Over time, some TB germs have developed the ability to survive despite medications. This is partly because people don't take their drugs as directed or don't complete the course of treatment. Drug-resistant strains of tuberculosis emerge when an antibiotic fails to kill all of the bacteria it targets. The surviving bacteria become resistant to that drug and often other antibiotics as well. Some TB bacteria have developed resistance to the most commonly used treatments, such as isoniazid and rifampin Rifadin, Rimactane.
Some TB strains have also developed resistance to drugs less commonly used in TB treatment, such as the antibiotics known as fluoroquinolones, and injectable medications including amikacin and capreomycin Capastat.
These medications are often used to treat infections that are resistant to the more commonly used drugs. A healthy immune system often successfully fights TB bacteria. However, several conditions and medications can weaken your immune system, including:. Your risk of getting tuberculosis is higher if you live in, emigrate from or travel to areas with high tuberculosis rates.
Areas include:. Without treatment, tuberculosis can be fatal. Untreated active disease typically affects your lungs, but it can affect other parts of your body, as well. If you test positive for latent TB infection, your doctor might advise you to take medications to reduce your risk of developing active tuberculosis.
Only active TB is contagious. If you have active TB , it generally takes a few weeks of treatment with TB medications before you're not contagious anymore. However, certain people are more susceptible to the disease than others. People with healthy immune systems are better able to defend themselves against the progression of tuberculosis infection into active TB disease, while those with weakened immune systems — for instance, people with HIV — are much more susceptible to actually developing active tuberculosis disease.
The longer you spend with someone who has contagious TB, the greater the likelihood that you'll catch the illness. But even if you are infected with tuberculosis, you may still never get sick. Less than 10 percent of people who have been infected with the tuberculosis bacteria go on to develop active tuberculosis disease.
If you have tuberculosis, it's very important to take all medications exactly as prescribed and avoid contact with others until you are no longer contagious. And people who are most susceptible to TB should take care to avoid those infected with the disease.
People nearby may breathe in these bacteria and become infected. When a person breathes in TB bacteria, the bacteria can settle in the lungs and begin to grow. From there, they can move through the blood to other parts of the body, such as the kidney, spine, and brain. TB disease in the lungs or throat can be infectious.
This means that the bacteria can be spread to other people. TB in other parts of the body, such as the kidney or spine, is usually not infectious.
That is why people who think they may be infectious, may often hold something over their mouth when they are near to other people.
People working in a health clinic may also for this reason sometimes wear a mask. People are not equally infectious. Generally it is only people with TB of the throat or lungs who are infectious. Also, the most important factor is whether someone is on effective TB treatment. TB treatment dramatically reduces the number of infectious droplets released by a person. In many countries the public is not very well informed, and there are many myths about how TB is passed on. As a result many people believe that TB is hereditary or can be spread through food or water.
In developing countries a major effect of the resulting stigma and discrimination can be the social isolation of patients, both within and outside of the family.
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