What are bioterrorism agents?
Bioterrorism agents are living organisms, such as bacteria, viruses, or fungi, or toxins that are deliberately used to sicken and kill. They may be used by terrorists partially because of their psychological impact on the public and partially because they can be deadly, are easy to distribute, are a relatively inexpensive weapon, and are difficult to detect. Bioterrorism agents have been used in acts of warfare for thousands of years. This has included dipping arrows into toxins, poisoning food and water supplies, and deliberately spreading deadly infections. Bioterrorism agents can be carried in food products, dispersed into the air or drinking water, introduced into crops and livestock, or even sent through the mail as was done in the U.S. in 2001.
Most potential bioterrorism agents are natural substances or microorganisms that normally cause a small number of deaths each year and/or during periodic outbreaks. They enter the body primarily by being inhaled into the lungs, ingested, through breaks in the skin, or through contact with the mucous membranes of the eyes and nose.
Agents may be genetically altered by those seeking to use them as a weapon. They may be concentrated, made easier to disperse (aerosolized), made more likely to infect, and/or made more resistant to treatment. Some agents cause infections that can be passed easily from person-to-person and would need to be quickly contained, while others, such as anthrax, typically affect only the person exposed but can be deadly without prompt treatment.
The Centers for Disease Control and Prevention (CDC) identifies potential bioterrorism agents according to the risk they pose to the public. The table below gives examples of select agents and toxins. For more information, see the CDC Select Agents and Toxins List.
|Botulism||Clostridium botulinum toxin||Bacterial toxin|
|Plague, Pneumonic||Yersinia pestis||Bacteria|
|Viral Hemorrhagic Fevers||Arenaviruses (Lassa, Machupo)
Bunyaviruses (Congo-Crimean, Rift Valley)
Filoviruses (Ebola, Marburg)
|Ricin Toxin||From Ricinus communis||Toxin from castor beans|
|Viral Encephalitis||Eastern equine encephalitis
Western equine encephalitis
Venezuelan equine encephalitis
For more specific information on agents of bioterrorism and emergency preparedness plans the U.S. government has in place in the event of another bioterrorist attack, visit the CDC's bioterrorism web site.
In addition to biological agents, chemical and radioactive agents may also be used as weapons of terrorism. An example of the use of chemical agents by a terrorist group occurred in 1994 and 1995 when the Aum Shinrikyo cult released the nerve gas sarin into the air in Japan, resulting in 19 deaths and thousands of people injured. An example of a radioactive agent is polonium 210, which in 2006 was the cause of death of Russian dissident, Alexander Litvinenko. For more on these agents, see the CDC webpage Preparing for and Responding to Specific Hazards.