Proliferation of Weapons of Mass Destruction (WMD) - Biological Weapons

Certain biological organisms and toxins have been developed as weapons that can be used against humans, livestock, and crops. Biological weapons are different from their chemical counterparts because they use living organisms or their products—viruses, bacteria, or toxins—such as ricin (which is derived from the castor bean) or mycotoxin (which is produced by fungi). Biological weapons attack a target by causing a deadly disease via inhalation, injection, ingestion, or entry through the skin into the body. They can be delivered through a variety of means, including bombs, warheads, sprayers, and individual delivery. Figure 3.2 shows the nations possessing or suspected of developing biological weapons as of 2004.

Depending on the agent, the incubation period for biological agents, or the time span between exposure and the first appearance of symptoms, can vary from a few hours to weeks. When it comes to weaponizing biological agents, certain characteristics make some organisms more ideal than others. These include the agent's ability to reliably infect, its contagiousness (whether or not it will spread easily from one person to another), stability, incubation time, ease of transportation, resistance to common antibiotics, and virulence (lethality). Weaponizing biological agents can be difficult because it is important to keep the pathogen alive and virulent through the delivery process and to make sure that the size of the agent is just right for optimum delivery.

Common Classes of Biological Weapons Agents

BACTERIA. Bacteria are single-celled organisms that can vary in lethality. Common bacteria used in biological weapons include Bacillus anthracis (causes anthrax), Vibrio cholerae (causes cholera), Yersina pestis (plague bacteria), and Francisella tularensis (causes tularemia). The bacterial incubation period is usually a few days.

RICKETTSIAE. Named after Howard Taylor Ricketts, the American pathologist who first identified them, rick-ettsial organisms are similar to bacteria, except that they exist within the intracellular environment and reproduce only in animal tissue. Rocky Mountain fever, Q fever, and typhus are all diseases caused by rickettsiae.

VIRUSES. Small in comparison with bacteria, viruses are also intracellular parasites and can affect plants and animals alike. Some diseases caused by viruses include smallpox, encephalitis, Ebola, yellow fever, lassa fever, and Venezuelan equine encephalitis.

TOXINS. Toxins differ from the other classes in that they are poisons produced by living organisms rather than living organisms themselves. Toxins may be proteins or nonproteinacious in nature, and they act by disrupting nerve impulse transmissions or blocking protein synthesis. Examples of toxins include Clostridium botulinum (causes botulism), found on poorly preserved food; Ricinus communis (ricin), found in the castor bean seed; and saxitoxin, found in certain shellfish.