Biological terrorism against animals and humans:
a brief review and primer for action
L. Noah, DVM, MPH, DACVPM; Don L. Noah, DVM; Harvey R. Crowder, DVM, MS,
the Office of the Air Force Surgeon General Headquarters, United States
Air Force, 110 Luke Ave, Ste 400, Bolling Air Force Base, Washington, DC
20330 (Donald L. Noah); 20707 North 110th Ave, Sun City, AZ 85373 (Don
L. Noah); and the Oregon Department of Human Services, 800 NE Oregon St,
Ste 608, Portland, OR 97232 (Crowder). Dr. Donald L. Noah's present address
is 902 Seminole Rd, Frederick, MD 27101.
The recommendations contained in this
article represent the opinions of the authors and do not necessarily reflect
on the official position of the US Government, the Department of Defense,
or the Department of the Air Force. Address correspondence to Dr. Donald
|This article, published in the
July 1, 2002 issue of the Journal of the American Veterinary Medical
Association, is provided here as a public service because of its potential
relevance to bioterrorism. This article is the first of a new series of
articles being prepared under the guidance of the Council on Public Health
and Regulatory Veterinary Medicine for publication in the Journal of
the American Veterinary Medical Association.
AVMA members may access all articles
published in the 2nd edition of the Zoonosis Updates from the Journal
of the American Veterinary Medical Association, published in 1995,
by visiting the NOAH Resource Center. Members and nonmembers may contact
the AVMA to purchase a hard copy version of the monograph.
mid-1990s, there has been a change in the public's perception of the threat
from biological weapons. Fears of intentional biological warfare and terrorism
were heightened by the revelations that Iraq and the Soviet Union developed
extensive biological warfare programs(1) and the Aum Shinrikyo's attempted
uses of anthrax and botulinum toxin and successful use of sarin gas.(2)
Although concern about the intentional use of biological agents is long
standing, actual use is rather limited. In a February 2001 review(3) of
potential bioterrorism events, W. Seth Carus, a National Defense University
researcher, could only identify "...five groups that used or tried to use
biological agents." However, he documented an increased interest in the
criminal and terrorist use of biological agents; at least 54 recent open-source
accounts of terrorist group activities mentioned an interest in biological
Subsequent to that limited history,
the reality of biological weapons has been shockingly underscored by the
recent use of anthrax by unknown criminal groups causing 23 cases of anthrax,
including 5 deaths, in the United States.(4)
Biological Threat Agents Against
With the realization that the threat
of bioterrorism was increasing, the Centers for Disease Control and
Prevention (CDC) has developed a strategic plan for the response to
biological and chemical terrorism.(5) The plan of the CDC outlines
3 categories of biological agents that could or have been used by terrorist
groups. The categories are grouped by priority for preparation as follows:
Category A consists of the highest
priority of agents. These agents pose a risk to national security because
they can easily be disseminated or transmitted person to person, cause
high mortality with potential for major public health impact, might cause
public panic and social disruption, and require special action for public
health preparedness. The category A agents are variola major (smallpox),
anthracis (anthrax), Yersinia pestis (plague), Francisella
tularensis (tularemia), arenaviruses (Lassa fever and Argentine hemorrhagic
fever and related viruses), filoviruses (Ebola hemorrhagic fever and Marburg
hemorrhagic fever), and Clostridium botulinum toxin (botulism).
Category B consists of the second highest
priority of agents because they are moderately easy to disseminate, cause
moderate morbidity and low mortality rates, and require specific enhancements
of diagnostic capacity and surveillance activities. The category B agents
are Coxiella burnetti (Q fever), Brucella spp (brucellosis),
mallei (glanders), alphaviruses (Venezuelan/eastern/western encephalitides),
ricin toxin from Ricinus communis (castor beans), epsilon toxin
of C perfringens, and Staphylococcus enterotoxin B. A subset
of Category B agents includes pathogens that are food or waterborne and
include Salmonella spp, Shigella dysenteriae, Escherichia
coli O157:H7, Vibrio cholerae, and Cryptosporidium parvum.
The category C agents are those that
include emerging pathogens that could be engineered for mass dissemination
in the future because of availability, ease of production and dissemination,
and potential for high morbidity and mortality and major health impact.
The category C agents are Nipah virus, hantaviruses, tickborne hemorrhagic
fever viruses, tickborne encephalitis viruses, yellow fever, and multidrug-resistant
As part of the strategic planning process,
CDC and other federal agencies are providing support to state and local
health departments through a number of grants to improve epidemiologic
surveillance, public health information management and communication infrastructure,
public health laboratory capability, and public health emergency planning.(6)
Throughout the planning documents developed for bioterrorism response,
are considered a key part of the disease surveillance system.(7-10) Additionally,
the Department of Justice and the CDC's Public Health Assessment Instrument
for Public Health Preparedness recommends that local public health planners
develop a roster of individuals with technical expertise able to respond
to a biological, chemical, or radiological terrorist event; plan to initiate
contact with veterinarians and other public health professionals
within an hour; disseminate information on terrorist threats to veterinarians
within 2 hours; develop a roster of veterinary laboratories for specimen
handling and veterinary facilities for handling affected animals; estimate
the numbers of veterinarians who have received 8 or more hours in
emergency preparedness training in the past year; provide training for
on decontamination and contagion hazards that may accompany a biological,
chemical, or radiation incident; include veterinarians in emergency
exercises; and facilitate contact with veterinary researchers.(11)
It is vitally important that all facets
of veterinary medicine stay involved in the preparations to respond to
bioterrorism. This should be obvious by the known or potential zoonotic
nature of many diseases in the CDC bioterrorism categories (anthrax, plague,
tularemia, Ebola, Marburg, Lassa fever, Argentine hemorrhagic fever, Q
fever, brucellosis, glanders, Venezuelan encephalitis, eastern and western
equine encephalitis, salmonellosis, Escherichia coli O157:H7, cryptosporidiosis,
Nipah virus, hantaviruses, tickborne hemorrhagic fever viruses, tickborne
encephalitis viruses, and yellow fever)(12,13) and the recognized potential
for expertise, support, and response that veterinarians provide
in animal care and in the general response to a bioterrorism attack. Veterinarians
have an important role in bioterrorism response preparation, surveillance
for potential bioterrorism events, treatment of the ill, and in the control
Bioterrorism Against Animal Populations
Traditional thinking and planning regarding
bioterrorism has focused primarily on humans as the primary target. If
the perpetrator's objectives can be met solely through the creation of
human illness, death, and the associated panic, this may be true. However,
if economic and political vulnerabilities are factored in as contributing
issues, then agricultural bioterrorism (the intentional targeting of a
nation's livestock and crop resources) becomes more likely, perhaps even
more so than attacks against humans.(14) Further, an attack on the food
supply or food economy of a nation might be more attractive to terrorists
because of the secondary effects on humans and the potential for deniability
that might make the response or retribution less vigorous.(15) A recent
General Accounting Office study(16) concluded that intentional disease
attacks against agricultural commodities, especially livestock, would be
economically devastating and presently are inadequately defended against.
Other factors contributing to the vulnerability of US agriculture are the
continuing trends of intensive production techniques, vertical integration
of the production continuum, the increasing industrial dependence on the
export market, and the lack of US livestock resistance against pathogens
and pests that no longer prevail in the continental United States.
This agricultural vulnerability, coupled
with the relative ease of procuring, producing, and disseminating animal
pathogens, allows potential perpetrators to apply the tenets of asymmetric
tactics to significantly harm a nation that is increasingly immune to conventional
Although the human medical community
recently identified many shortfalls in national bioterrorism defense and
has initiated great improvements toward their remedy, the veterinary and
agricultural communities have lagged behind, especially those portions
involved in food animal production. Amidst this seeming backdrop of impending
doom, however, the US veterinary community is not wholly unprepared. In
fact, a recent study by US public health officials concluded that the veterinary
education model "which looks at populations rather than individual patients,
might serve as a model for the medical community."(17) The following efforts,
individual and collective, are offered as recommendations for improving
our national defense against attacks on our livestock and resultant impacts
on our social and economic viability.
Practitioners—The key prerequisite
for any effective surveillance system is knowledge of the baseline disease
prevalence and incidence rates. Without this information, it is impossible
to tell whether disease occurences are below or above the threshold for
specialized action. Although most veterinary practitioners develop some
sense of these disease rates in their areas, formally tracking them over
time might prove valuable.
Similar to baseline disease rates,
timely knowledge of key production variables will allow early detection
of adverse health events. Farm owners and managers will be the primary
surveillance system operators in this case. However, clear and frequent
lines of communication between the producers and their veterinarians
(the "first responders") will facilitate an early and effective response.
Examples include dairy herd milk production and breeding rates, swine breeding,
farrowing and rate of weight gain figures, poultry egg production, and
respiratory disease rates.
Another prerequisite for responding
to a bioattack against livestock is the ability to recognize the signs
and symptoms of the likely disease agents. Those diseases might include
those no longer prevalent in the United States, against which our livestock
have low immunity, and which would significantly affect our agricultural
economy. Conveniently, the Office International des Epizooties (OIE)
publishes a list of animal diseases that are highly infectious, capable
of rapidly spreading across international borders, becoming widespread,
and have the potential to inflict catastrophic economic losses and social
disruption.(18) This complete OIE list A includes foot and mouth disease
(FMD), vesicular stomatitis, swine vesicular disease, rinderpest, peste
des petits ruminants, contagious bovine pleuropneumonia, lumpy skin disease,
Rift Valley fever, bluetongue, sheep and goat pox, African horse sickness,
African swine fever, classic swine fever, fowl plague, and Newcastle disease.
Fortunately, many of these diseases have not been prevalent in the United
States for many years, but that may make their timely recognition problematic.
To prevent confusion and costly delays in recognition and reporting,
should seek continuing education opportunities on natural and intentionally
introduced foreign animal diseases.(19-22) This education effort should
include a review of the clinical signs of these diseases, as well as variations
in their relative species susceptibility. For example, the greater reported
susceptibility and shorter incubation period of ruminants (compared with
humans in specific regard to anthrax) make them potential sentinel populations
in the event of an attack using an aerosolized pathogen.(23) Another way
to obtain this knowledge is to attend the 2-week USDA Foreign Animal Disease
Diagnostician's Course held several times each year at the Plum Island
Animal Disease Center in New York.
One of the first actions a veterinary
practitioner takes on suspicion of a natural or intentional outbreak of
an important or exotic disease is timely reporting to proper authorities.
Unless knowledge of what diseases are reportable, and to whom, is maintained
before the event, valuable time will be wasted in "reinventing the wheel."
Practitioners should also engage their
human medical counterparts at the local level. Too often, medical providers
at local hospitals and health departments plan for medical surveillance
and response activities without considering the zoonotic and epizootic
diseases that can impact those systems. Veterinarians who have become
active in public health endeavors have been well received by their counterparts
in human health care and have made important contributions to both animal
and human epidemiology.
Finally, veterinary practitioners can
greatly contribute to natural and intentional disaster response efforts
by volunteering for the various federal response teams. Under the National
Disaster Medical System, and an agreement between the AVMA and the USDA,
Medical Assistance Teams (VMATs) were formed to provide assistance
in the control, treatment, and eradication of animal disease outbreaks.
Comprised of volunteer veterinarians, technicians, and support personnel,
VMATs can be called to federal service for up to 14 days as "special needs"
employees of the US Public Health Service. If activated, VMAT personnel
are paid a salary and also receive various associated benefits.(24)
Another opportunity to contribute to
the early response and control efforts for a veterinary emergency is the
regional emergency animal disease eradication organization. This response
capability consists of 2 regional task forces comprised of USDA employees,
state veterinarians, military support personnel, and industry liaisons.
Information on these service opportunities, as well as printed material
on foreign animal diseases, can be obtained from USDA-APHIS-VS-Emergency
Academicians—As stated, most
veterinary students receive more training on epidemiologic affairs than
do most medical students. However, this effort could be enhanced by including
and standardizing the basic tenets of disease causation and surveillance,
outbreak investigation, population sampling and biostatistics, study design
and evaluation, and effective risk communication.
Zoonotic and foreign animal diseases
are other areas currently taught with various degrees of success. Zoonoses,
representing the main interdigitation between animal medicine and human
medicine, wax and wane across major species boundaries as a result of intricate
social and evolutionary subtleties. The realization of Dr. Calvin Schwabe's
visionary "one medicine"(26) can be achieved only through a clear understanding
of their processes and control strategies. As for foreign animal diseases,
their names say it all. Graduates of US veterinary colleges in the past
several decades likely have not seen any cases of diseases such as FMD,
classic swine fever, and rinderpest. However, all of these diseases are
prevalent over much of the globe and could certainly reappear within our
borders without warning. Although no conceivable outbreak scenario suggests
the possibility of a general shortage of the American food supply, serious
economic ramifications would result from the reintroduction of an OIE list
Finally, the safety and wholesomeness
of our food supply has been a major factor in America's relative international
affluence. Veterinarians play an increasingly important role in
this ever-evolving "farm to fork" continuum, and their basic and continuing
educational needs must be met with the same degrees of completeness, flexibility,
State and federal government—Although
agriculture comprises more than 13% of our national gross domestic product
and nearly 17% of employment,(27) it was not included in the first round
of presidential decision directives addressing potential bioattacks.(28)
In the past 5 years, however, there have been gradual improvements toward
its parity with the public health community regarding the preparation for
an attack and the subsequent recovery. For this to continue, agriculture
leaders must be proactively assertive in their dealings with counterparts
in the law enforcement, defense, public health, and intelligence communities.
Although all states have veterinarians
in key positions throughout their agriculture departments, not all have
positions for public health veterinarians. The establishment of
these positions in every state would facilitate necessary cross communication
with the human medical community and contribute to a true medical surveillance
In conjunction with veterinary educators,
state and federal government must implement training opportunities on the
recognition, prevention, and control of foreign animal diseases. This could
be facilitated through an initial and ongoing accreditation process.
To further an effort already begun,
state and national laboratories must be upgraded to a level where they
can provide timely diagnostics and research on preventions and therapies
against likely natural and intentional disease agents. These laboratories
must also be seamlessly connected into the human-animal disease reporting
system, with both trunks leading to an appropriate endpoint, such as the
CDC or the newly created National Office of Homeland Security.
must be levied against those who plan or promulgate attacks against US
agriculture. Although the recently signed Animal Health Protection Act,
which substantially increases the penalty for each threat or attack against
agriculture and updates and consolidates animal quarantine laws, is a step
in the right direction, current laws may not adequately contribute to an
effective deterrent against such activity. Therefore, all future antiterrorism
legislation must include agricultural commodities as worthy of protection.
The vast capabilities of the US military
are increasingly becoming known to, and drawn upon by, the national emergency
response phases of crisis and consequence management. Some of these capabilities
(veterinary and public health) can specifically contribute to the response
against an attack on agriculture. Others (logistics and communications)
represent key support capabilities necessary for effective disaster management.
Regardless of the expectation for military involvement, these resources
must be specifically tasked and therefore manned, equipped, and trained
in advance of their requirement.
Unfortunately, our ability to prepare
for and respond to intentional biological events may continually lag behind
those of motivated, intelligent terrorists. Therefore, our goal should
be to prepare our resources and ourselves as best we can to minimize the
effects of those events through continual training, exercise, and vigilance.
Programs, Riverdale, Md.
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