Tuberculosis (TB) is a serious disease caused by a germ - a bacterium called Mycobacterium tuberculosis. It usually affects the lungs but can also affect other parts of the body such as the kidneys, spine and brain.

The main symptoms of TB include severe coughing, fever, weight loss and weakness. Tuberculosis is contagious. People who have TB disease (active TB) spread TB germs in the air. It is important that people with TB disease seek treatment immediately. Treatments against TB disease can cure the infection and prevent transmission to others.

How do you catch TB?

In most cases, TB is spread through contact, at work or at home, with someone with TB disease (active TB) who release the TB germs into the air through:

• coughing

• laughing

• sneezing

• singing

• playing a wind instrument (eg flute), or

• speaking.

The TB germs can stay in the air for several hours. Breathing in air contaminated with TB germs can bring these into our lungs. Most people have a strong immune system that fight against the TB germs. But there are people whose immune systems cannot fight the TB germs which may settle in their bodies – that is cause latent TB infection (inactive).

Are there other ways to get TB?

Yes. In rare cases, a baby may be born with TB. This is what is called congenital tuberculosis. Babies with congenital tuberculosis usually have the following symptoms two or three weeks after birth: lack of appetite, no increase in weight, coughing, drowsiness, irritability. They may also have a fever, have fluid in the ears or develop a rash.

Remember that the TB germs travel in air. They are not transmitted by:

• handshakes

• sharing a meal, a drink or utensils

• bedding or toilet seats

• sharing a toothbrush

• kisses.

What is latent TB infection (inactive tuberculosis)?

In latent tuberculosis infection, the TB germs in your body are alive but inactive. You do not have signs and symptoms of TB, you are not sick with TB and you are not contagious and cannot spread TB.

Untreated latent TB infection can get worse: you can develop TB disease (active TB). Latent TB infection can turn into active TB disease at any time. Once you have active TB disease, you may develop symptoms of tuberculosis, and spread TB to others.

Between 5 and 10% of people with latent TB infection will eventually develop active TB disease. People with weakened immune systems are most vulnerable.

Your immune system is the defense of your body against disease. Some factors may weaken the immune system include having another serious illness, having another infection (eg HIV), being very old, not eating enough healthy foods (malnutrition), or taking certain medications (eg, chemotherapy against cancer).

What should I do if I have latent TB infection?

If you have latent TB infection:

• Get treatment.

• Get tested for human immunodeficiency virus (HIV, the virus that causes AIDS). It is important to know if you have HIV, as this could increase your risk of developing active TB disease.