In 1964, tuberculosis fell to number 18. In the late 1980s, there were about 25,000 cases, with an estimated 2,000 killed. Tuberculosis still poses a threat today - every year, more than 3 million people are affected worldwide. A person is infected by breathing in droplets of moisture with tubercle bacilli . When a person sneezes or coughs, droplets form inside.
Tuberculosis begins to develop.
At the beginning of a primary infection, tubercle bacilli is sucked into the tubes of the lung. As part of a body's defense mechanism, macrophages destroy, sometimes successfully, the tubercle bacilli . Some tubercle bacilli become stuck. The number of tubercle bacilli increases and then invade the body's tissue. The macrophages are overwhelmed and cannot control the numerous tubercle bacilli , which can break into the lung tube wall, blood vessel, and beyond.