MICROORGANISMS USED AS BIOLOGICAL WEAPONS

Agents of bioterrorism are usually found in the hands of terrorists, scientists, and most of all some rogue nations. In the hands of the extremists, biological and chemical agents used for terrorism are unsafe and can be used with or without provocation to cause threat, economic panic, sickness, and death in a target human population. But these agents are controlled under international laws in the hands of the research organizations and governments or countries that have them in their weaponry. However, some countries (as experienced in recent times) can use these chemical and biological agents as offensives against their enemies even in the slightest provocation.

While biological weapons (made form microbes including bacteria, viruses and fungi) may not be stockpiled by governments of nations due to the ease in producing them, a handful of developed countries have stockpiles of chemical weapons (e.g. sarin and mustard gas) in their military hardware. Also, mischievous private organizations with good financial backings can also start and stockpile biological and chemical weapons, and these can be accessible to terrorists who use them to cause terror and death in human populations.

Thus, the Chemical Weapons Convention (CWC) to which many nations of the world (especially those with stockpiles of chemical weapons) are signatories to, and the United Nations Disarmament Act helps to restrict nations in possession of chemical and biological weapons from using them, and most importantly adhere strictly to the prohibition of their usage and constantly give themselves to international scrutiny in order to ensure that they are complying to laid down rules regarding these agents. Table 1 summarizes the distinguishing features of biological agents (i.e. microorganisms) which are usually used for bioterrorism attack by terrorists.

Virtually all biological agents pose one health risk or the other, but possessing them do not make them a hypothetical threat until they have been weaponized and distributed in actual fact to their target human or animal population. Though a plethora of microbes and their metabolic products (e.g. toxins) may meet the criteria of a weaponized biological agent and be regarded as one, the U.S.

Table 1. Summary of characteristics of selected bioterrorism agents

Agent	Incubation period	Person to person spread	Morbidity/mortality	Diagnosis*
B. anthracis	1-5 days	No	HIGH/HIGH	Culture/serology
Y. pestis	2-3 days	Yes	HIGH/HIGH	Culture/serology
F. tularensis	2-10 days	No	HIGH/LOW	Culture/serology
Brucella  spp.	5 days-two months	No	HIGH/LOW	Culture/serology
Botulinum toxins	1-5 days	No	HIGH/HIGH	ELISA or mouse inoculation for toxin detection
Variola virus	7–17 days	Yes	HIGH/HIGH	Detection via ELISA, PCR, or virus isolation
Viral hemorrhagic fever agents (e.g. Lassa virus and Ebola virus)	4 days–3 weeks	No	HIGH/HIGH	PCR, ELISA, serology, virus isolation
*ELISA = Enzyme-linked immunosorbent assay   PCR = Polymerase chain reaction

Center for Disease Control and Prevention (CDC) has deemed it fit to catalog recognized microbes of terror based on their potency and threat. According to the CDC, biological agents of terrorism are placed in three (3) priority categories based on initial public health efforts and the apparent threat of these agents.

These categories are:

• Category A biological agents

• Category B biological agents

• Category C biological agents

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