TB is spread through the air from one person to another. The TB germ are passed through the air when someone who is sick with TB disease coughs, laughs, sings, or sneezes. If you breathe air that has TB germs, you may get TB infection. This means you have only dormant (sleeping) TB germs in your body. These dormant germs are not making you sick, and you cannot pass these germs to anyone else.

If these dormant TB germs in your body wake up and multiply, you will get sick with TB disease.

TB can cause death if not treated with medicine.

To identify those who may have been exposed to M. tuberculosis, health care providers typically inject a substance called tuberculin under the skin of the forearm. If a red welt forms around the injection site within 72 hours, the person may have been infected. This doesn't necessarily mean he or she has active disease. People who may test positive on the tuberculin test include:

• Most people with previous exposure to M. tuberculosis.
• Some people exposed to bacteria related to M. tuberculosis.
• Some people born outside the United States who were vaccinated with the TB vaccine (see TB vaccine below) used in other countries.

If people have an obvious reaction to the skin test, other tests can help to show if they have active TB. In making a diagnosis, doctors rely on symptoms and other physical signs, the person's history of exposure to TB, and X-rays that may show evidence of M. tuberculosis infection.

The health care provider also will take sputum and other samples to see if the TB bacteria will grow in the lab. If bacteria are growing, this positive culture confirms the diagnosis of TB. Because M. tuberculosis grows very slowly, it can take 4 weeks to confirm the diagnosis. An additional 2 to 3 weeks usually are needed to determine which antibiotics to use to treat the disease.

*Source: NIAID

With appropriate antibiotic treatment, TB can be cured in most people.

Successful treatment of TB depends on close cooperation between patient and healthcare provider. Treatment usually combines several different antibiotic drugs that are given for at least 6 months, sometimes for as long as 12 months.

Some people with TB do not get better with treatment because their disease is caused by a TB strain that is resistant to one or more of the standard TB drugs. If that happens, their healthcare providers will prescribe different drugs and increase the length of treatment.

The Importance of Finishing the TB Medicine

People who do not take all the required medicines can become sick again and spread TB to others. Additionally, when people do not take all the prescribed medicines or skip times when they are supposed to take them, the TB bacteria evolve to outwit the TB antibiotics. Soon those medicines no longer work against the disease. If this happens, the person now has drug-resistant TB.

Some people have disease that is resistant to two or more drugs. This is called multidrug-resistant TB or MDR TB. This form of TB is much more difficult to cure.

Treatment for MDR TB

Treatment for MDR TB often requires the use of special TB drugs, all of which can produce serious side effects. People with MDR TB may have to take several antibiotics, at least three to which the bacteria still respond, every day for up to 2 years. Even with this treatment, however, between four and six out of ten patients with MDR TB will die, which is the same rate seen with TB patients who are not treated.

*Source: NIAID

TB is largely a preventable disease, and adequate ventilation is the most important measure to prevent its transmission in the community.

In the United States, healthcare providers try to identify people infected with Mycobacterium tuberculosis (MTB) as early as possible, before they have developed active TB. They will give infected people a medicine called isoniazid (INH) to prevent active disease. This medicine is given every day for 6 to 12 months. INH can cause hepatitis (inflammation of the liver) in a small percentage of people, especially those older than 35 years.

Hospitals and clinics take precautions to prevent the spread of TB, which include using ultraviolet light to sterilize the air, special filters, and special respirators and masks. In hospitals, people with TB are isolated in special rooms with controlled ventilation and airflow until they can no longer spread TB bacteria.

Tuberculosis Vaccine

In those parts of the world where the disease is common, the World Health Organization recommends that infants receive a vaccine called BCG (Bacille Calmette Guerin) made from a live weakened bacterium related to MTB. BCG vaccine prevents MTB from spreading within the body, thus preventing TB from developing.

BCG has its drawbacks, however. It does not protect adults very well against TB. In addition, BCG may interfere with the TB skin test, showing a positive skin test reaction in people who have received the vaccine. In countries where BCG vaccine is used, the ability of the skin test to identify people infected with Mtb is limited. Because of these limitations, U.S. health experts do not recommend BCG for general use in this country.

*Source: NIAID

The World Health Organization (WHO) estimates 11.4 million people worldwide are infected with both Mycobacterium tuberculosis (MTB) and HIV. The primary cause of death in those infected with body microbes is from TB, not AIDS. In the United States, health experts estimate about two out of ten people who have TB are also infected with HIV.

One of the first signs that a person is infected with HIV may be that he or she suddenly develops TB. This form of TB often occurs in areas outside the lungs, particularly when the person is in the later stages of AIDS.

It is much more likely for people infected with Mtb and HIV to develop active TB than it is for someone that is only infected with MTB. Fortunately, TB disease can be prevented and cured, even in people with HIV infection.

People infected with both MDR TB, and HIV appear to have a more rapid and deadly disease course than do those with MDR TB only. If no medicines are available, as many as eight out of ten people with both infections may die, often within months of diagnosis.

Diagnosing TB in people with HIV infection is often difficult. They frequently have disease symptoms similar to those of TB and may not react to the standard TB skin test because their immune systems do not work properly. X-rays, sputum tests, and physical exams may also fail to show evidence of MTB infection in people infected with HIV.

*Source: NIAID