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Latent Tuberculosis Infection (LTBI)

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Latent TB Infection

Tuberculosis (TB) is caused by a bacteria called Mycobacterium tuberculosis.

These bacteria or germs can be spread by someone with active TB disease in the lungs (pulmonary TB). If a person with pulmonary TB coughs, shouts or sneezes, the TB germs are dispersed into the air. Anyone in close, prolonged contact with this person may inhale the TB germs into their lungs, which may spread to the rest of their body.

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Once the TB germs enter the body, they may live in the body without making the person feel unwell. This is because the body's defence system is able to fight against TB germs and keep them under control. Therefore, these germs in the body are inactive.
Persons infected with inactive TB germs are known to have Latent TB Infection (LTBI), not TB disease. Therefore, they feel well, their chest X-ray is normal and they will not spread the germs to others.

What Happens to Someone With Latent TB Infection?

Although the TB germs are inactive, they are still alive. Over time (may be years later), these germs may become active and multiply before attacking and damaging the lungs or other parts of the body (e.g. kidneys, brain or bones), resulting in TB disease.

If you have been identified to have close contact with an infectious TB patient, it is important for you to undergo screening.

In contrast to people with Latent TB Infection, persons with TB disease will feel sick and are able to spread the germs to others. They need to seek medical treatment early.

How do You Know if You Have Latent TB Infection?

To find out if you have Latent TB Infection, a blood test can be done for adults and a skin test for children less than two years old.

The doctor or nurse will inform you if you have been tested positive for Latent TB Infection.

What Can Be Done to Prevent Latent TB Infection from Turning into TB Disease?

If you have Latent TB Infection, it is possible to take medication to prevent yourself from getting TB disease. This is known as preventive treatment. By taking medications, you can kill the TB germs in your body before they become active and cause TB disease in the future.

Not everyone will benefit from preventive treatment. The doctor or nurse at TBCU will advise if it is beneficial for you to take preventive treatment.

Rifampicin (RIF) and Isoniazid (INH) are anti-TB medications used in preventive treatment and are prescribed for four (for RIF) or six (for INH) months. Your doctor or nurse will explain what side-effects to look out for when you are on RIF or INH .

It is very important to take your medication as prescribed by the doctor and return regularly for your check-up. This ensures that you are well and not experiencing side-effects from the medication.

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