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5
Recognizing Covert Exposure in a Population
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Most of the previous
chapter assumes a scenario much like the explosives-based incidents that
have been typical of terrorism to date--a sudden and highly localized
event producing casualties almost immediately. This is a reasonable
assumption for incidents involving most chemical agents, but it not
likely to be accurate in the case of sulfur mustard, whose effects may
not be obvious for several hours, and nearly all of the biological
agents, whose effects are almost always delayed. This chapter will
therefore focus on what we have previously termed scenario two, a covert
attack with an agent producing signs and symptoms in those exposed only
after an incubation period of several hours, days, or weeks, when the
victims might be widely dispersed.
In these circumstances,
effective medical response to many covert terrorist actions will be
critically dependent not upon Hazmat teams, emergency medical
technicians, and other "first responders," but upon the ability of
individual clinicians, who may be widely scattered around a large
metropolitan area, to identify, accurately diagnose, and effectively
treat an uncommon disease. Education about the threat posed by
bioterrorism, and about the diagnosis and treatment of possible agents
deserves high priority, but the agents most frequently considered
threats are rarely seen in U.S. cities and are therefore likely to
remain quite far down any differential diagnosis. The identification of
a single outbreak or a series of unusual disease presentations or deaths
by the local or state public health department may therefore be the
first clue that a cluster of disease may be related to the intentional
release of a biological agent, unless the perpetrators reveal
themselves. An analysis of the distribution and number of reported cases
will provide important clues regarding the source of infection and can
be used both to guide law enforcement and to help all physicians in the
community make a rapid and accurate diagnosis of new cases and begin
optimal treatment without delay. A very large and efficient attack may
truncate the dispersion of cases in space and time (even in this case,
victims will not be affected immediately, as they would be with chemical
agents), making effective intervention difficult even as it makes it
more obvious that the cause is a deliberate release. Rapid and accurate
epidemiologic investigation will nevertheless be a key factor in
minimizing suffering and loss of life in bioterrorist incidents.
Surveillance systems for collecting reports of such cases and
appropriately trained staff to monitor for disease outbreaks are the
foundation of public health epidemiology. Yet over the last few decades
there has been severe erosion in the capacity of public health
departments to conduct disease surveillance and epidemiologic
investigation.
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SURVEILLANCE AND
INVESTIGATION OF BIOLOGICAL AGENTS |
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A rapid evaluation by
public health epidemiologists is absolutely critical. Delays in
determining the scope and magnitude of the exposure may result in
illness and deaths that might have been avoided if a rapid response,
based on accurate and timely surveillance data, was made.
Surveillance systems
can be passive or active. The large majority of surveillance systems in
place at local, state, and federal levels is passive. These rely on
systems of disease reporting from health providers and are notorious for
their poor sensitivity, lack of timeliness, and minimal coverage. They
are inexpensive to implement, but the quality of information is greatly
limited, and most are not well suited to the needs of modern disease
surveillance, including that needed in the case of a biologic terrorist
event. The single exception appears to be electronic laboratory
reporting (described below), which can give useful and timely data for
epidemiologic purposes.
The Centers for Disease
Control and Prevention (CDC) oversees a large number of passive
infectious disease surveillance systems. These systems are based on
voluntary collaboration with state and local health departments, which
in turn depend on physician-initiated reports of specific diseases or
information from state health laboratories regarding bacterial or viral
isolates. The best known system is the National Notifiable Disease
Surveillance System, which the CDC describes as the backbone of
collaborative reporting procedures involving clinicians, state, and
local health departments, and the CDC. Clinicians, hospitals, and
laboratories in each of the 50 states, the District of Columbia, and the
territories are required (by their own laws) to report cases involving
any of a list of approximately 50 diseases. The list is compiled and
periodically revised by a collaboration of state and CDC epidemiologists
(federal agencies cannot legally dictate to states which diseases should
be reported). It currently includes several of the diseases this report
focuses on as possible bioterrorism agents: anthrax, botulism,
brucellosis, plague, and eastern and western equine encephalitis.
Each state and
territory has its own list of reportable conditions, most of which
overlap with the national list. Certain other medical conditions likely
to be caused by bioterrorists may be reportable conditions in selected
states, but this is not consistently true across the nation.
The reliability of
passive surveillance systems is often quite low, especially if a
physician or hospital fails to make the initial report or does not do so
in a timely manner. While many states may have legal penalties that can
be brought to bear against a provider who does not report, such
penalties are almost never imposed. Neither are there any real
incentives to report. In the case of an illness due to an exotic
biological agent, reporting to proper public health authorities may be
more likely to occur than with an illness caused by a common pathogen.
If a terrorist uses a common pathogen, it may be difficult to determine
the mode of transmission, considering the normal background disease
incidence.
Little or no federal
funding is provided to state and local health departments to support the
surveillance of general communicable diseases. The ability of the states
to support infectious disease surveillance has declined in recent years.
A 1993 survey indicated that 12 states had no professional position
dedicated to surveillance of foodborne and waterborne diseases
(Osterholm et al., 1996). Although most states do have some infectious
disease surveillance capacity, it is most often supported by categorical
(i.e., disease-specific) funds, for example, Acquired Immune Deficiency
Syndrome, vaccine-preventable diseases, sexually transmitted diseases.
These funds generally cannot be used to support noncategorical
communicable disease activities.
CDC has begun an
Emerging Infections Program (EIP), under which grants are awarded to
state or local health departments for improving epidemiological and
laboratory capability. One of the basic benefits the EIP provides for
state-based communicable disease surveillance is more trained
professionals to follow through with investigations that might not have
been initiated because of limited resources. This is one effort designed
to ensure there are enough trained public health epidemiologists to
maintain a working surveillance system, follow up on cases obtained from
that system, and conduct the necessary investigation to develop evidence
for causation.
In seven states
supported by EIP, active population-based surveillance for selected
diseases (foodborne diseases, opportunistic infections in inner-city HIV
patients, community-acquired pneumonias, febrile and diarrheal illnesses
in migrant farm workers, and unexplained deaths in young adults) is
under way. Expansion of these or similar efforts to all fifty states, if
accompanied by an aggressive telecommunications effort to make the
resulting data widely and easily available, would be a good start
towards remedying the domestic surveillance shortfalls identified by a
previous IOM report (Lederberg et al., 1992). Although certainly not
adequate in itself, this remedy could serve as the model for improving
the eroded public health surveillance and investigation infrastructure
necessary for preparing the country to adequately respond to a
biological agent release.
Active surveillance,
which requires staff to actively search for and identify new cases,
provides more timely and accurate information than the commonly used
passive systems. To conduct active surveillance, state and local health
departments must have sufficient numbers of adequately trained
epidemiologists. These scientists collect, compile, analyze, and
interpret the epidemiologic data to determine the source of the
infectious agent. Additionally, capacity is required to conduct the
field investigations that are dictated by the surveillance data or by
case reports.
A national effort to
improve active reporting is the expansion of the Sentinel Surveillance
Networks, supported by the EIP program. In this effort, selected
reporting relationships are established with medical specialty groups
like the Infectious Disease Society of America, the International
Society of Travel Medicine, and a group of about 100 emergency
departments called the Emerging Infectious Disease Network. These
specialists are likely to treat persons with infectious diseases and are
periodically contacted about any specific or unusual conditions.
Further research into
the potential of electronic disease reporting from (and to) physician's
offices is also warranted. Large medical practices, public health
clinics, and managed care settings often have patient medical records in
electronic form, or other electronic documentation that may identify a
case of a reportable (or potential biological terrorism-related)
illness. It would be helpful to determine how to develop the capacity to
have certain records and information automatically sent to proper health
authorities. The legal authority for release of certain information
already exists in most state health codes and some local health
ordinances. Issues of confidentiality and security must be addressed at
the same time as the technological constraints are tackled. An important
group of professionals that should not be overlooked in such a
surveillance effort is the veterinary medicine community. They are often
familiar with a number of the biological agents (anthrax, plague,
brucellosis, tularemia, and the equine encephalitides are all far more
common in animals than in the U.S. population), and their incidence and
prevalence in local livestock and wildlife.
The CDC is currently
examining the development of an emergency department (ED)-based
surveillance system called Data Elements for Emergency Department
Systems (DEEDS). The DEEDS system is designed to standardize electronic
emergency department reporting across clinical systems of care. The
system could be the core of a reporting process which identifies
diseases of public health importance on a daily basis. Systems such as
this could be strengthened to provide real-time surveillance systems of
communities at risk. Such a system would not only identify established
diagnoses but could also report the actual laboratory request for
certain diagnostic assays. These tests would include those done to look
for unusual diseases with potential for biological terrorism (i.e., a
culture for anthrax). Other systems that track the utilization of
specific antibiotics or vaccines (i.e., botulism) could also serve as an
early warning system.
The DoD Global Emerging
Infections Surveillance and Response system (DoD-GEIS) is designed to
conduct antibiotic resistance surveillance at the six DoD tropical
medical research units and coordinate emerging infections surveillance
for the three services. The U.S. Air Force Global Surveillance Program
is an attempt to integrate several surveillance efforts in a way that
tracks emerging diseases. Systems such as this could be utilized to
track diseases of concern for biological terrorism.
Internationally,
projects such as the Canadian Bacterial Disease Network (CBDN) link
university and government laboratories in an effort to track diseases of
importance. Health Canada, Canada's federal health department, is
developing a system to scan the Internet for evidence of new disease
outbreaks, utilizing a new search engine technology designed to
constantly search a large number of predesignated sites, popular as well
as scientific. The system, called the Global Public Health Intelligence
Network (GPHIN), will identify disease reports and link them to the
World Health Organization's information system.
Numerous other
surveillance systems track disease transmission and antimicrobial
resistance both nationally and internationally (Appendix B), but there are few meaningful links
among them. Mechanisms to integrate and link these systems should be
developed.
Detecting and
characterizing an outbreak caused by a covert release of a biological
agent can be difficult, or it may be startlingly obvious. A reported
case of anthrax in an area of the country where anthrax is never
reported or in an individual with no obvious risk factors for the
disease would raise the suspicions of the public health epidemiologist.
Although intentional infection would not necessarily be the first
explanation investigated, a process of elimination or additional case
reports would eventually lead to serious consideration of this
possibility. The time it takes to reach this point is the rate-limiting
step in societal response. It is, then, a critical infrastructure
resource and expertise problem of national importance. Without a
sufficient number of adequately trained epidemiologists at the local and
state level, there may be significant delays in identification and
response. In the case of a biological event, lost time may quickly
translate into lost lives.
Formal training of
epidemiologists occurs in schools of public health, medical and
veterinary schools, and in on-the-job-training in health departments
around the nation. The number of epidemiologists who are prepared for
field public health work is limited. The applied public health sector
competes poorly with academia and industry for new epidemiology
graduates. In addition to those trained at medical schools and schools
of public health, the CDC trains a cadre of Epidemic Intelligence
Service officers (EIS), who are available to assist state and local
epidemiological response. The EIS was created during the Korean War in
response to fears about biological weapons and the perception that state
and local public health resources were inadequate to deal with disease
outbreaks (Langmuir and Andrews, 1952). Now, nearly 50 years later,
facing a threat from these same weapons in the form of biological
terrorism, our nation still finds itself understaffed and underprepared.
Current public health
epidemiology staff often lack access to authoritative guidelines and
other information regarding treatment and control measures. In medium to
small jurisdictions, the person serving as the epidemiologist may have
little formal training in the concepts and methods of field epidemiology
and surveillance and have no background in biological or chemical
threats. Most large states and cities employ trained epidemiologists,
but few of those individuals have any sophisticated knowledge about
biological or chemical weapons. There are national experts who have a
significant amount of knowledge regarding biological agents and the
consequences of their release, but there is little interaction between
these experts and the front-line health department epidemiologists.
No hard data exist on
the current knowledge of state and local health departments regarding
chemical and biological terrorism. From that information, specific
educational and training efforts could be developed and implemented for
all state and local health departments. These solutions might include
the development of training meetings, Internet-based training, video
conferences, or other information exchange technology aimed at the
education of local and state health department staff. Syllabi might
include not only the medical perspectives of the diseases of interest,
but also information regarding modes of transmission, laboratory
considerations, working with emergency responders, educating physicians
and other health care providers about these conditions and reporting
them to the proper health agency, psychological aspects, and the special
considerations of intentional release of these agents. Additionally,
since health departments will be requested to disseminate information
about the agents, the circumstances of the release, and control
measures, information packages for public use will need to be developed.
The Centers for Disease Control and Prevention and national
organizations, such as the Council of State and Territorial
Epidemiologists (CSTE), the National Association of County and City
Health Officials (NACCHO), and others may be well suited to develop and
facilitate this training.
In the last decade,
advances in information technology have greatly accelerated the speed at
which business and commercial transactions and information exchange
occurs. However, these advances have, in large part, not reached local,
and in some cases, state health agencies. The capacity of state and
local health departments to communicate electronically with each other
is severely limited. Fewer than 50 percent of local health departments
have any capacity for Internet connectivity (electronic mail) (National
Association of County and City Health Officials, 1997).
One current system of
communicating news and information about worldwide emerging diseases
utilizes the Internet and electronic mail capabilities. A project of the
Federation of American Scientists, ProMED (Program for Monitoring
Emerging Diseases) was established to provide communication among
sentinel stations around the world capable of detecting unusual
outbreaks of infectious diseases or toxic exposures, including those
that might result from a biological attack. Scientists from around the
world, including many national and global infectious disease experts,
participate in a daily exchange of information regarding infectious
disease cases and outbreaks. Currently there are more than 10,000
participants in this communication system, which provides a forum for
discussing disease occurrence. While ProMED may not be directly useful
in emergency notification of authorities of an unusual, potential
biological agent release, it could serve to quickly bring experienced
scientists together electronically for discussion of the situation. This
would improve the response capabilities of public health departments.
Additional research into the use of ProMED or other Internet-based
information sources (e.g., Outbreak, and Communicable Disease Prevention
and Control) appears warranted.
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LABORATORY CAPACITY
AND SURVEILLANCE |
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The variable and often
substantial delay between exposure to a biological agent and the onset
of clinical signs and symptoms, as well as the possibility of
person-to-person transmission, makes rapid and accurate diagnosis
important, even if treatment of the earliest patients cannot be guided
by laboratory findings. Protection of healthcare workers and treatment
of delayed victims of the attack and secondary victims infected by
contact with an early victim will be much enhanced if exposure can be
confirmed and treatment started prior to symptom onset.
In each case of
suspected exposure, appropriate diagnostic samples from blood, serum,
stool, saliva, or urine are needed for laboratory identification of the
specific agent. Franz et al. (1997) list the following diagnostic
assays: (1) Gram's stain for anthrax and plague; (2) serology, including
enzyme-linked immunosorbent assay (ELISA), agglutination,
immunofluorescent assay (IFA), hemagglutination inhibition, and antibody
(AB) ELISA for anthrax, plague, Q fever, tularemia, viral encephalitis,
viral hemorrhagic fevers, botulinum toxin, and staphylococcal
enterotoxin B; (3) culturing for brucellosis, plague, and tularemia; (4)
Wright-Giemsa stain for plague; (5) virus isolation for smallpox, viral
encephalitis, and viral hemorrhagic fevers; (6) electron microscopy for
viral hemorrhagic fevers; and (7) polymerase chain reaction (PCR) for
identifying the genetic material of smallpox and hemorrhagic fever
viruses. These assays may take anywhere from 2 hours to 30 days to
complete, and, in the case of smallpox and the hemorrhagic fevers,
demand Biosafety Level 4 procedures (e.g., controlled-access laboratory,
change to laboratory coveralls and shower on exit, work conducted in
fully enclosed, separately ventilated biological safety cabinet [CDC and
the National Institutes of Health, 1993]). Even research facilities with
this level of protection are not common.
Although many hospitals
and commercial laboratories have the necessary equipment and expertise
to perform these and similar assays, these diseases are extremely rare
in the United States, and so these laboratories rarely perform these
assays. Most laboratories will thus not be prepared to immediately
conduct the specific analytical test needed to identify the agent, even
when the attending physician is astute enough to ask for the test.
Veterinary diagnostic laboratories may be more likely sources for a
rapid confirmatory assay, since many of the biological agents are
significant sources of disease in domestic animals (nonhuman species may
even be the first victims of a biological attack, unintentionally or as
part of a effort to avoid discovery). Veterinarians and veterinary
laboratory workers, moreover, are likely to have been vaccinated against
many zoonotic diseases, and used to working with these agents. In no
case, however, will a test be done unless a suspicious physician
requests it. A more likely scenario is a round of tests for more common
pathogens, followed by or concurrent with some symptom-based treatment.
Continuing deterioration of the patient's condition or an unusually
large number of affected patients may then lead to involvement of a
state health department laboratory and state epidemiologist.
Although the
capabilities of these laboratories vary widely among the states, all
have working relationships with the CDC and can call upon CDC and other
federal and university laboratories for help. Because these organisms
and diseases are seldom seen in the United States, there are few experts
in these diseases even at the CDC (additional evidence of resource
erosion), and the CDC may need to call upon USAMRIID if one of these
diseases is suspected. Although this channeling of samples from the
initial round of victims to a single expert organization will help in
identifying an outbreak, ensure that medical and laboratory personnel
are protected, and facilitate rapid diagnosis of those delayed or
secondarily infected patients, the process by its very nature is quite
slow and will provide very limited benefit to the first victims.
Research into the utility of developing a network of regional
laboratories (including veterinary laboratories) capable of rapid
diagnostic testing may be useful. Ideally, such a network would involve
strengthening diagnostic expertise and laboratory capability at all
major medical centers, but given the expected frequency of cases
involving biological warfare agents, a more realistic goal might be a
regional approach based on state and local public health laboratories.
Knowledge regarding the
laboratory recovery of a pathogen or positive diagnostic assay is a key
element that public health epidemiologists will need in their
investigation. While, in general, an epidemiologic investigation can be
initiated without laboratory confirmation, final confirmation of the
exact nature of the pathogen will be needed. In some cases, the
laboratory report may serve as the initial notification that there is a
human illness associated with a microorganism that is known to be a
potential terrorist agent. Such a report does not make a diagnosis, nor
does it suggest how the pathogen was acquired by the patient. However,
it could serve as an early notification system for public health,
thereby improving the chances of responding quickly to additional cases
and saving lives.
Currently, biological
samples are taken from the patient and delivered to the laboratory for
analysis. After identification through culture or diagnostic assay, the
results are sent back to the treating facility for use in medical
management of the patient. Most communicable disease surveillance
systems rely on telephonic or weekly written reports for subsequent
transmission of this information to local or state health officials.
Even if a suspect atypical pathogen is identified and interested health
care staff make special efforts to report, the time lag before the
health department knows of the culture may exceed 3 days.
In most large
laboratories, tracking of specimens and results is done electronically
via computer. Recent efforts, spearheaded by the National Center for
Infectious Diseases, at the CDC, and the CSTE have focused on the
possibility of electronic reporting of laboratory results. This
beginning effort has demonstrated that many large laboratories are
capable of downloading assay findings in formats that are usable by
state health officials. Originally designed to reduce the workload of
reporting results to over 50 jurisdictions, electronic laboratory
reporting may serve as an important step towards getting important
information into the hands of the epidemiologist quickly. Additional
research towards full development, and then national implementation of
electronic laboratory reporting will improve the public health response
to a biological release. These solutions will also strengthen the
national disease surveillance infrastructure in general, a glaring need
detailed in the IOM report Emerging Infections: Microbial Threats to
Health (Lederberg et al., 1992).
An important new
laboratory development is the ability to sequence different parts of
microbial genomes. By identifying distinct features of different genes,
it is possible to identify not only microbes of interest but specific
strains and thus more precisely track infectious disease outbreaks. This
"fingerprinting" technique will be useful as a sentinel indicator that a
new strain has entered a community and in distinguishing natural from
intentional releases by identifying microbial or viral strains foreign
to the normal community flora or by matching new outbreak pathogens with
pathogen strains from suspect terrorist groups or intelligence sources.
Such a library of genetic fingerprints would also have enormous value
not only in the effort to track ongoing outbreaks, but also in
predicting antigenic shifts for vaccine production..
The beginnings of a
national network of state health laboratories utilizing this type of
fingerprint technology and sharing fingerprint libraries is under way.
Known as PulseNet, this system, officially initiated in 1998, links the
CDC, U.S. Department of Agriculture, and the U.S. Food and Drug
Administration to a network of state laboratories using pulsed-field gel
electrophoresis to look for characteristic DNA patterns of organisms
implicated in foodborne infections The system is currently capable of
identifying patterns of E. coli 0157:H7 and tracking them across
12 states. Expansion of this system to other states and additional
pathogens is planned and could form the backbone of the national network
suggested above. Including more states is relatively straightforward;
including more pathogens is far more involved, and probably depends not
only on identification of stable and accessible DNA and RNA sequences
that are unique to particular pathogens or classes of pathogens, but
also on simpler, faster, user-friendly microbiological assays. Chapter 6 will address the possibilities of such
improvements and their application to both patient diagnostics and
environmental monitoring and testing.
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CHEMICAL/TOXIN
SURVEILLANCE |
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Although the rapid
onset of symptoms in a large number of victims may make it obvious when
a chemical attack has taken place, poison control centers (PCC) can
serve as the basis for a surveillance system for recognizing covert or
multiple-site poisonings with chemical agents or biological toxins. The
PCC is also the logical place to turn in that scenario for advice on
treatment.
There are no studies
defining the theoretical or actual skills of poison information
specialists and physician staff with regard to chemical or biological
warfare agents, but these individuals are well prepared to provide
advice to emergency personnel in the field and at hospitals on the basis
of signs and symptoms. The PCC may also serve as a coordination point,
even when the "incident" is confined to a narrowly circumscribed locale,
for victims may be dispersed to a number of different medical
facilities. The Tokyo incident involved release of sarin in five trains
on three different subway lines; 278 medical facilities received
patients in the following 48 hours (Sidell, 1996). The value of a
medical information coordinating center in such a situation cannot be
overestimated. Unfortunately, poison control centers have also faced
years of declining resources, with many centers performing few of the
essential tasks to recognize, much less contain, a developing epidemic.
This trend must be stopped or the nation may face a shortage of medical
toxicology specialists who can provide critical treatment information to
treating physicians. Additionally, linkages to the public health system
do not exist in many states and should be encouraged.
At the national level,
the Agency for Toxic Substances and Disease Registry (ATSDR), instituted
a hazardous substances emergency events surveillance (HSEES) system in
1990 (U.S. Department of Health and Human Services, 1993, 1994b, 1995a).
State health departments in selected states collect and transmit
information on the circumstance and health outcomes surrounding
hazardous materials releases. The information is generally provided well
after the event. The information in HSEES is made publicly available for
use in locating, training, and equipping Hazmat teams, first responders,
and employees as well as guiding follow-up epidemiology. However, the
time constraints associated with an incident of chemical terrorism will
not permit a significant real-time surveillance role for the HSEES.
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AIDS FOR CLINICAL
DIAGNOSIS BASED ON SIGNS AND SYMPTOMS |
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Emergency medical
personnel, both at the scene of a hazardous materials incident and at
hospital emergency departments, have a wide selection of reference
materials to call upon for guidance in patient management. These include
traditional textbooks, handbooks such as the three-volume set of medical
management guidelines prepared by the Agency for Toxic Substances and
Disease Registry (U.S. Department of Health and Human Services, 1994a),
paper, CD-ROM (Poisindex, Drugdex, Emergindex), or on-line Material
Safety Data Sheets. Some of these sources provide information on nerve
and mustard agents, but most of these resources are organized by
chemical rather than by symptom complex. That is, given some independent
knowledge of the identity of the hazardous substance, one can readily
ascertain the likely effects and appropriate treatment. Deducing the
substance from the effects is far more difficult. Poison control centers
are routinely faced with this problem and are a good source of help.
The Washington, D.C.
MMST has addressed this difficulty by incorporating a symptom checklist
tool called the "NBC Indicator Matrix" into their training (Defense
Protective Service, 1996). First developed by the Defense Protective
Service, which provides security at the Pentagon, it is a
paper-and-pencil checklist of symptoms. A system for scoring and
processing the results leads to a suggested agent or agents. For Hazmat
incidents at the Pentagon, and by definition, for incidents which lead
to a request for help from the MMST, first responders are highly likely
to turn to such a tool. At other locales, they may need some reason to
suspect terrorism to consider using the matrix. The matrix may have some
utility even in its present form, especially in cases in which exposures
are mild. Difficulties seem likely when victims are critically ill or
have pre-existing illnesses, or in incidents involving more than a
single agent.
With the exception of
some of the toxins (botulinum, SEB, T-2 mycotoxin), and possibly the
hemorrhagic fevers, the initial signs and symptoms produced by the
biological agents considered here are nonspecific--fever, chills,
fatigue, headache, muscle or joint pain, a cough or chest pain. Blood in
the excreta or petechiae (pinpoint-sized, hemorrhagic spots in the skin)
may lead an astute clinician to consider a hemorrhagic fever, but few
U.S. practitioners are likely to recognize the other diseases associated
with biological weapons on the basis of signs and symptoms alone.
Correct diagnosis will almost certainly depend on perception of an
unusual epidemiologic picture by public health epidemiologists. This is
an area where pre-incident intelligence could have a major impact in
reducing the number of casualties.
The development of
interactive computer-based diagnostic systems that enhance the potential
for early recognition and analysis of the unique aspects of rare
diseases, including the manifestations of disorders produced by
biological and chemical agents, would be a substantial advancement. An
integrated system that utilizes natural disease rates and clinical
probabilities, based upon signs and symptoms, and laboratory findings
could enhance an early warning system prior to a clinician's decision on
a particular diagnosis or disease. One model, the Global Infectious
Disease and Epidemiology Network (GIDEON), uses a Bayesian matrix for
compatible diagnoses. This particular system, which focuses on unusual
diseases, is limited by the weight it places on country of disease
origin and requires a database that might not be initially available.
An improved system with
refinements in diagnostic decisionmaking that offers the untrained or
inexperienced clinician assistance in considering a chemical or
biological exposure would be of great value. For any system this would
necessitate a complex, multiple search mechanism that includes early
signs and symptoms of atypical disorders caused by biological or
chemical terrorists agents.
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The committee
recognizes that the first of the following recommendations is a
recommendation, not for research itself, but for the prerequisites for
productive R&D. The committee strongly believes that no research
effort, no matter how important or sophisticated, will be productive
until the nation rebuilds the public health infrastructure to a level at
which the results of appropriate research can be properly applied. This
infrastructure improvement would have enormous value to the average
citizen on a day-to-day basis and would generate significant health
benefits beyond readiness for terrorist events.
5-1 Immediately undertake improvements in CDC, state,
and local disease and exposure surveillance and epidemiologic
investigation infrastructure, and support them on a long-term basis.
These improvements must focus on communicable disease epidemiology and
laboratory programs and on poison control centers.
5-2 Evaluate the current educational/training needs of
state and local health departments regarding all aspects of a biological
or chemical terrorist incident. Develop and put in place programs and
materials based on the research findings and aimed at preparing these
departments and their health care partners to adequately identify and
respond to such an incident.
5-3 Conduct research on new, faster, and more complete
methods of electronic disease reporting to enhance surveillance at all
levels, including the health care provider, local, state, national, and
global surveillance levels. Such research should include evaluating the
benefits of utilizing Internet and electronic mail technologies to
improve reporting and access to expertise concerning biological or
chemical weapons before, and during a release.
5-4 Enhance research efforts to develop nucleic acid
fingerprinting techniques capable of tracking microbes likely to be used
by terrorists. A library of these fingerprints, and the laboratory
techniques to develop and use them should be available to a network of
cooperating regional laboratories.
5-5 Conduct research into the development of
symptom-based, automated decision aids that would assist clinicians in
the early consideration and identification of unusual diseases related
to biological and chemical terrorism.
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