|Bioterrorism: Background and High Priority AgentsPeople have been using bioterrorism to do horrible things to
each other since time began. For several years, many have questioned when the next
bioterrorism event would occur, rather than if it would occur. While that question has
been answered in recent weeks, we do not know how far-reaching the effects might become.
Terrorism is a form of psychological warfare causing fear among the
public, in addition, to casualties. Bioterrorists have achieved that objective nationwide
with plenty of reverberations in Utah. Utah law enforcement officials have deemed more
than 130 incidents as suspicious enough to warrant further investigation and testing from
October 11 through October 31, 2001. In that time, the Utah Department of Health (UDOH)
has not detected B. anthracis spores in any environmental or clinical sample
submitted for testing. Unfortunately, that is not the case on the East Coast as anthrax
cases continue to surface. As of October 31, 2001, four deaths have resulted from
inhalational anthrax, including one Florida resident, one New York resident, and two
Washington D.C. postal workers. Five additional inhalational anthrax cases have been
identified, including another Florida resident, one New Jersey Postal worker, two
additional Washington D.C. postal workers, and one mail handler from the State Department
offsite mailroom. In addition, three cases of cutaneous anthrax have been identified in
both New York and New Jersey. Environmental sampling and testing have revealed anthrax
spore contamination in postal facilities, media organizations, and government buildings
located in Florida, Maryland, New Jersey, New York, Virginia, and Washington D.C.
The proper response to these findings continues to be defined and
clarified while preventative efforts continue to be implemented. While vaccination has
been the single most cost-effective public health intervention in history, it is
impractical to stockpile or administer vaccines sufficient to protect every citizen from
every biological agent. The very high costs and the great difficulties involved in
vaccinating large populations, along with the broad spectrum of potential agents, make it
impossible to use vaccines to protect the general population against bioterrorism. Thus,
vaccines cannot be considered a first line of defense against bioterrorism for the general
population, as they can be for the relatively small military population. What is practical
is a strategy to detect an event as early as possible, respond quickly, and deliver
resources efficiently. Health officials need to maintain a high level of suspicion and
improve surveillance capacity. The foundation of a good disease surveillance system is a
framework of physicians, physician assistants, nurse practitioners, and clinical
laboratorians who will recognize the public health implications of reportable diseases,
disease clusters, unusual illnesses, and who will notify health department officials so
that public health action can be undertaken promptly and efficiently.
The UDOH would like to remind providers to be especially vigilant, not
only for symptoms consistent with anthrax, but also for symptoms consistent with other
potential bioterrorism agents. Although nearly any microbe could be put to criminal use,
the Centers for Disease Control and Prevention has classified six diseases as
Category A, or high priority disease, 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; 4) and
require special action for public health contingency planning. Figure 1 includes Category
A diseases, suspicion of any of which should prompt an immediate call to the local or
state health department.
|Figure 1. Epidemiology and Microbiology
of Category A Bioterrorism Agents
anthracis, a spore-forming Gram-positive rod
anthrax is the most lethal form of anthrax. The incubation period typically ranges
from 1 to 7 days but may last up to 60 days. Initial symptoms include mild fever, muscle
aches, and malaise. Inhalational anthrax has a high case-fatality rate, progressing to
respiratory failure (with radiographic evidence of mediastinal widening) and shock. Cutaneous
anthrax is the most common form of the disease and appears to require lower doses of
spores rubbed into the skin or introduced into cuts in the skin. The incubation period
ranges from 1 to 12 days. A skin lesion evolving from a papule, through a vesicular stage,
to a depressed black eschar, characterizes cutaneous anthrax. The lesion is usually
painless, but patients may also have fever, malaise, headache, and regional
lymphadenopathy. (Note: Recent cutaneous anthrax cases had lesions clinically
identified as Brown Recluse bites). Gastrointestinal anthrax usually
follows after eating raw or undercooked contaminated meat and can have an incubation
period of 1 to 7 days. Symptoms are severe abdominal pain followed by fever and signs of
septicemia. Lower bowel inflammation typically causes nausea, loss of appetite, and fever
followed by abdominal pain, hematemesis, and bloody diarrhea.
produced by the anaerobic Gram-positive rod Clostridium botulinum
||The botulinum toxins
are the most toxic compounds, per weight of agent, known to man, requiring only 0.001
microgram per kilogram of body weight to kill 50 percent of animals studied. Botulism
usually begins with cranial nerve palsies, including ptosis, blurred vision, diplopia, dry
mouth and throat, dysphagia, and dysphonia. This is followed by symmetrical descending
flaccid paralysis, with generalized weakness and progression to respiratory failure.
Symptoms generally begin as early as 12 to 36 hours after inhalation or ingestion of
pestis, a Gram-negative rod
||Clinical features of
pneumonic plague include fever, cough with muco-purulent sputum, hemoptysis, and chest
pain. A chest radiograph will show evidence of bronchopneumonia. The incubation period is
1-7 days. Early administration of antibiotics is critical as pneumonic plague is
invariably fatal if proper therapy is delayed more than one day after the onset of
virus, an orthopoxvirus
||If one inhales a
single particle of smallpox, he or she can come down with the disease from 7-19 days. The
acute clinical symptoms of smallpox closely resemble other acute viral illnesses. In order
for prompt public health intervention to take place, smallpox must be distinguished from
other vesicular exanthems, such as chickenpox, erythema multiforme with bullae, or
allergic contact dermatitis. Smallpox begins with a 2- to 4-day nonspecific prodrome of
fever and myalgias before rash onset. Of particular importance is that clinicians
differentiate varicella (chickenpox) from smallpox. The rash of varicella is most
prominent on the trunk and develops in successive groups of lesions over several days,
resulting in lesions in various stages of development and resolution. In comparison, the
vesicular/pustular rash of smallpox is typically most prominent on the face and
extremities, and lesions develop synchronously. (Note: most people vaccinated for smallpox
have had a waning immunity after 10 years.)
Francisella tularensis, a Gram-negative rod
||Inhalation of only a
few F. tularensis organisms can cause an abrupt onset of an acute, nonspecific
febrile illness beginning 3 to 5 days after exposure, with pleuropneumonitis developing in
a substantial proportion of cases during subsequent days. Pneumonic tularemia is a severe
atypical pneumonia that may be fulminant and with a high case fatality rate if left
Ebola and Marburg, filoviruses
abrupt onset of fever, myalgia, and headache with an onset of 2-19 days following exposure
to body fluid of infected person. Other signs and symptoms include nausea and vomiting,
abdominal pain, diarrhea, chest pain, cough, and pharyngitis. A maculopapular rash,
prominent on the trunk, develops in most patients approximately 5 days after onset of
illness. Bleeding manifestations, such as petechiae, ecchymoses, and hemorrhages, occur as
the disease progresses.
Responding Step by Step
Monday 4:00 a.m.
The pager goes off. A seasoned epidemiologist awakens to find an odd number displayed. The
call is immediately returned to hear the voice of a concerned and anxious first responder.
The responder inquires about how to handle a potential infectious substance and what
protocols to follow. Instruction is given by the epidemiologist and coordination is in
place to ship the sample to the state lab for analysis. Consultation is provided
concerning steps to protect the first responders and others possibly exposed. A call is
made by the epidemiologist to a public health microbiologist who travels to the laboratory
and is awaiting the sample when it arrives. Tests are initiated to discover the identity
of the substance.
Thursday 3:30 p.m., Three Days Later
A call is received from a local hospital notifying public health that they have seen an
unusual increase in patients presenting with clinical symptoms that suggest an infectious
disease outbreak (for example, patients presenting with an unexplained febrile illness
associated with sepsis, pneumonia, adult respiratory distress, and mediastinitis).
Laboratory work is again sent to the state laboratory for testing. A presumptive diagnosis
is made by the physician along with input from public health. Appropriate precautions and
possible treatments are discussed with the physician.
Thursday 5:30 p.m.
A team of epidemiologists are sent to the hospital to begin an epidemiological
investigation to discover the source of exposure and to see if the sample provided by
first responders earlier in the week could be linked to the hospitalized individuals. The
investigators goal is to identify and characterize the cluster of illness and
identify the potential public health impact.
As the epidemiologists complete the initial steps of the investigation,
it appears this could be a bioterrorism event. Public health contacts local law
enforcement and the Federal Bureau of Investigation. Appropriate information is shared
with these agencies and the choice is made to conduct further joint interviews.
A call is made by the state epidemiologist to the Centers for Disease
Control and Prevention (CDC). The CDC sends additional personnel to assist with the
Thursday 6:00 p.m.
The state health department sends notification via the Health Alert Network (HAN) to all
state health departments, other hospitals and various other state agencies notifying them
of the situation and initial investigation results. A message is delivered to recipients
of the states infectious disease list server in attempt to notify and explain what
is being seen.
Presumptive tests are completed by the state lab. Public health recommends appropriate
control measures, treatment and prophylaxis guidelines for what presumptively is a
life-threatening illness. Again, both the HAN and list server send out additional findings
to all recipients.
Public health begins to notify the medical community more extensively
to discuss findings and to coordinate treatment protocols.
The public information officer from the health department issues a
press release to notify the public of these findings and to recommend any needed action to
Friday 3:00 p.m.
Many physicians and hospitals are also reporting numerous cases of related illnesses that
they have seen within the past 24 to 48 hours. Public health contacts local pharmaceutical
distribution centers to request additional supplies of medication.
State public health officials, in consultation with the CDC, request
the National Pharmaceutical Stockpile.
The public information officer and other officials hold a press
conference to update the media and public and recommend actions to be taken.
Public health is distributing pharmaceuticals to potentially exposed individuals and
medical supplies where needed.
Public health and the American Red Cross are coordinating certain areas
of response including prophylaxis centers, psychological treatment personnel and pastoral
services, as well as additional medical response resources and personnel.
Epidemiologists continue gathering case counts/information and related
statistics. Data management, disease tracking, coordination with the medical community,
public education and implementation of control measures are continuing and will continue
throughout the event.
There is a tendency for terrorists to move into new areas of violence when current areas
no longer achieve the intended effect publicity, reaction, chaos. As terrorism
creeps into the biological realm, the greatest payoff in combating it lies in focusing on
how best to respond to an attack. A coordinated effort within organizations and between
public health, emergency responders, the medical community and other response agencies is
needed to effectively and efficiently respond to a bioterrorism event. Public health needs
to continue to plan and acquire resources to respond to such events, while the medical and
emergency service communities need to ensure that they are trained to recognize the
symptoms of diseases associated with bioterrorism agents.
We are today with respect to bioterrorism where we were nearly 30 years
ago with respect to conventional terrorism. A new international threat was
emerging then, but it was unclear as to the direction it would take. It took years to
comprehend the diverse nature of those kinds of events (highjackings, hostage situations,
bombings) and for governments to take actions against them. Biological terrorism does not
give us the luxury to watch events unfold and then determine the proper resources. As
bioterrorism events could have catastrophic effects in terms of lives lost and create a
medical, political, and social crisis unparalleled in our history, it is important to
prepare now for this new age of terrorism.
Join the List Server
If you are interested in joining the Utah Infectious Disease List
Server, please email Jenifer Lloyd at firstname.lastname@example.org.
Facts: Test Your Knowledge
or fiction: More than 95% of anthrax cases are inhalational.
Ninety-five percent of anthrax cases are cutaneous cases. Before October 2001, no case of
inhalational anthrax had been reported in the United States since 1978.
2. Fact or fiction: A nasal swab test is not an approved diagnostic
tool for determining whether or not a person has been exposed to anthrax.
Fact ! At
present, the Centers for Disease Control and Prevention does not recommend the use of
nasal swab testing on a routine basis to determine whether a person has been exposed to B.
anthracis or as a diagnostic tool. At best, a positive result may be interpreted only
to indicate exposure, whereas, a negative result does not exclude the possibility of
exposure. Nasal swabs are discouraged except in situations where a positive powder was
identified. Public health officials may use nasal swab screening to evaluate the
dispersion of spores.
3. Fact or fiction: Household contacts of anthrax cases should be given
Fiction ! Since
anthrax is not transmissible person to person, there is no need to quarantine people
suspected of being exposed to B. anthracis or to treat contacts (e.g., household
contacts, friends, or coworkers) of people ill with anthrax, unless the contacts were also
exposed to the same source of infection.
4. Fact or fiction: Patients reporting flu-like illness should be
tested for anthrax.
Fiction ! There
is very little reason to suspect anthrax unless a patient has had a specific exposure. To
cause infection, B. anthracis spores must enter the skin, be ingested, or inhaled
(infection results from inhalation of 8,000- 40,000 bacterial spores). If anthrax is
suspected, the diagnosis can be confirmed by obtaining the following appropriate
laboratory specimens based on the clinical form of anthrax:
Inhalational: blood, CSF, and/or sputum
Cutaneous: vesicular fluid and/or blood
Gastrointestinal: vomitus, feces, and/or blood
5. Fact or fiction: Anthrax infection is curable if treated early.
Fact ! Although
effectiveness may be limited after symptoms are present, high dose antibiotic treatment
should be undertaken. Supportive therapy may be necessary. The case fatality rate for
inhalational anthrax approaches 100% unless antibiotic treatment is initiated before
disease onset. Prophylactic treatment is very effective if begun promptly following an
exposure. The case fatality rate for cutaneous anthrax is 20% without, and <1% with,
antibiotic treatment. The case-fatality rate for gastrointestinal anthrax is estimated to
be 25 to 60%, and the effect of early antibiotic treatment is not established.
Treatment options: The current B. anthracis strains
associated with the intentional exposures are susceptible to ciprofloxacin and
doxycycline. The current strains are also susceptible to chloramphenicol, clindamycin,
rifampin, vancomycin and clarithromycin, but there are limited or no data on the
effectiveness of using these agents for B. anthracis infections or exposures.
Cephalosporins should not be used for post-exposure prophylaxis or treatment of B.
anthracis infections. Amoxicillin or penicillin VK may be an option for post-exposure
prophylaxis in situations where ciprofloxacin or doxycycline is contraindicated.
Combination therapy with two or more antimicrobials may be appropriate in patients with
To view an interactive tutorial to learn additional anthrax facts
please visit the following webpage: http://www.nlm.nih.gov/medlineplus/tutorials/anthrax.html
Department of Health, Office of Epidemiology
Monthly Morbidity Summary - October 2001 - Provisional Data
Newsletter is published monthly by the Utah Department of Health, Division of Epidemiology
and Laboratory Services, Office of Epidemiology, to disseminate epidemiologic information
to the health care professional and the general public.
Send comments to: The Office of Epidemiology, Box 142104, Salt
Lake City, UT 84114-2104, or call (801) 538-6191
Approval 8000008: Appropriation 3705
Rod Betit, Executive Director, Utah Department of Health
Charles Brokopp, Dr.P.H., Division of Epidemiology and Laboratory Services
Gerrie Dowdle, MSPH, Managing Editor
Connie Dean, Production Assistant