Bacterial Agents Used for Bioterrorism

Jan K. Horn

In This Article

Abstract and Introduction

Background: Bacterial pathogens and their products are potential agents of biological terrorism and biological warfare. These agents can be deployed through simple aerosol delivery systems and thereby cause widespread disease and death.
Methods: This report is a review of bacterial species that have been employed for development of biological terrorism, relying on a system for classification of their threat developed by the Centers for Disease Control.
Results: Physicians must understand how to recognize early signs and symptoms caused by bacterial agents. Clinical findings often seen on presentation are emphasized along with a summary of therapeutic approaches.
Conclusions: Initiation of immediate therapy and supportive care provides the best chance for survival from these potentially lethal and devastating infections. A high index of suspicion must be maintained, especially in the setting of a sudden influx of cases with what are often relatively nonspecific symptoms.

Biological warfare (BW) incorporates the use of microorganisms or toxic products derived from microorganisms to inflict mass casualties in military and civilian populations. Biological terrorism (BT) adds an additional objective: to use the resultant mass hysteria to further destabilize the population.[1] This report will discuss the use of bacterial agents to accomplish widescale terrorism or warfare. For this discussion, bacteria are defined as unicellular organisms that contain a cell wall and will include the coccobaccili commonly known as Rickettsiae.[2] The agents that will be described in some detail consist of those widely believed to pose the gravest risks to society and the military. This report will not discuss the use of bacterial agents for contamination of food supplies or destruction of animals.

Bacterial agents have been deployed in BW throughout history. Plague was used as a BW agent during the siege of Kaffa (present-day Feodosia in Crimea) by the Tartars in 1346 when plague-infected corpses were hurled into the city and the subsequent epidemic contributed to the surrender of the city. Glanders was allegedly injected into U.S. horses and cattle destined for delivery to France by German agents in World War I. Listed in Table 1 are the six CDC Category A agents believed to pose the highest danger. Three of these are bacterial agents that will be discussed in this article: Bacillus anthracis, Yersinia pestis (plague) bacillus, and Francisella tularensis. In addition, Category B agents Coxiella burnetii (Q fever), Brucellae sp. (brucellosis), Burkholderia mallei (glanders), and Burkholderia pseudomallei (melioidosis) will be described. A recent review discussed the other Category A non-bacterial agents in addition to the bacterial Category A agents.[3] All of these agents have been or are currently stockpiled for BT and BW purposes. These organisms are particularly suited for these purposes based on the following properties: (1) they can be disseminated by aerosol to produce an inhalational form of the disease; (2) the organisms can be rendered stable in both liquid and dry forms within the aerosols and in some cases can remain active for a considerable period of time; (3) most civilian populations have not been exposed and would carry no natural immunity; (4) the infections that are produced carry very high morbidity and mortality; (5) with three agents, smallpox, plague and viral hemorrhagic fever, person-to-person droplet contact can occur, therefore demanding respiratory/contact precautions; (6) the diseases they produce are difficult to diagnose and treat, there being a wide range of other common diseases in the differential diagnosis; and (7) all have been previously developed for BW, with reliable and tested knowledge of transmission, methods of deployment and prevention already in place.


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