Definition

Tuberculosis (pronounced too-BUR-kyoo-LOH-siss), or TB, is a contagious disease of the lungs that can spread to other parts of the body and may be fatal. TB is caused by a microorganism known as the tubercle bacillus, or Mycobacterium tuberculosis. The disease can now be treated, cured, and prevented. However, scientists have never come closing to wiping it out and TB remains one of the most serious diseases worldwide.

Description

Some parts of the population are at higher risk of getting TB than others. For instance, tuberculosis is more common among elderly people. Typically, more than one-fourth of the TB cases reported in the United States occur among people above age sixty-five.

Elderly people are especially vulnerable for a number of reasons. First, the disease can take years to become active, so an older person may have gotten the disease earlier in life and only discovered it after...