Emergency Preparedness 16:
Biological Agents Portal
Biological Agents (Bacteria, Viruses, Toxins)
Several
attributes of biological agents make them appealing to terrorists: they
can be made cheaply, they are transported with ease, and they are the
most insidious of NBC agents (due to their incubation times and initial
nonspecific presentations), and they can cause large-scale mortality
and social disruption. The covert use of biological agents further
enhances the prospect of late identification of these extremely deadly
agents. These factors can influence terrorists to use bioagents instead
of nuclear or chemical agents.
The affected will seek medical care, and caregivers can be lulled into a false sense of security of treating an acute nonspecific febrile or viral illness. Surveillance and recognition of these attacks are problematic, and large numbers of fatalities can be predicted. The financial impact of a biological attack could be extreme: $26.2 billion per 100 000 people exposed to aerosolized anthrax.1
A new level of surveillance is key to decreasing morbidity, mortality, fear, and social disruption from a biological attack. However, successful management of large numbers of deadly infectious disease victims involves changes and adjustments to almost every aspect of how a facility operates internally and in the community. Issues of isolation and quarantine arise, especially when the agent is still unknown or the possibility of more than one agent exists.
Note that each professional stakeholder group (public health and surveillance, infectious disease and treatment) emphasizes its component to this multi-disciplinary challenge, and each may implicitly assume certain aspects (such as resources) that are not applicable to the rural facility. The key task for rural providers is to monitor all of the pertinent efforts of the groups that will affect your facility and adapt those modifications that are suitable to your situation. Given this caveat, several professional organizations have established templates for facilities to use which may be useful as a good starting or review point for the biological component of a facility’s readiness plan. (The Bioterrorism Readiness Plan from the Association for Professionals in Infection Control and Epidemiology is one example. See Vol III—EMP20 Additional References and Resources.
Potential Agents
These
agents can enter their victims via breathing, eating, or injection;
however, their ability to be dispersed as aerosols makes respiratory
presentations more likely if mass casualties are the terrorists’ goal.
The Centers for Disease Control (CDC) prioritizes agents into three categories2:
Category A includes high-priority agents that pose a risk to national security because they (1) can be easily disseminated or transmitted person-to-person, (2) cause high mortality with potential for major public health impact, (3) might cause public panic and social disruption, and (4) require special action for public health preparedness:
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Variola major (smallpox)
-
Bacillus anthracis (anthrax)
-
Yersinia pestis (plague)
-
Clostridium botulinum toxin (botulism)
-
Francisella tularensis (tularaemia)
-
Viral hemorrhagic fevers:
- Filoviruses:
- Ebola hemorrhagic fever
- Marburg hemorrhagic fever
- Arenaviruses:
- Lassa (Lassa fever),
- Junin (Argentine hemorrhagic fever) and related viruses
Smallpox and anthrax are of particular concern because they are hardy organisms that can be easily grown in large quantities.
Category B contains the second highest priority agents including those that are (1) moderately easy to disseminate, (2) cause moderate morbidity and low mortality, and (3) require specific enhancements of CDC's diagnostic capacity and enhanced disease surveillance:
-
Coxiella burnetti (Q fever)
-
Brucella species (brucellosis)
-
Burkholderia mallei (glanders)
-
Alphaviruses:
-
Venezuelan encephalomyelitis
-
Eastern and Western equine encephalomyelitis
-
Ricin toxin from Ricinus communis (castor beans)
-
Epsilon toxin of Clostridium perfringens
-
Staphylococcus enterotoxin B
A subset of Category B agents includes pathogens that are food and/or waterborne, and includes but is not limited to:
-
Salmonella species
-
Shigella dysenteriae
-
Escherichia coli O157:H7
-
Vibrio cholerae
-
Cryptosporidium parvum
Category C contains the third highest priority agents that include emerging pathogens that could be engineered for mass dissemination in the future because of (1) availability, (2) ease of production and dissemination, and (3) potential for high morbidity and mortality and major health impact. Preparedness for Category C agents requires ongoing research to improve disease detection, diagnosis, treatment, and prevention. As of 2002, Category C includes:
-
Nipah virus
-
Hantaviruses
-
Tick-borne hemorrhagic fever viruses
-
Tick-borne encephalitis viruses
-
Yellow fever
-
Multidrug-resistant tuberculosis
Management
Response to a biological attack includes:
-
Enhanced surveillance, detection, communication, and collaboration
-
Disease containment
-
Directed therapy, prophylaxis, and vaccines
-
Psychological management
-
Confirmation of bioagent(s)
1. Surveillance,
detection, communication, and collaboration.
Front-line
provider surveillance for early detection is key in responding to a
biological attack. Real-time data from primary care providers, school
nurses, emergency departments, labs, and pharmacists may help to
identify potential patterns suggesting an attack. Pattern recognition
is important because in theory many bioagents may be used in an attack.
Short of an overt attack with consistent evidence, uncertainty will
reign as to the nature of the attack. Once a biological attack is
suspected, mobilization of the biodisaster plan usually cannot await
lab confirmation of specific agent(s). Facilities should have easily
accessible information of the syndrome description of each of the
agents on the CDC’s lists, with emphasis on the Category A agents. (See
Symptom Recognition and Therapy Recommendations for CDC Category A
Bioagents, at the end of this portal.) As a generality,
most agents
initially
present in victims with an influenza-like prodrome (including
fever, chills, malaise, or myalgias) followed by one or more of four
syndrome patterns:
-
Rapidly progressive pneumonia
-
Fever with altered mental status
-
Fever with rash
-
Bloody diarrhea
Evaluate any outbreak as a potential attack instead of assuming it to be endemic disease. (Note: discarding old assumptions is a mindful task that is difficult.) Analyze its pattern epidemiologically. Suggestive epidemiological elements of a bioterror attack include:
-
Possible announcement of a bioterrorist attack;
-
An unusual (and/or sudden) increase in (large numbers of) people with similar stage presentations of high-risk syndromes suggesting common source of exposure;
-
High rates of illness, toxicity, and death;
-
Rapid increase (hours, days) of disease incidence in normally healthy people;
-
Clusters of victims from the same area;
-
Lower attack rates from people sheltered from typical community interaction;
-
Unusual time or pattern of an endemic disease;
-
Unusual geographic presentation of a disease;
-
Highly virulent strains of bacteria (more than might be expected); failure to respond to standard therapy; rapidly progressive disease; antibiotic resistance;
-
Any patient (single case) of any disease on CDC’s three categories; and
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Dead animals.
When a possible bioterrorist attack has occurred, numerous groups should be notified: 911 emergency dispatches, local and state departments of health, infection control personnel, first responders, law enforcement, and the FBI. A carefully conceived notification plan should be in place. A coordinated media plan that appropriately conveys accurate information and conserves limited medical resources should also be in place. Expect to provide advice on contagiousness and decontamination to the public. Prepare for these critical notification and education functions.
2. Disease
Containment
Efficient triage is an
important goal. The truly symptomatic victims need to be distinguished
from those who are ‘walking worried.’ If there are mass casualties and
resources are overwhelmed, the triage principle of greatest good for
greatest number directs critical resources to those with
better chances
of survival. Precautions to prevent transmission of disease to others
are based on the particular agent, which initially may not be known.
Modes of transmission include:
-
Contact: either direct or indirect (from contamination of the inanimate environment)
-
Droplet: large particles expelled from the naso/oropharynx (limited range)
-
Airborne: aerosolization of small particles of the infectious agent over long distances
See Vol III—EMP19 Patient Isolation Precautions for modes of transmission of bioterror agents. Take full precautions until it is reasonably clear which agent(s) are involved. This involves:
-
Knowing and strictly adhering to appropriate use of barrier technology (gloves, gowns, HEPA filter masks, shoe covers, protective eyewear) and infection control measures;
-
Using negative air pressure in treatment areas;
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Isolating possible infectious patients in single rooms with adjoining anterooms with proper equipment and hand washing capability;
-
Instituting quarantines when warranted;
-
Alerting personnel and departments about tasks that generate aerosols: lab centrifuges, autopsies, etc;
-
Utilizing special handling measures for specimens; and
-
Notifying funeral homes about any high-risk diseases from handling the dead.
Decontamination is usually not necessary unless victims are grossly contaminated such as direct exposure to powdered or sprayed biological agents. Clothing is placed in an impervious container with proper labeling (ID, contents, phone number) for law enforcement, and the victim is showered with soap and water. Environmental surfaces and equipment in direct contact with the bioagent can be cleansed with 0.5 percent hypochlorite (one part household bleach to 10 parts water).3
Post exposure prophylaxis and/or immunization depend on agent, type of exposure, and medical status of the victim. Access to current guidelines is critical in order to properly treat victims, conserve resources, and prevent adverse drug events. Clear information on the issues surrounding this aspect of treatment should be readily available to victims, family members, and concerned citizens.
Community quarantining plans should be prepared for use in those events when facility resources are overwhelmed or inappropriate.
3. Directed
therapy, prophylaxis, and vaccines
Treatment
is an evolving issue. Make every effort to keep current information
readily available. Symptom recognition and current recommendations for
agents in CDC’s Category A list can be found in Symptom Recognition and
Therapy Recommendations for CDC Category A Bioagents, at the end of
this portal.
4. Psychological management
Psychological casualty issues are discussed in EMP13, Introduction to
Nuclear, Biological, and Chemical Warfare Portal.
5. Confirmation
of bioagent(s)
Lab
guidelines for selection of specimens, testing, agent identification,
biosafety, transportation, and handling can be found at the CDC’s web
site among other sources.3 The CDC can send a specialized epidemiology
and lab team to sites upon request by state health departments. State,
regional, and federal labs are able to respond to bio attacks.
In addition, a network of laboratories with the ability to analyze potential bio agents is being formed. These labs will be in direct communication with the public health infrastructure.
References
- Kaufman AF et al. The economic impact of a bioterrorist attack: are prevention and postattack intervention programs justifiable? Emerg Infect Dis. 1997;3:83.
- Biological and chemical terrorism: strategic plan for preparedness and response. Recommendations of the CDC Strategic Planning Workgroup. MMWR Recomm Rep. 2000 Apr 21;49(RR-4):1-14. www.bt.cdc.gov
Symptom
Recognition/Therapy Recommendations*—
Category A Bioagents
Obtain up-to-date recommendations in consultation with CDC and/or state local heatlh departments and/or infectious disease experts. Anthrax and smallpox are of particular concern because they are hardy organisms easily grown in large quantities.
| Agent | Symptom Complex | Incubation | Therapy | Immunization | Prophylaxis |
| Smallpox | Prodrome
of fever, headache, nausea/vomiting, malaise; 2-3 days later: macular>deep pustular synchronous face/upper extremity rash. High to moderate lethality. |
7-17 days | Cidofovir undergoing trial | Limited amounts of live virus vaccine at CDC. Smallpox vaccine, 1 dose by scarification | Live vaccine (or vaccina immune globulin) if within 3 days of exposure; > 3 days exposure warrants both. |
| Inhalational anthrax (See other sources for skin and GI forms). |
Influenza-like
illness but with
no sore throat or rhinorhea plus
shortness of breath. Very high lethality |
Usually
1-6 days but can be up to 8 weeks |
STAT IV multidrugs: Cipro or doxycycline plus one of: rifampin, vancomycin, penicillin, ampicillin, imipenem, clindamycin, clarithromycin, chloramphenicol | Bioport
military vaccine: multiple doses and annual boosters |
Confirmed
exposure: 60 days of either Cipro 500 mg every 12 hours or doxycycline 100 mg every 12 hours |
| Plague | Fever, dyspnea, hemoptysis, followed by fulminant pneumonia and respiratory failure. High lethality without treatment | 2-3 days | IV
drugs: streptomycin or gentamycin or doxycycline, or chloramphenicol |
Greer activated vaccine: multiple doses and boosters | Doxycycline
100 mg twice daily or Cipro 500 mg twice daily or tetracycline 500 mg four times daily: 7 days or duration of exposure |
| Botulism | Bulbar
palsies followed by descending symmetrical flaccid paralysis. High lethality without respiratory support (long term) |
1-5 days | DOD
heptavalent antitoxin. CDC trivalent antitoxin. Antibiotics not effective |
DOD
(IND) pentavalent toxoid |
NA |
| Tularemia | Flu-like
illness followed by pulmonary infection and/or sepsis. Mod lethality
without treatment |
1-21 days | 10-14
day course of IM streptomycin or IV/IM gentamycin or IV Cipro |
IND-live
attenuated vaccine>incomplete protection |
Doxycycline
100 mg twice daily or Cipro 500 mg twice daily x 2 weeks |
| Viral
hemorrhagic fevers |
High fever, HA, pains, followed by GI/mucous membrane bleeding. High lethality | 4-21 days | Ribavirin
IV may help some arenaviruses; passive antibody for AHF, BHF, Lassa, and CCHF |
Several
IND vaccines |
Post
exposure oral ribavirin may be effective. |
| AHF-Argentine hemorrhagic fever; BHF-Bolivian hemorrhage fever; CCHF-Crimean Congo hemorrhagic fever; DOD-Department of Defense; GI-gastrointestinal; HA-headache; IND-Investational New Drug; *Sources: CDC (2002)/National Center for Infectious Diseases (NCID). See Vol III EMP16. | |||||