How does tuberculosis reproduce?

Tuberculosis (TB) is caused by a bacterium called *Mycobacterium tuberculosis*, which primarily affects the lungs. It can also spread to other parts of the body. TB is not directly transmitted from one person to another, but rather through the air. Here's how *M. tuberculosis* reproduces and spreads, leading to the development of tuberculosis:

Reproduction:

1. Binary Fission: *M. tuberculosis* reproduces asexually through binary fission. During binary fission, the bacterium makes an identical copy of its DNA (deoxyribonucleic acid), which contains the genetic instructions for growth and reproduction.

2. Budding: In addition to binary fission, *M. tuberculosis* can also reproduce through a process called budding. In budding, a small outgrowth or "bud" forms from the parent bacterium. This bud eventually detaches and grows into a new, fully functional bacterium.

3. Slow Growth: *M. tuberculosis* is known for its slow growth rate. It can take about 15 to 20 hours for the bacterium to complete one round of cell division, which is significantly slower compared to other bacteria. This slow growth rate contributes to the persistence of the infection and makes TB treatment a long process.

Transmission:

1. Airborne Transmission: TB spreads through the air when an infected person coughs, sneezes, or speaks, releasing tiny droplets that contain the *M. tuberculosis* bacteria. These droplets can remain suspended in the air for several hours.

2. Inhalation: When a healthy person inhales these droplets, they may become infected with *M. tuberculosis*. The bacteria can enter the lungs and start to multiply within the lung tissues.

3. Latent Infection: In many cases, the initial infection remains inactive, leading to a latent TB infection. During this stage, the person does not have any symptoms and is not contagious.

4. Active Disease: However, in some individuals, the latent infection can progress into active tuberculosis. This happens when the immune system is unable to control the growth and multiplication of *M. tuberculosis*. Active TB can cause various symptoms, including persistent cough, fever, night sweats, and weight loss.

It's important to note that not all people exposed to *M. tuberculosis* will develop TB disease. The risk of developing active TB depends on factors such as the strength of the immune system, the strain of the bacteria, and the duration of exposure.