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Tuberculosis (TB) Frequently Asked Questions

Florida Department of Health - Hillsborough County

TB Basics

Please view this short video about how the body reacts to tuberculosis.

What causes TB?

TB is caused by a bacteria or germ.

How is it spread?

TB is spread through respiratory droplets carried on the air.

How long does it (TB) stay in the air?

The only studies done on the length of time TB stays in the air were done in controlled environments. We do know that TB can be removed from the air depending on air flow. Part of our investigation process takes this into account as we determine who should be tested.

What about in common areas like home, places of worship, or grocery stores?

TB is more likely to be transmitted in small, closed environments. In large buildings, especially those with good air flow, the chances of becoming infected are small.

What if I walked by a person with TB in a hallway, a sidewalk, or somewhere else in the community?

Sunlight kills the TB germ, so any outside activities are excluded for exposure consideration. Because of the way air flows throughout the buildings, we concentrate our contact investigations only on those people who have been in a closed environment with an individual who has active TB disease. There is a general rule that at least eight hours of close prolonged contact time must have occurred for someone to be in enough contact with a person with TB for spread of the bacteria to happen.

Is there cleaning that needs to be done when someone has been in a room or building that has active TB disease?

The TB germ must be breathed in to cause infection. Regular routine cleaning of rooms and buildings is all that is recommended.

Can TB be cured?

Yes, TB is treatable and can be cured. That is why we investigate to see who is exposed and offer them screening and testing. If someone is infected, there is a preventive treatment that can be offered to keep that person from getting sick.

What are the symptoms or side effects of TB?

The symptoms of TB include a cough lasting more than 3 weeks, night sweats lasting more than a week, unexplained weight loss, a productive cough, or coughing up blood. The “side effects” of TB may include fatigue or tiredness, shortness of breath, and chest pain or tightness.

What is the preventive treatment for TB?

Preventive treatment for TB consists of one anti-TB medication and one vitamin, taken daily, for nine months.

Is there a vaccine or prevention against TB?

There is no TB vaccine given in the United States. TB is not a common illness here; there is an average of <40 cases reported in Hillsborough County each year. That is <40 in a population of 1.2 million. Since TB is not common in the US, no vaccine is given. In 2003, the CDC recommended against routine testing for TB because it is no longer common. Nowadays we only test those who have a risk for TB, such as contact with a person with TB or moving to the US from a country in which TB is common. As mentioned above, if a person tests positive on the test for TB, then an assessment will be made to determine whether medication, and which medication, is appropriate.

What is “close prolonged contact”?

There is a general rule that at least eight hours of close prolonged contact time must have occurred for someone to be in enough contact with a person with TB for spread of the bacteria to happen.

Can I take TB home to my family?

Remember, only a person who is sick with TB disease can spread it. A person with infection (i.e., no symptoms) cannot spread the germ. By finding out who has infection, we can then see if any of them are sick. Until then, there is no need to be concerned about bringing TB home. Good hygiene, such as covering your nose and mouth when coughing or sneezing, washing hands well, and staying home when you are sick are the best preventive measures for all types of illnesses.

TB Testing

What does TB skin testing involve?

The TB skin test involves injecting a solution, called tuberculin, under the skin. In 2-3 days the area is checked to see if there is a reaction. This is the most common test used for TB.

What does TB blood testing (aka interferon-gamma release assay (IGRA) testing involve?

TB blood testing or IGRA identifies the presence of TB infection by measuring a person’s immune response. Unlike the skin test, only one visit is required to obtain the blood sample to test for reaction.


How does the Department of Health determine who should be tested?

TB has been around for a long time; so we know how it is spread, who is at-risk, and in what situations it is most likely to pass from one person to another. Part of our investigation is to apply this knowledge to determine who should be tested.

Other Health Factors

If I have underlying respiratory illnesses, like bronchitis or asthma, am I at greater risk?

No. Underlying health or medical conditions do not make TB infection more likely. However, if a person with an underlying health condition is infected they may be at higher risk for getting sick.

I am taking immune suppressive drugs, how does that affect me?

As with underlying illnesses, taking immune suppressive drugs does not make someone more likely to have been infected. If you are infected, we can recommend medical follow-up. You can also consult your doctor who is prescribing those medications.

I am pregnant or a family member is pregnant. Is testing safe for them?

If you are at-risk for exposure and are pregnant, it is safe for the testing to be done. If a pregnant woman is infected, we work with her obstetrician to make sure she is in good health for her and her baby’s safety. Generally, we wait to give preventive treatment until 3 months after the baby is born. If a pregnant person has not been exposed or in contact with the person who has TB, than no testing is indicated.

Disease Investigations

What is the process used by the Department of Health for disease investigations?

First, there are over 50 diseases and conditions that by Florida law are reported to the health department to investigate for public health purposes. Tuberculosis is one of those diseases. We receive reports from medical providers, hospitals, laboratories, and concerned citizens. Once a report is received, we begin an investigation to determine the facts and whether there is a true public health concern.

Second, we assure that if the reported person is infectious (which means they can spread TB to others), that they are isolated to prevent the spread of TB. Once they are non-infectious, they are cleared from isolation by the Department of Health.

Third, we talk to the person with TB to find out who they have been in contact with. Then, we create a list of people, places, and times of exposure so that if testing is indicated for others, we can start with those at highest level of exposure. We also determine the best time for testing these individuals. Sometimes we do baseline testing (tells us if people are already infected with TB before this recent exposure), sometimes we do testing at 8-10 weeks after the final exposure, and sometimes we do both; each investigation is different and dependent on the facts that we collect.

Lastly, whenever we test for TB, we expect to see some positives, but it does not mean that the infection was from the person with TB. Sometimes people tested positive because of a TB infection from a previous exposure. We compare all the information collected, analyze it, and then draw conclusions and additional recommendations as indicated.