Above: Image © hidesy, iStockphoto

Unfortunately, terrorism is often in the news. Usually, you hear about incidents involving guns and explosives. But there’s another type of terrorism called bioterrorism. Bioterrorists release biological agents like viruses or bacteria to kill people or make them sick, and to intimidate or influence the government.

One of the most common agents used in biological attacks is anthrax (Bacillus anthracis). This is because anthrax forms spores that can be stored for long periods. These spores can be transported and spread under conditions that would kill other biological agents.

Did you know? A rogue scientist is a person trained in scientific research but who rejects the ethical principles behind their work. The American lab worker who sent anthrax through the mail in 2001 is an example of a rogue scientist.

Anthrax in the mail

In 2001, anthrax was all over the news. White powder containing anthrax spores was sent through the mail in the US. A worker at an American biodefense lab sent envelopes to two politicians and several news outlets.

The spore-filled letters resulted in 22 people being infected with anthrax. Five of these people died. Because of these events, the US postal service now has a biohazard detection system. This system actively scans for anthrax being sent through the mail. The U.S. Department of Defense and the Government of Canada also have similar monitoring systems.

Did you know? In 1979, aerosolized anthrax was accidentally released at a military biology facility in Sverdlovsk, Russia. Seventy-nine people reported anthrax-related symptoms and 68 of them died.

Could anthrax be used in a large-scale terrorist attack?

In Season Two of the TV drama Criminal Minds, terrorists tried to release anthrax into the ventilation system of a shopping mall. Their goal was to kill the crowds of people gathered there. Could something like this really happen?

In theory, yes. But it’s pretty unlikely. To target large crowds, attackers would need to aerosolize huge amounts of anthrax spores, which means turning them into a spray. That would allow the spores to become and remain airborne. Aerosolization requires sophisticated laboratory equipment. A distribution system would also be needed, since B. anthracis is quite large and heavy for a bacterium.

Let’s say the terrorists had access to all of these things. Even if the anthrax managed to reach a human target, that human would have to inhale 10,000 spores (or more) in order to get infected. That is quite a lot!

Anthrax certainly has the potential to be dangerous. A U.S. government study estimated that if 100 kilograms of anthrax spores were released from an airplane above Washington DC, up to three million people could die. Fortunately, anthrax is not an easy weapon to use.

Weaponizing anthrax would require sophisticated villains with advanced scientific and technical training. They’d also need lots of money! In 1993, a Japanese terrorist group unintentionally demonstrated how difficult it is to weaponize anthrax. They tried multiple times to release anthrax spores in Tokyo. Not a single person got sick!

Did you know? Biological weapons programs are known to exist in a dozen countries, including Iran, Iraq, Libya, North Korea, and Syria.

What can be done about anthrax?

Even if the Japanese attacks did not succeed, the anthrax letters in the U.S. showed that anthrax can be used as a weapon. So what can be done to defend people against bacterial spores that can survive for long periods of time, even in extreme conditions?

Gamma irradiation—short-wavelength electromagnetic radiation—can inactivate anthrax. Of course, most people don’t have gamma irradiation machines sitting around their homes. So high school student Marc Roberge decided to tackle the problem.

Marc discovered a simple way to deactivate anthrax spores in envelopes. Iron your mail! His experiment showed that a regular household iron can be used to destroy all anthrax spores in a common postal envelope. Thanks to this experiment, he won his school’s science fair!

Bioterrorist attacks involving anthrax have occurred in the United States. They have also been been attempted elsewhere. However, anthrax has never been used as a weapon in Canada. Due to our cold climate, anthrax does not grow well in our soil, either. This means that your chances of coming into contact with anthrax are extremely low.

Learn More!

About anthrax infections:

Anthrax (2015)
Centers for Disease Control and Prevention

Cutaneous anthrax (2014)
Center for Disease Control

Gastrointestinal anthrax (2014)
Center for Disease Control

Inhalation anthrax (2014)
Center for Disease Control

B. Rauner, Illinois Department of Public Health

Anthrax - Effects of Heat, Cleaning Compounds and Chemical Disinfectants (2016)
Minnesota Department of Agriculture

About anthrax attacks:

How the post office sniffs out anthrax before it hits your mailbox (2013)
A. Tarantola, Gizmodo

FBI investigation of 2001 anthrax attacks concluded; U.S. releases details (2010)
J. Warrick, The Washington Post

Seventeen-year-old devises anthrax deactivator (2006)
NBC News

Anthrax recalls Tokyo’s time of terror (2001)
C. Scanlon, BBC

Rethinking the lessons of Tokyo (2000)
A. E. Smitheson, Ataxia: The chemical and biological terrorism threat and the US response

About scientific research on anthrax:

Bacillus anthracis (2003)
R. C. Spencer, Journal of Clinical Pathology 56

Gamma Irradiation Can Be Used To Inactivate Bacillus anthracis Spores without Compromising the Sensitivity of Diagnostic Assays (2008)
L.A. Dauphin, B.R. Newton, M.V. Rasmussen, R.F. Meyer & M.D. Bowen, Applied and Environmental Microbiology 74

Anthrax toxin complexes: heptameric protective antigen can bind lethal factor and edema factor simultaneously (2004)
R. A. Pimental, K. A. Christensen, B. A. Krantz, R. J. Collier, Biochemical and Biophysical Research 322

Technology Challenges in Responding to Biological or Chemical Attacks in the Civilian Sector (2003)
J.P. Fitch, E. Raber & D.R. Imbro, Science 302

Mira Okshevsky

Mira has a Master of Science in Marine Microbiology and a PhD in Nanoscience. She is currently a postdoctoral research fellow at McGill University, where she studies how bacteria stick together is communities called biofilms. In her free time, Mira enjoys exploring the coves and beaches of her home province of Newfoundland.

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