Bacillus Anthracis

What Is Bacillus Anthracis?

Bacillus anthracis is the bacterium that causes anthrax. This organism is different from many other bacteria because it forms spores. In this form, it can lie dormant (asleep), but may come to life with the right conditions. Once the bacteria come to life, they can have deadly effects.

 

Bacillus Anthracis Spores

Bacillus anthracis is an aerobic (oxygen-requiring) bacterium that lives in soil and has developed a survival tactic that allows it to endure for decades under the harshest conditions. As mentioned, this form is called a spore. You can think of a spore as a protective cocoon with the active bacterium inside.

 

When Bacillus anthracis is in its spore phase, it can withstand extreme heat, cold, and drought and continue to survive without nutrients or air. When environmental conditions are favorable, the spores will germinate into thriving colonies of bacteria. For example, a grazing animal may ingest spores that begin to grow, spread, and eventually kill the animal. The bacteria will form spores in the carcass and then return to the soil to infect other animals in the future.

 

Bacillus Anthracis Toxin

While the spore form of Bacillus anthracis allows it to survive in any environment, the ability to produce toxins is what makes it such a potent killer. Together, the hardiness and toxicity make this bacterium a formidable bioterrorism agent. Its toxin is made of three proteins:

 

Protective antigen binds to select cells of an infected person or animal, and forms a channel that permits edema factor and lethal factor to enter those cells.

Once inside the cell, edema factor causes fluid to accumulate at the site of infection. Edema factor can contribute to a fatal build-up of fluid in the cavity surrounding the lungs. It can also inhibit some of the body's immune functions.

 

Lethal factor also works inside the cell, disrupting a key molecular switch that regulates the cell's functions. Lethal factor can kill infected cells or prevent them from working properly.

 

What Does Bacillus Anthracis Look Like?

Bacillus anthracis spores and bacteria do not have a characteristic appearance, such as a specific color, smell, or taste. They also cannot be seen with the naked eye.

 

What Does Bacillus Anthracis Infect?

Bacillus anthracis most commonly infects wild and domestic animals (cattle, sheep, goats, camels, antelopes, and other plant-eating animals), but it can also occur in humans when they are exposed to infected animals, tissue from infected animals, or when anthrax spores are used as a bioterrorist weapon. There are three types of anthrax seen in humans:

 

How Dangerous Is Bacillus Anthracis?

The Centers for Disease Control and Prevention (CDC) classifies agents with recognized bioterrorism potential into three priority areas (A, B, and C). Bacillus anthracis is classified as a Category A agent. Category A agents are those that:

 

 

Other Category A agents include: