Why Was Anthrax Used For Bioterrorism?

Mankind must put an end to war before war puts an end to mankind” – John F. Kennedy

Since the beginning, man has been inclined towards war to satisfy his various desires of power, food, dominance….and did I mention power? As we have progressed as a species, so too has our weaponry. The second world war brought a whole new dimension with the advent of the atomic bomb.

As our knowledge about humans, nature, physics, and chemistry have increased, so have their applications in causing, preventing and containing collateral damage. The introduction of bioweaponry was another such invention. Similar to nuclear energy, it has the power to lay waste to millions of lives, without being as physically violent. It could even be called a silent killer.


This word is a composite of 2 words – biological and terrorism. It’s the newest form of terrorism and employs biological agents. Diseases have ravaged humanity since our species developed, as even the strongest of us are mere mortals, exposed and helpless in the face of such potentially fatal threats. This is the basis of bioterrorism.

Technically, it is the intentional release of a virus or any disease-causing organism with the intent of harming humans, plants or livestock. Unlike other forms, however, it is not easy to contain the damages caused by these agents.

Caution Biowarfare

Bioterrorism is very harmful. (Photo Credit : Armed Science)

The concept of bioterrorism has been used in numerous movies, highlighting its disastrous effects. For instance, Resident Evil centers on a fictional virus, known as the T virus, which converts people into flesh-eating”undead” creatures. The virus spreads across the planet, destroying human life. Another movie, World War Z, spoke of a similar concept.

Bioterrorism has been used in the past, for instance, in the USA. Certain biological agents and toxins have been designated as Tier 1 because of the potential damage they can cause when misused. One such organism falling into this category is Bacillus anthracis.

Bacillus anthracis

It is a gram-positive, rod-shaped, spore-forming bacteria that causes anthrax. It can affect humans, wild animals and ruminants, but especially affects wild and ruminant animals. It has certain attributes that make it a fitting inclusion in the Tier 1 category. Most bacteria have certain structures, or properties, known as virulence factors, and B. anthracis is no exception. These factors are any property of a bacteria that help it in causing diseases and avoiding detection by the host body.

Bacillus anthracis spores

Bacillus anthracis spores. (Photo Credit : Pixnio.com)

B. anthracis has a capsule around it, which is a polysaccharide layer that helps the bacteria avoid detection by the immune system of its host. Apart from this, the bacterium produces 3 types of chemicals, namely a protective antigen, edema factor and lethal factor. Individually, these toxins are weak, but together, they make the bacteria very dangerous.

The protective antigen helps in neutralizing the antibodies created by the host. The edema factor provides a boost to the virulence factors, while the lethal factor is the actual toxin that brings about the death of our cells. Another very important virulence factor is the formation of spores. B. anthracis spores are capable of surviving in the soil for decades, which makes it deadly and difficult to prevent, in certain cases.


Anthrax is a rare disease that usually affects livestock. There have been very few documented instances of human infection, except when it has been used as a bioweapon. Although it can be fatal, it is non-contagious. Human-to-human infections are extremely rare, if not unheard of.

Cutaneous and GI tract mode of entry

Cutaneous and GI tract mode of entry.

The spores lie dormant until they enter a suitable host that has conditions favorable for their reproduction. The main goal of the organism is to reproduce and kill the host to ensure its own survival. Based on its mode of entry into the host, the disease can be divided into 4 types – cutaneous, gastrointestinal, inhalation and injection. These types also differ in their outcomes, i.e., some are fatal while others aren’t.

Cutaneous anthrax can occur when the spores enter the host through a cut or break in the skin. This is the most common and least fatal type of infection. With proper treatment, it is completely curable, but if untreated, it can be fatal in 20% of cases. It presents as an ulcer with a black center or a group of itchy blisters.

Gastrointestinal anthrax occurs when the spores are ingested. This is due to consumption of undercooked, infected meat. It affects the whole GI tract, stomach and intestines. If left untreated, it can kill most of those who are affected, and if treated, 60% can survive. The symptoms include fever, chills, bloody diarrhea, nausea and bloody vomiting, throat ache, etc.

injection mode of entry and Inhalataion

Injection and inhalation mode of entry

Injection anthrax was recently discovered, and occurs when the spores are injected into the bloodstream. It was discovered in heroin abusers who presented with similar symptoms to cutaneous anthrax. However, these symptoms occurred in the deeper layers of the skin. The infection spreads faster, as it has been injected, and it is also harder to diagnose, as a number of other bacteria exhibit similar symptoms.

Inhalation anthrax is the most fatal of the lot. As indicated by the name, it occurs when the spores are inhaled. This can occur due to working in close proximity to animal hides, tanneries, slaughterhouses, etc. The infection starts with the lymph nodes in the chest and eventually spreads throughout the body. Patients who do not receive treatment have a 10-15% chance of survival, while treatment ensures a 55% chance of survival. The symptoms include breathing problems, nausea, bloody vomiting, stomach ache, shock, chest discomfort, dizziness, etc.

Bacillus anthracis was the first organism to be used as a bioweapon, due to its virulence factors and deadly nature. However, all bioterrorism is a deadly form of terrorism and can cause an astounding amount of damage to humans, plants and livestock alike. 


  1. Centers for Disease Control and Prevention (CDC)
  2. National Center for Biotechnology Information (NCBI) (Link 1)
  3. National Center for Biotechnology Information (NCBI) (Link 2)
  4. University of Connecticut (UCONN)
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About the Author:

Mahak Jalan has a BSc degree in Zoology from Mumbai University in India. She loves animals, books and biology. She has a general assumption that everyone shares her enthusiasm about the human body! An introvert by nature, she finds solace in music and writing.

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