Hesperian Health Guides

What Is TB?

TB is caused by a small germ, or bacteria. Once this germ enters a woman's body, she is infected with TB and will remain so, probably for life. Healthy people can usually fight off TB sickness, and only about 1 out of 10 persons infected becomes sick with TB in his or her lifetime.

a woman's chest, showing her two lungs
This is what the lungs look like inside the body.
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Sometimes, especially when someone has HIV, TB germs attack other body organs, the lymph nodes, or the bones and joints. This is called extrapulmonary TB.

But if a person is weak, malnourished, diabetic, very young or very old, or infected with HIV, the TB starts to attack her body. Usually this happens in the lungs, where TB germs eat holes in the tissue and destroy blood vessels. As the body tries to fight the disease, the holes fill with pus and small amounts of blood.

Without treatment, the body starts to waste away, and the person usually dies within 5 years. But a person infected with both HIV and TB may die in just a few months without treatment.

This page was updated:23 Oct 2019