HIV/AIDS and tuberculosis
People with HIV/AIDs and weakened immune systems are at an increased risk from infections such as TB, or tuberculosis.
Because TB can takes advantage of a weakened immune system, it's called an opportunistic infection.
How you can get tuberculosis
The bacteria that cause tuberculosis travel through the air, such as in a cough or sneeze. But you are not likely to get the disease from a single exposure. And you can't get it from sharing dishes or utensils, or by touching someone who has it.
You are more likely to get tuberculosis from constant exposure to an infected person, such as someone with whom you work or live. You are likely to get tuberculosis in places with poor ventilation, or crowded conditions. If you are HIV-positive, discuss with your doctor whether it is safe to continue working in places like these:
- A hospital, clinic or doctor's surgery
- A nursing home
- A prison
- A shelter for homeless people
Types of tuberculosis infection
There are two types of tuberculosis infection, latent and active.
- If you have a latent infection, the germs remain in your body, but don't cause symptoms.
- If your immune system is weak, the germs can multiply and become active, causing symptoms and disease.
Active disease is more likely if you have HIV, especially if your CD4 count is under 200. (CD4 cells are a type of immune system cell.) However, active tuberculosis can happen no matter what your CD4 level is. If you are infected with both HIV and TB, you are at least 10 times more likely to develop active TB than someone without HIV.
These are other factors that can increase your risk of active tuberculosis:
Signs and symptoms of tuberculosis
These are common signs and symptoms of tuberculosis:
As soon as you know you have HIV, ask your doctor for a tuberculin skin test (Mantoux test). This involves your being injected with a substance called PPD tuberculin. If you have a latent TB infection, your skin will be sensitive to PFD tuberculin, and a hard red lump will develop at the site of the injection, usually within 48-72 hours of having the test. It can be difficult to diagnose tuberculosis for these reasons:
- If you've recently been infected with tuberculosis or if your immune system is very damaged, you may not test positive but still be infected.
- You may test positive, but have a related bacterial infection, not tuberculosis. You may need to have other tests to confirm whether you have active TB.
- Other tests you may need include:
- A chest X-ray, which produces a picture of your lungs.
- A TB smear test, where your doctor takes a sample of phlegm and examines it under a microscope for signs of bacteria.
- A sputum culture, which involves growing the bacteria to reveal signs of active tuberculosis.