets into their lungs.
TB cannot be spread by touching surfaces, shaking hands or sharing objects.
The symptoms of active TB include:
- cough for 3 weeks or longer;
- pneumonia that does not improve with antibiotics;
- fever for more than one week;
- night sweats;
- coughing up blood;
- unexplained weight loss or loss of appetite;
- chest pain or shortness of breath;
If you have symptoms, speak with your health care provider.
Risk factors for TB
Risk of latent TB infection - contact with a person with active TB in their lungs or throat.
Risk of developing active TB increases with certain conditions, such as:
- AIDS or HIV infection;
- medication or medical conditions that weaken the immune system;
- chronic renal failure;
- some types of cancer;
- infection with latent TB within the last two years;
- being malnourished or underweight;
- cigarette smoking.
Diagnosis and treatment
There are two kinds of tests that are used to detect TB bacteria in the body: the TB skin test and TB blood test. A positive TB skin test or TB blood test only tells that a person has been infected with TB bacteria. It does not tell whether the person has latent TB infection or has progressed to active TB. A person who has symptoms requires other tests, such as a chest x-ray and a sample of sputum, to diagnose active TB.
Both latent TB infection and active TB can be treated. Persons with latent TB infection and who are considered at high risk for developing active TB are often prescribed treatment to prevent them from progressing to active TB. All persons with active TB are prescribed treatment to cure their disease.
For more information on TB symptoms, how it spreads, who is at risk, testing and treatment and how TB can be prevented, visit HealthLine Online.