Page 1013 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

744 PART 5: Infectious Disorders

CHAPTER Biological Warfare TABLE 81-1 Categorization of Potential Biological Agents
81 Richard H. Savel Biological Agent Disease
Category A
Ariel L. Shiloh
Vladimir Kvetan Variola major Smallpox
Bacillus anthracis Anthrax
KEY POINTS Yersinia pestis Plague
Clostridium botulinum (botulinum toxin) Botulism
• Unlike other mass casualty events, mass exposure to a biological
agent is unlikely to be realized until cases start presenting and a Francisella tularensis Tularemia
https://kat.cr/user/tahir99/
high degree of suspicion is needed to realize this. Filoviruses and arenaviruses (eg, Ebola virus, Lassa virus) Viral hemorrhagic fevers
• Specific knowledge of the various types of agents is required to Category B
help in the diagnosis and management. Coxiella burnetii Q fever
• Victims of class A agents such as plague, anthrax, botulinum toxin, Brucella spp. Brucellosis
smallpox, and viral hemorrhagic fever are likely to be critically ill
and in need of the expertise of intensivists. Burkholderia mallei Glanders
• Preparedness for a mass casualty event is key in dealing with effec- Burkholderia pseudomallei Melioidosis
tive care of patients in the hospital setting, containment of spread Alphaviruses (VEE, EEE, WEE) Encephalitis
of particularly virulent organisms, and controlling public hysteria. Rickettsia prowazekii Typhus fever

Toxins (eg, ricin, staphylococcal enterotoxin B) Toxic syndromes
Chlamydia psittaci Psittacosis
Food safety threats (eg, Salmonella spp, Escherichia coli O157 : H7)
INTRODUCTION Water safety threats (eg, Vibrio cholerae, Cryptosporidium parvum)
Since the terrorist attacks of September 11, 2001, and the distribution Category C
of mail containing anthrax spores that led to seven deaths in the United Emerging threat agents (eg, Nipah virus, hantavirus)
States, the threat of a large-scale bioterrorist attack has become very real.
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A recent report by the Monterey Institute for International Studies found EEE, eastern equine encephalomyelitis; VEE, Venezuelan equine encephalomyelitis; WEE, western equine
a total of 121 biocrimes were committed since 1960, with a reported encephalomyelitis.
sharp rise since 1995. Reports of biological agent stockpiles and their Reproduced with permission from Rotz LD, Khan AS, Lillibridge SR, et al. Public health assessment of
2,3
weaponization by Iraq and the former Soviet Union, as well as the use of potential biological terrorism agents. Emerging Infect Dis. February 2002;8(2):225-230.
various biological agents by cult organizations such as the Rajneesh cult,
Aum Shinrikyo, and Minnesota Patriots, make the possibility of their use
by a rogue nation or nonmilitary organization a very real one. a cloud. This would require an agent to be aerosolized into droplets or
particle sizes of 1 to 5 μm in diameter in order to reach and be absorbed
Attack of a civilian target would cause a large number of casualties,
panic, and civil disruption. There would be a rapid overwhelming of via the alveolar bed. Particles >5 to 10 μm would be filtered out by or
deposited into the upper respiratory tract. However, many viruses like
public health facilities and capabilities. It is highly likely that many if
4,5
not the majority of patients would need some degree of critical care such influenza, viral hemorrhagic fevers, and smallpox can be infective at these
sites. Aerosol delivery of an agent would also give rise to unusual presen-
as a ventilator or hemodynamic support. Thus the critical care physi- 10
cian’s role could be a central one that depends on specific knowledge tations of diseases such as inhalational anthrax and pneumonic plague.
A bioterrorist attack through the contamination of food and water is
of the various agents, and preattack preparedness, the two cornerstones
in dealing with such a catastrophe. The main objectives of this chapter less likely for several reasons. Most category A agents are not transmit-
ted via food and water, while category B agents that can be transmitted
are to provide a concise review of individual agents likely to be used in
a bioterrorist attack, and focus on key issues related to the intensivist by these routes usually cause short-term vomiting and diarrhea with a
relatively quick recovery. Current water treatment methods effectively
in preparing to deal with such an event.
The Centers for Disease Control and Prevention’s strategic planning kill many biological agents and contaminating a water or food supply
workgroup categorizes biological warfare agents into groups A, B, and C, effectively would require large amounts of toxin and bacteria in order to
based on capability to cause illness or death, stability of the agent, ease
of delivery, ease of mass production, person-to-person transmissibility,
potential for creating public fear and civil disruption, and the ability of TABLE 81-2 Distinguishing Features of a Biological Attack
the public health systems to deal with such an attack. Category A agents A rapid rise and fall of the epidemic curve over a short period of time (a few hours to days)
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would have the greatest impact on public health and its infrastructure. Instead of the peaks and troughs seen in natural outbreaks, there may be a steady rise in cases
Category B agents would have less impact on the public health and its
infrastructure. Category C agents are least likely to impact on the public A disproportionate number of people seeking care for similar symptoms
health and include various emerging infectious agents. This list is not Large numbers of patients arriving from the same geographical area
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definitive and serves only as a guideline for preparation for a bioterrorist Large numbers of rapidly fatal cases
attack (Table 81-1).
Recognition of a bioterrorist attack would require prompt identifi- A lower attack rate in people who were indoors compared to those who were outdoors
cation based on typical clinical syndromes, since awaiting laboratory Appearance of an uncommon disease that has bioterrorism potential (eg, anthrax, plague,
confirmation of these otherwise rare illnesses might be delayed. Certain tularemia, botulism)
epidemiologic features peculiar to a bioterrorist attack help distinguish it Increased numbers of sick or dead animals
from a natural outbreak of disease as outlined in Table 81-2. 8,9
Because of the greater absorption surface area of the alveolar bed, a A large number of cases within 48-72 hours of an attack suggests a bacterial agent, while
biological weapon is more likely to be delivered via an aerosol spray or those presenting within a few hours suggests a toxic agent

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