Bioterrorist agents

The CDC has focused its efforts on four pathogens that are potential bioterrorist agents Ebola, Marburg, Lassa, and South American VHP viruses. None of these is native to the United States, so an outbreak that epidemiologists cannot link to travel must raise suspicion of bioterrorism. Although person-to-person spread through the inhalational route in a typical outbreak situation is not common, a bioterrorist-released aerosol could cause an outbreak through inhalational exposure. 

The potential benefit of symptom-based recognition is that disease trends may be identified before laboratories begin to report positive cultures. Case-based surveillance networks operate throughout Europe and are capable of detecting bioterrorist agent threats. 

The anthrax bioterrorist attacks that followed the events of September 11th 2001 resulted in a renewed interest BadUus anthracis, the causative agent of this disease. Research has focused on the development of better vaccines than the one currently available. It has been estimated that the aerosolized release of 100 kg of anthrax spores upwind of Washington DC would cause mortalities of 130,000-3,000,000 [63]. Nonetheless, wild-type Bacillus anthracis is susceptible to conventional antibiotics, including penicillin, oxyfloxacin and ciprofloxacin. The problem lies not with the bacterial infection itself, but with three proteins released by the bacteria - protective antigen (PA, 83 kDa), lethal factor (LF, 90 kDa) and edema factor (EF, 89 kDa) -known as anthrax toxins [63]. 

Until October 2001, no deaths from bioterrorism were reported in the U.S. On September 11, 2001, after the attacks on New York City and Washington, the Centers for Disease Control recommended that the nation increase its surveillance for unusual disease occurrences or clusters, asserting that they could be sentinel indicators of bioterrorist attacks. As predicted, cases of anthrax were reported in Florida, New York City, the District of Columbia, and New Jersey. Over the years, it has become evident that not only is biological warfare attractive to governments, it is equally attractive to terrorist cells because the agents are relatively inexpensive and easy to make. 

In the aftermath of the September 11, 2001, terrorist attacks on the United States, by the first few months of 2002 the U.S. government dramatically increases funding to stockpile drugs and other agents that could be used to counter a bioterrorist attack. 

We have already seen that chemical terrorists or bioterrorists can be resourceful and creative in choosing their agents. Typical BW agents that have been studied and/or weaponized (i.e., prepared for a delivery device) in the past include those that are notoriously capable of infecting via aerosols and respiratory droplets. Terrorists will likely choose those BW agents that are easily found, cultured, grown, and weaponized for dissemination via some delivery device. 

However, Bacillus anthracis, the causative agent in inhalation anthrax, still remains the premier bioterrorist threat today. The Bacillus anthracis spore is nearly ubiquitous in nature and is not terribly difficult to isolate and grow. Being a spore former, the anthrax bacterium can withstand environmental stress while maintaining its virulence, as well as being hardy enough to withstand chemicals, UV light, and processes used in its weaponization. Finally, especially nowadays, the word anthrax alone strikes a fearsome chord in most people. 

We have already seen a case of large casualties that was due to food contamination with a bacterial agent, the 1984 attack by the Rajneeshee cult with Salmonella typhimurium, although no deaths were directly attributable to this hioterrorist attack. This type of assault—basically a crime of opportunity using food-borne bacteria—is probably the more likely type of bioterrorist event we may encounter in the future. 

We have already seen that chemical incidents are relatively quick-acting and limited, whereas biological incidents would take time before they are recognized for what they are. In general, one can consider a chemical release or attack to be a lights and sirens affair, that is, rapid response and (hopefully) expeditious treatment of casualties. In a bioterrorist event, however, people would be unlikely to know that they were exposed to an infectious agent or toxin until the first symptoms appear, at the very least several hours following the event. 

Little can be said with certainty as to what would actually happen, or how the public at large would respond in the event of a major chemical or bioterrorist attack. There is general agreement, though, that should a chemical or biological agent be used in a violent act, the effects of this kind of terrorism will extend far beyond its immediate danger to the public. It is, therefore, incumbent on every health care provider to understand all aspects of this threat and to train and prepare for an event all hope will never occur. 

A Bioterrorist Attack with viruses, bacteria or similar agents can affect people, animals or plants ( agroterrorism ). While agents such as anthrax affect only the targeted individuals, other, such as smallpox, can spread between individuals, reaching a much larger target. 

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