The Critical Role of Clinicians in Bioterrorism Response

For clinicians, responding to a bioterrorism attack is similar in many ways to responding to naturally occurring communicable disease outbreaks. Both situations typically require early identification of ill or exposed persons, rapid implementation of preventive therapy, special infection control considerations and collaboration or communication with the public health system. The first indication of an unannounced biologic attack will likely be an increase in the number of persons seeking care from primary care physicians.

In 2001, alert clinicians initiated the public health response to the anthrax attacks by recognizing an unusual clinical syndrome, ordering appropriate laboratory tests and notifying public health officials. Primary care physicians and specialists alike must be familiar with specific clinical syndromes and treatments associated with agents of bioterrorism. They should also know the best ways to rapidly notify public health authorities. In addition to identifying cases and treating ill patients, clinicians play a critical role in managing post-exposure prophylaxis and its complications.

Psychological and mental health problems brought on by the event must also be identified and addressed. Clinicians are faced with the challenge of differentiating between the worried well and people who have actually been exposed to or infected by an agent. Some ill people may behave with signs and symptoms similar to those of the outbreak disease, yet may not have been exposed.

The clinician must have knowledge of the modes of transmission, incubation periods and communicable periods of these diseases. The clinician must also be skilled in conducting clinical evaluations and eliciting thorough histories that include relevant occupational, social, and travel information. The epidemiologic setting of cases plays a critical role in guiding diagnostic tests and treatment. The primary care clinician also has the best opportunity to obtain relevant information, particularly if the patient’s condition deteriorates. Clinicians should also have a working knowledge of the basic classes of isolation and infection control measures recommended for patients exposed to the various agents of potential bioterrorism.

CDC Classification Categories of Potential Biological Agents:
The CDC divides potential biological agents according to the following categories. 


Biological Agent


A (highest immediate risk) Variola major
Bacillus anthracis
Yersinia pestis
Clostridium botulinum (botulinum toxins)
Francisella tularensis
Filoviruses and arenaviruses (e.g., Ebola virus, Lassa virus)
Viral hemorrhagic fevers
B (next highest risk) Coxiella burnetii
Brucella species
Burkholderia mallei
Burkholderia pseudomallei
Alphaviruses (VEE, EEE, WEE)*
Rickettsia prowazekii
Toxins (e.g., ricin, staphylococcal enterotoxin B)
Chlamydia psittaci
Food-safety threats (e.g.,Salmonella species, E. coli0157:H7)
Water-safety threats (e.g., Vibrio choleraeCryptosporidium parvum)
Q fever
Typhus fever
Toxic syndromes
C (potential, but not immediate, risk) Emerging-threat agents (e.g., Nipah virus, hantavirus)  

VEE – Venezuelan equine encephalitis   EEE – eastern equine encephalitis   WEE – western equine encephalitis

Category A agents are thought to pose the highest immediate risk for use as biologic weapons. They include agents that have been used as biological weapons before, are relatively easy to produce and/or have high mortality profiles.

Category B agents have the next highest risk. They include agents that have caused naturally occurring outbreaks and food and water borne agents.

Category C agents are thought to pose a potential, through not immediate risk for use as biologic weapons. They are agents that are thought to have been experimented with for bioterrorism use and could still be developed into biological agents. Another reason for inclusion on this list is the understanding that these agents require special action for public health preparedness.

Agents that are thought to make “effective weapons of mass destruction” include those that are

  1. easily disseminated or transmitted from person to person,
  2. relatively easy and inexpensive to produce,
  3. produce high mortality or widespread infection, and
  4. may result in panic and social disruption.

When You Hear Hoof Beats, Don’t Overlook the Possibility of Zebras Approaching

As in naturally occurring outbreaks, early recognition of a bioterrorist attack is critical for rapid implementation of preventive measures and treatment. Early recognition can be challenging because after exposure to a biologic agent a patient may initially present with non-specific signs and symptoms such as malaise, fever and weakness.

Maintaining a heightened level of suspicion, including watching for epidemiologic clues, should help physicians recognize intentional exposure to these agents. Epidemiologic clues to intentional events include the following:

  1. The presence of an unusually large epidemic or one case of a very rare disease or smallpox. While one case of plague of Tularemia might be a natural occurrence, four cases in the same hospital should be a red flag.
  2. Unusually severe disease or unusual routes of exposure. Diseases that are weaponized and delivered in high doses can present in dramatic fashion.
  3. Unusual geographic area, unusual season or absence of normal vector
  4. Multiple simultaneous epidemics of different diseases
  5. Outbreaks of unusual zoonotic diseases in local animals
  6. Unusual strains of organisms or antimicrobial-resistance patterns
  7. Higher attack rates than expected in persons with common exposures
  8. Credible threat, as determined by authorities, of biologic attack
  9. Direct evidence of biologic attack

The identification of a bioterrorist attack requires clinicians to be prepared, alert and open-minded. Familiarity with the clinical features of diseases from potential bioterrorist agents will allow recognition of potentially significant differences from naturally occurring cases. The anthrax attack of 2001 demonstrated that the clinical illness associated with a deliberately released agent might differ from typical natural infections.

Contact the Department of Health!

Once a potential outbreak or significant cluster or event has been identified, prompt consultation with public health authorities is critical. The Department of Health can be contacted 24 hours a day for consultation or reporting on a suspicious illness.

The Department’s Communicable Diseases Program can be contacted during normal business hours at 410-222-7256.

After hours, physicians may contact the Department of Health Physician-on-Call at 443-481-3140.

The CDC also maintains a 24 hour Emergency Response Hotline at 770-488-7100.

The Medical Community: Part of the Federal, State and Local Response to Terrorism

As part of the overall National Response Plan, public health and the medical community have primary responsibility to prepare for and respond to biological events. This responsibility is included under emergency support function (ESF) number 8 in the NRP. Each hospital is now required to maintain a current Emergency Operations Plan that details how that institution will operate in emergency situations. We encourage all county physicians to locate and read their institution’s EOP.

Public health agencies have new responsibilities as a result of ESF 8. Surveillance and disease monitoring in the community have taken on increased significance and have become more sophisticated. The county’s surveillance input is included in State and Federal databases designed to detect changes over baseline in the health of communities. In addition to data from local health departments, national “syndromic surveillance” projects collect data on hospital emergency department visits with certain disease descriptors “syndromes,” such as respiratory illness with fever, gastrointestinal syndromes and others. It is hoped that awareness of an increase in respiratory illness with fever, for example, could lead to a more rapid discovery of emerging epidemics or terrorist events. In addition to ED data, over-the-counter sales data is being collected to monitor the demand for medications used to treat illnesses such as diarrhea, cold and flu.

Public health is now taking a more active role in the emergency response capabilities maintained in the community and actively seeking to strengthen relationships with community partners in fire, police, response community medical community, and local volunteer organizations. The Department of Health also has its own EOP, which includes plans for the local delivery of Strategic National Stockpile (SNS) resources, risk communications strategies, Red Cross shelter support and crisis mental health intervention.

The SNS, nationally maintained by the CDC, is a repository of antibiotics, vaccines and emergency medical equipment such as ventilators, masks and gloves. Supplies are able to be delivered within 12 hours after the Governor requests them. SNS contents fill seven tractor-trailer trucks. Current plans call for local responders to “go it alone” for the initial 72 hours after an event even if Federal resources will eventually be assigned. Pre-event planning will make the difference in how effective response efforts will be during an actual event.

How Physician’s Link Can Help

The Bioterrorism Section of the Physician’s Link is designed to provide you with rapid access to concise information and resources that will help you prepare for and respond to a bioterrorism event in Anne Arundel County. Each disease or agent section includes a brief clinical overview, patient handout (for patients who might have questions or for use during an event), PowerPoint presentation and links to additional resources.

Anne Arundel County Department of Health | 3 Harry S. Truman Parkway | Annapolis, Maryland 21401 | Phone: 410-222-7095

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