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Fact Sheets

Anthrax is currently considered one of the most serious bioterrorism threats. Beginning in the second half of the 20th Century, B. anthracis was developed by several countries as part of their biological weapons (BW) programs, and autonomous groups have also demonstrated the intent to use the bacterium in acts of terrorism.
Botulinum toxins pose a major threat as biological weapons because they are extremely potent and lethal; some of the toxins are relatively easy to produce and transport; and people with botulism require prolonged intensive hospital care.
Glanders is caused by infection with the bacterium Burkholderia mallei, and melioidosis is caused by Burkholderia pseudomallei. Both have the potential to produce fatal disease and have been identified by the CDC as Category B biological agents. HHS has identified these diseases as top priorities for development of medical countermeasures.
Cyanide is a naturally occurring chemical, found in many plants, that has been used in conventional warfare and poisoning for 2 millennia. It is highly lethal, whether inhaled as a gas, ingested in solid form, or absorbed through topical exposure. Two notorious incidents in recent history—the Jonestown Massacre in 1978 and the Tylenol poisonings in 1982—highlight the lethality of this poison.
F. tularensis is considered to be a serious potential bioterrorist threat because it is one of the most infectious pathogenic bacteria known—inhalation of as few as 10 organisms can cause disease—and it has substantial capacity to cause serious illness and death. The bacterium was developed into an aerosol biological weapon by several countries in the past.
Some HFVs are considered to be a significant threat for use as biological weapons due to their potential for causing widespread illness and death. Because of their infectious properties, associated high rates of morbidity and mortality, and ease of person-to-person spread, Ebola, Marburg, Junin, Rift Valley fever, and yellow fever viruses have been deemed to pose a particularly serious threat, and in 1999 the HFVs were classified as category A bioweapons agents by the U.S. Centers for Disease Control and Prevention (CDC).
Nerve agents are a class of chemicals grouped together based on their common mechanism of action, which is interruption of vital nerve transmissions to various organs.
Pulmonary agents (also known as “choking” agents) compose a class of chemical compounds that disrupt normal breathing.
The CDC has classified ricin toxin as a Category B threat agent. Category B agents are the second highest priority agents because they can be disseminated with moderate ease, they cause moderate morbidity and low mortality, and they “require specific enhancements of CDC’s diagnostic capacity and enhanced disease surveillance.”
Although never employed as a bioweapon to date, R. prowazekii was studied as a candidate for airborne dissemination by Japan during World War II and by the former Soviet Union during the 1970s because of its potential lethality and its ability to spread between humans via lice. Typhus has the potential to produce fatal disease and has been identified by the CDC as a Category B biological agent.
Blister agents, also known as vesicants, are a class of chemical weapon first used in combat during World War I. The prototypical and most common blister agent is sulfur mustard (SM) (bis-(2-chloroethyl) sulfide), commonly referred to as mustard gas.
Smallpox is considered one of the most serious bioterrorist threats. It was used as a biological weapon during the French and Indian Wars, (1754 to 1767) when British soldiers distributed smallpox-infected blankets to American Indians. In the 1980s, the Soviet Union developed variola as an aerosol biological weapon and produced tons of virus-laden material annually intended for intercontinental ballistic missiles.
Plague is currently considered to be one of the most serious bioterrorism threats. Y. pestis was developed as an aerosol weapon by several countries in the past. Aerosol dissemination of bacteria would cause primary pneumonic plague in the exposed population, an otherwise uncommon, highly lethal, and contagious form of plague.