Tuberculosis (TB) is an infectious disease that primarily affects the lungs, and the number of cases of TB is on the rise. Many people think of TB as a rare disease that only affects people in undeveloped countries, but that is not the case any more. Since the 1980s, the number of cases of TB has risen dramatically due to the spread of HIV, which is the virus that causes AIDS.
Whatís the connection? The HIV virus suppresses the immune system, making people who are HIV-positive far more vulnerable to tuberculosis bacteria. People with an HIV infection are significantly more likely than those who are not HIV-positive to get TB and have it lead to active disease.
Can I catch TB from someone who has it?
It is possible. Tuberculosis is a bacterial disease that can be spread from one person to another. You can catch tuberculosis through exposure to the bacteria in tiny droplets released into the air, which can happen when a tuberculosis patient coughs, sneezes, laughs or sings. However, itís not very likely youíll catch tuberculosis from a brief encounter with a stranger with TB. Itís more likely to happen if you live or work with someone with TB who has not yet been treated and with whom you have prolonged exposure. Most people who have had appropriate medication for tuberculosis for at least two weeks are not contagious any more.
Are some people at greater risk than others of catching TB?
While anyone can get tuberculosis, there are risk factors that can increase your chances of catching the disease. As mentioned above, one of the greatest risk factors is a weakened immune system. Your immune system may be compromised through HIV infection or other illnesses and drugs, including diabetes, end-stage kidney disease, certain cancers, immunosuppressant drugs (such as those used for transplant patients), malnutrition, and simply being very young or very old.
People located in certain geographic locations have a higher risk of acquiring TB than others. These locations include Sub-Saharan Africa, India, China, Mexico, the islands of Southeast Asia and Micronesia, and parts of the former Soviet Union.
Lifestyle factors also play a role, such as cigarette smoking and substance abuse, both of which weaken your immune system and leave you more vulnerable to TB. Working in a health care environment in which you are exposed to tuberculosis patients also increases your risk, and that can include working in prisons, nursing homes or immigration centers. Regular use of a mask and thorough hand washing can significantly reduce your risk of catching TB in these environments.
The problem of drug-resistant TB
Another important reason tuberculosis is on the rise and remains a significant killer is that tuberculosis bacteria have evolved over time, becoming stronger and more resistant to the antibiotics used as treatment. The first antibiotics were introduced over 60 years ago, and some TB bacteria have mutated into forms that are able to survive these antibiotics and continue to multiply. This antibiotic resistance gets passed on to future generations of bacteria, and over time the drug-resistant bacteria go on to become resistant to other antibiotics as well. This is one reason it is critically important to follow a doctorís instructions regarding the proper use of tuberculosis medication.
People with tuberculosis have to take a series of different medications over a period of many months in order to truly eliminate the disease. However, many people stop taking the medication when they begin to feel better, which is far too soon. Even though you may feel better, all of the tuberculosis bacteria are not yet killed. Those remaining bacteria survive and multiply, and are extremely difficult to kill, even with other antibiotics. Those bacteria then may spread to other people, which is why we are seeing an increase in TB infections in many places in the world, particularly the drug-resistant type. Strict control programs in the US have helped reduce the spread of TB in this country, but it remains a significant concern.