Biological Warfare — An Emerging Threat
Reshma Agarwal*, SK Shukla**, S Dharmani***, A Gandhi***
As we approach the 21st century, there is an increasing worldwide awareness and threat regarding theuse of biological warfare agents both for war and terrorist attack. Biological agents include microorganismsor biological toxins that are used to produce death in humans, animals and plants. They are characterizedby low visibility, high potency, substantial accessibility and relatively easy delivery. Biological warfareagents are unconventional weapons that can be delivered by unconventional means like aerosol sprays,food and water contamination, conventional explosive munitions or by covert injections. Because oftheir concealed delivery, easy transportation and difficult identification they are readily adaptable forterrorist operations or to gain political advantages. The detection of such attack requires recognition ofthe clinical syndromes associated with various biological warfare agents. Diagnosis can be made onclinical grounds and on investigations. Protective measures can be taken against biological warfare agents. These should be implemented early (if warning is received) or later (once suspicion of agent use ismade). After the confirmation of diagnosis emergency medical treatment and decontamination areperformed in rapid sequence. Patients are then evacuated and specific therapy is given according to theagent involved. Appropriate emergency department and hospital response could significantly limit themorbidity and mortality of biological warfare agents.
INTRODUCTION
treatment and for prophylaxis of exposed persons. Environmental pollution could pose continuing threats. We
Biological warfare has been waged intermittently for nearly have tried to present in this article a comprehensive review
2,500 years1 and the deliberate use of microorganisms
on biological warfare and its consequences.
and toxins as weapons has been attempted throughout thehistory. Biological warfare has evolved from the crude use of
HISTORIC BACKGROUND
cadavers to contaminate water supplies to the development
The history of biological warfare is difficult to assess
of specialized munitions for battlefield and covert use. The
because of a number of confounding factors. These include
modern development of biological agents as weapons has
difficulties in verification of alleged or attempted biological
paralleled advances in basic and applied microbiology. These
attacks, the use of allegations of biological attacks for
include the identification of virulent pathogens suitable for
propaganda purposes, the paucity of pertinent microbiological
aerosol delivery and industrial scale fermentation process to
or epidemiological data and the incidence of naturally
produce large quantities of pathogens and toxins.2 Biological
occurring endemic or epidemic diseases during hostilities.2
weapons are cheap, can cause mass casualties and arerelatively easy to produce, even by developing nations. Long
The use of biological agent is not a new concept2 and
standing sources assign the following costs to prosecute a
history is replete with examples of biological weapon use.
war : conventional arms $ 2,000/Km² vs chemical weapons $
Attempts to use biological weapons date back to antiquity.
600 /Km² vs biological weapons $1Km².3 These factors have
Scythian archers infected their arrows by dipping them in
led to the attraction of terrorist groups as well to chemical
decomposing bodies or in blood mixed with manure as far
and biological weapons. The deployment of these agents is
back as 400 BC.1 Persian, Greek and Roman literature from
no longer a hypothetical scenario but a life-threatening
300 BC quote examples of the use of animal cadavers to
contingency. It presents serious challenges for patient
contaminate wells and other sources of water.
In 190 BC, at the battle of Eurymedan, Hannibal won a
naval victory over King Eumenes II of Pergamon by firing
*Associate Professor; **Director, Professor and Head; ***Post
earthen vessels full of venomous snakes into the enemy ships.
Graduate Student, Upgraded P.G. Department of Medicine, MLNMedical College, Allahabad (U.P.)
In 18th century AD, British forces distributed small pox
Received : 13.4.2004; Accepted : 20.6.2004
infected blankets to native Americans to create transmission
of disease. During First World War, Germans developed
and produce mass casualties or as plant pathogens to destroy
anthrax, glanders, cholera and a wheat fungus for use as
crops, devastate the food chain and cause famine.
biological weapons.4 Likewise, during Second World War,
Contamination of food and water is another mode of delivery
Japanese operated a secret biological warfare research and
to targeted population. The use of biological warfare agents
carried out human experiments with plague, anthrax, syphilis
has far reaching consequences. The threatened use of BW
on Chinese prisoners.4 In 1940s and 50s, United States and
agents can result in fear and panic in a population, whether
Britain continued research on various offensive biological
under attack or being threatened to gain political advantages
weapons like anthrax and botulinum toxin and also continued
in political activities. The stress associated with a biological
to the 60s. In 1970s, USSR and is allies were suspected of
attack could create high numbers of acute and potentially
having used yellow rain (trichothecene mycotoxins) during
chronic psychiatric casualties.9 Because of their concealed
campaigns in Cambodia and Afghanistan, which caused
delivery, easy transportation, difficult identification and easy
alimentary toxic aleukia (ATA) in civilians.5 In 1979, 66 people
escape of performer before BW agent release is apparent,
were killed due to accidental release of anthrax from a weapons
they are readily adaptable for terrorist operations. They may
facility in Sverdlovsk, USSR.6 Since the 1980s, terrorist
also be employed during political events (especially
organizations have become users of biological agents. The
multinational events)10 to create injury or political disorders.
most frequent bioterrorism episodes have involved
Modes of Delivery
contamination of food and water. In September, 1984,
BWA are unconventional weapons and can be delivered
international contamination of restaurant salad bars in Oregon
by unconventional means. The most effective method is
by followers of Bhagwan Rajneesh infected 751 persons with
aerosol sprays (most likely to be used by terrorists and military
Salmonella typhimurium.7 Recently, in a short span of time,
groups), because of their particle size (1-5µm) due to which
i.e. from Sept. to Nov. 2001, 23 cases of bio-terrorism occurred
they are most efficiently delivered to their target (air sacs of
in US which mostly involved, postal workers, where letters
lung).11,12 Aerosol generators, generate particle of optimal
contaminated with anthrax were handled or opened.
size and deliver aerosol via point source (fixed aerosol devices
Definition
with sprayers) of line source (such as moving vehicle, airplane,
Biological weapons or biological warfare agents include
boat). Other modes of delivery are food and water
microorganisms or biologic toxins that are used to produce
contamination, conventional explosive munitions and by
death or disease in humans, animals and plants.5 The ability
of infectious agent to cause widespread illness and thus to
Portal of Entry
cause societal disruptions and panic, together with low cost
These BW Agents mainly enter through respiratory tract
of these agents led to their being called as “Poor Man’s
(following inhalation of aerosolized BWA). Others routes are
exposed mucosal surfaces, (nose/mouth/eyes), GIT (through
Desirable biological weapons are characterized by low
contaminated food and water), intact skin (barrier against
visibility, high potency, substantial accessibility and relatively
most BWA except mycotoxin) and injection (traumatic
easy delivery (as an aerosol with particle diameter size 1-
Environmental Detection Classification of Biological Warfare Agents (BWA)
Currently no reliable detection system exists for BWA.
The biological warfare agents can be classified as :
Biological Integrated Detection System (BIDS), which is
Clostridium perf toxin, Staph enterotoxin B,
a multi-component system that provides monitoring, sampling
detection and presumptive identification. BIDS is vehicle
based and must be located in BW aerosol cloud to detect
Hemorrhagic Fever, Small Pox, Rift Valley Fever,
agents. These technologies use components that
automatically determine the count/size of particle, determine
if particles are living organisms, classify some basic cellcharacteristics using Ag-Ab analysis for identification. A Short Range Biological Standoff Detection System
Saxitoxin (derived from paralytic shellfish)
(SRBSDS), which employs UV and laser-induced
Ricin (cytotoxin derived from caster bean mesh)
fluorescence to detect aerosol clouds. Biological Warfare Agents - Uses and Consequences A Long-Range Biological Standoff Detection System
Biological warfare agents are still used as they were before
(LRBSDS), which employs laser system mounted in a
20th century. The employment of BWA is not limited to war
helicopter to scan, designated area of interest.
alone, but can occur at anytime, at any place and by anyone. Portal Shield System, which consists of network of
They can be employed as weapons of mass destruction.
biological and chemical point detectors, linked to computer/
Aerosols of biological warfare agents may deliver
incapacitating or lethal inocula over large geographic areas
Joint Biological Point Detection System, which is an
inconsistent (e.g., compressed time course)
automatic air-sampling device and provides visual and
Other inconstant elements (e.g., number of cases,
audible alarms in presence of biological warfare agents.
mortality and morbidity rates, deviations from disease
By Examination of Environmental Samples. Point source
munitions will leave environmental residue of BWA near point
Indications of possible BW agent attack include the
Management of Biological Warfare Agent Casualties
Disease entity that is unusual or that does not occur
Recognition of biological warfare injuries.
Multiple disease entities in the same patients, indicating
that mixed agent have been used in the attack
Large number of both military and civilian casualtieswhen such populations inhabit the same area
Data suggesting a massive point-source outbreak
High morbidity and mortality rates relative to the number
Medical personnel must be familiar with signs and
Illness limited to fairly localized or circumscribed
symptoms of BWA casualties and must attempt to distinguish
between epidemic of natural origin and BW attack.
Low attack rates in personnel who work in areas with
CLINICAL RECOGNITION OR DIAGNOSIS
filtered air supplies or closed ventilation systems
Successful management of exposure to BWA relies on
Absence of a competent natural vector in the area of
early recognition. Medical units should rely on information
outbreak (for a biological agent that is vector-borne in
not only from detectors and intelligence sources, but also
from casualties themselves. This applies particularly to BW
Lab Diagnosis
weapons/agents since at present there are no rapid methods
Most of the attacks are clinically recognized.
of identification or detection. Some of the problems in
They are further identified by usual lab tests (microscopy,
recognition and diagnosis of BWA attack are discussed here.
culture, ELISA, mass spectroscopy, animal inoculation
Unlike chemical agents, which typically lead to violent
methods, Ab detection (e.g. IgM), PCR and by detection
disease syndromes within minutes at site of exposure, disease
of metabolic products of infections/toxic agents in clinical
resulting from biological agents have incubation period of
days.14 This attack may not be apparent until days or even
weeks after the attack has occurred. Therefore, the firstindication that a BW attack has occurred may be large number
Triage is done as whether EMT or decontamination
of patients simultaneously presenting with a similar disease.
Such an event could be confused with naturally occurring
Immediate : Casualties who require life saving care within
epidemic. Early identification of BW attack may be further
a short time, when that care is available and of short
confounded by difficulties in early clinical diagnosis. Other
potential confounding factors are, lack of clinical experience
Delayed : Casualties with severe injuries who are in need
with potential BW agents, and possible difference in clinical
of major or prolonged surgery or other care and who will
presentations from a naturally acquired disease versus an
require hospitalization, but delay of this care will not
aerosolized agent. Classic, fully differentiated syndromes may
adversely affect the outcome of the injury.
not be apparent until late in the clinical course. The nature
Minimal : Casualties who have minor injuries, can be
and timing of symptoms will vary with the route of exposure,
helped by non-physician medical personnel, will not be
nature and dose of agent used. Early recognition of first few
evacuated, and will be able to return to duty shortly.
cases of disease enable medical personnel to implement BWdefensive measures.14
Emergency Medical Treatment (EMT)
Preliminary criteria for suggestive outbreaks of disease
EMT and decontamination may be performed in rapid
that could provide indications of a possible biological weapons
sequence. Treatment follows the universally accepted
algorithm of first ensuring the adequacy of airway breathingand circulation.16
Decontamination
Decontamination is the physical process of removing
residual chemicals from persons, equipment and the
Case distribution geographically and/or temporally
Table 1 : Summary of Biological Warfare Agents
severe resp. distress, stridor, resp.
mediastinitis and thoraciclymphadenitis) shock, and deathwithin 24-36 hrs. *Parenchymal infiltrates unusual. *Hemorrhagic meningitis may alsooccur.
lesions at same developmental stage) *Viral isolation,
spreads to lower extremitiesand then to trunk; lesions deeplyseated in dermis. *Death in - 35%.
environment. Every person arriving at Medical Treatment
(c) Patient is placed in PPW (Patient Protective Wrap) for
Facility (MTF) from biological warfare contaminated area is
protection from BWA and should be isolated in designed
considered contaminated unless there is positive proof to
Medical Evacuation
(a) Initial decontamination involves removal from the
After the identification and decontamination of casualties,
contaminated environment, removal of all contaminated
measures must be taken to prevent contamination of
clothes and copious irrigation with water.
ambulance and air evacuation assets. Many BWA casualties
(b) Exposed person is revised with dilute household bleach
may be safely evacuated using basic infection control
guidelines.20 The United States Army Medical Research
Table 1 : Summary of Biological Warfare Agents (contd)
*Streptomycin 30mg/kg IM qdDuration: 60 days unlessvaccinated.
3 days) for serious complications *DOD cell-culture derived vaccinia
released by CDC if smallpoxcase(s) confirmed.
loading dose followed by17 mg/kg IM or IV q 8In mass casualty situation:*Doxycycline 100 mg PO bid:*Ciprofloxacin 500 mg PO bid*Chloramphenicol 1 g IV g6HDuration: 10-14 d days
for serotypes A, B. E. *DOD heptavalent antitoxinfor serotypes A-G.
Institute of Infectious Diseases maintains an aero-medical
isolation team (AIT) which is a rapid response team with
Some of the therapies recommended vary from those found
worldwide aircraft capability. It is designed to safely evacuate
and manage patients with potentially lethal communicable
BW exposure (aerosol) may produce a disease with
disease. It offers portable containment lab and limited
clinical features different from naturally occurring disease
environmental decontamination and specialized consultant
eg. inhalation (BW) versus cutaneous (endemic)
expertise. Indications for deployment include cases of highly
contagious, lethal or unidentified disease including casesfrom suspected BW attack.
An adversary (enemy/opponent) may develop BWAresistant to standard antibiotic therapy. Specific Therapy
Specific Therapy is given according to specific agent given
Prevention
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