Danger Level: Medium

What is it?

Tuberculosis (TB) is an infectious disease that affects mostly the lungs, but can affect other organs as well.

Who gets it?

A common misconception is that tuberculosis is a rare disease that no longer exists. You’d be surprised to know that about 8.5 million (!) new cases of tuberculosis occurred worldwide in 2005. Even though most of them were in developing countries (in Asia, Africa, the Middle East and Latin America), it also exists in the United States: in 2005 there were almost 15,000 new cases.

In the United States the disease can be mainly seen in immigrants and in HIV infected people. But anyone get be infected by it.

What causes it?

Tuberculosis is caused by germ called mycobacterium tuberculosis. You can see its picute s here -

You get infected by it from other infected people: when they cough, sneeze, or just speak, tiny droplets containing the germ make their way through the air. When inhaled, these droplets can infect the person inhaling them. It’s important to note that not every encounter with an infected person will get you infected: It depends on the duration of exposure and other things. For instance – when seated together with an infected person in a crowded, poorly ventilated place (such as airplanes) the risk is much higher.

How does it feel?

The disease has 2 stages:

1. Primary disease: When the germ first gets into your lungs, it seats at their middle and bottom and in most cases does not cause a disease. (The chances are higher in children or HIV infected people for a disease at this stage).

2. Secondary disease: The germ “sleeps” for years in the lungs, and can one day “wake up” to cause a disease. This time it goes to the top of the lung, where there is more oxygen. At this stage there are fever, night sweats, weight loss and lack of appetite and weakness. After a while cough develops with or without blood in it, and difficulty breathing can develop.

At this stage the disease can also spread to other organs of the body, like lymph nodes, the lung coverings, the urinary organs, the skeleton and even the brain.

If not treated, 1/3 of the patients will die within 1 year.

How is it discovered?

Tuberculosis is discovered in a number of ways:

1. Chest X-Ray: Will show round cavitations – those are hole-like wounds in the lungs, shown at the top of the lungs.

2. Identification of the germ: It can be identified by a microscope or when grown in a culture (a special environment it likes).

How is it treated?

There are a few antibiotic drugs that work against the germ causing tuberculosis. In order for that persistent germ to go away for good, treatment requires use of 4 different drugs together, taken for about 6 months. That’s because the germ is hard to reach and because using  less than 4 drugs will cause it to be resistant to treatment.

What about people who think they have been infected? Should they get treatment too?

In order for them to know if they indeed were infected, a test is performed, called a PPD skin test. If it is positive, it means you have been infected and should be treated for TB. In these cases only one of those drugs is enough, for 9 months.

You can see in this video how it’s done:

What happens after treatment?

If people stick to the treatment, usually they are cured of the disease by the end of it.

The best way to avoid it is by avoiding contact with people who have tuberculosis. If you know anyone with TB you should encourage them to seek treatment, so that they won’t be a threat to others. 

There is also a vaccine against TB called BCG. The problem is that it’s not always efficient, and it is only recommended in countries in which TB is more common.

What next?

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