Because of space constraints,
this excellent, timely paper has been edited by ASA. The
full copyrighted paper will be provided by either e-mail
or hard copy at no additional cost, upon request, to ASA
Newsletter subscribers.
Defense Against Biological Terrorism
by Torsten Sohns
German Armed Forces Medical Academy
Neuherbergstr. 11, D - 80937 Munich
This article examines the possible dangers to
civilians posed by biological warfare (BW) agents in the
hands of terrorists, "bioterrorism" and
provides suggestions on appropriate defensive measures.
Bioterrorism is a reality, for which, unfortunately, most
countries are ill prepared. Although top priority must be
given to ensuring that bioterrorism does not happen, it
is equally important to enhance readiness for BW defense.
In many countries bioterrorism defense is not the duty of
the armed forces, but the responsible state agencies must
rely on them because of their expertise in BW defense
activities, and, because most qualified full-time
biodefense experts are in the armed forces.
1. BIOTERRORISM RISKS
When estimating the risks of bioterrorism, we look at
both the characteristics of possible risks and the
probability of such an occurrence. The bioterrorism risk
is a function of the presence of terrorists and the
probability that they possess the ability to employ a BW
agent. A risk exists if there are terrorists who have
access to BW agents. Additional risk factors include the
existence of vulnerable targets and the potential damage
that can be inflicted. The risk becomes a threat once
terrorists have specific intentions of employing BW
agents. Such intentions may be the result of
international and sociopolitical interactions or the
personal situation of a lone fanatic. Have terrorists
(either state sponsored or organized groups or
individuals) ever succeeded in gaining possession of BW
agents? Unfortunately, the answer to this question is
yes. There have been several examples around the world in
the 1980s and 1990s: in Paris Clostridium botulinum
cultured by the West German Red Army Faction; [1]; in
northwest Oregon, USA, deliberate salmonella bacteria
contamination of food in restaurants [2]; across the
border from Alaska to Canada, ricin smuggled [3,4,5,6];
in the USA, individual ordering of Yersinia pestis from
American Type Culture Collection [7]; in Tokyo, the Aum
Shinrikyo sect prepared to use anthrax spores and
botulinum toxin. An exhaustive review was published by
Carus. [8] The US FBI at any given time has about 50 to
60 ongoing investigations connected with bioterrorism.
[9] There is no question that vulnerable targets exist.
Even the response to a bioterrorist threat is time and
labor intensive. In one incident, 800 people were
quarantined inside of a nightclub for hours. In another
incident, 24 December 1998, 200 people in a shopping
center had to remove their clothes and be rinsed with
bleach. [10] The response to such threats is real and
must be implemented before determining whether or not the
threat is real or a hoax.
1.1 Distinctive Characteristics of BW Agent
Operations
BW agent attacks can cover a wide area. Dissemination
experiments involving microorganisms conducted several
decades ago showed that an area of 100,000 km2 could be
contaminated without difficulty from an airplane. BW
attacks can be carried out covertly. BW agents can be
combined with radionuclides and chemical agents, which
would complicate identification and treatment of the
agents. For example, UNSCOM [11] sources have reported
evidence that Iraq was prepared to add BW agents to
chemical weapons. Unlike other weapons, BW agents mimic
naturally occurring diseases. A BW attack may be formally
proven only after natural causes for any unusual cases of
disease and death have been ruled out. BW agents
propagate and can cause epidemics. No other warfare agent
can multiply after it has been used. Animals (humans,
too) can become reservoirs and carriers of pathogens and
contribute to the preservation, spread or formation of
new epidemic centers.
1.2 Accessibility of BW Agents
Particularly virulent and environmentally resistant
strains of dangerous pathogens can be suitable as BW
agents. The majority of them occur naturally in animal
reservoirs. When used as a BW agent, the pathogens are
likely to be dispersed as aerosols to quickly infect the
greatest number of people. Victims would be infected
through their respiratory tract, probably by a massive
dose of BW agent. Dangerous poisons of biological origin,
toxins, are also suitable. Botulinum toxin, for example,
is about 15,000 times more poisonous than the deadliest
chemical agent, VX, and 100,000 times more poisonous than
sarin. [12,13] Table 1 lists the "Dirty Dozen"
toxins and diseases suitable as BW agents for terrorist
actions. Others are possible, but these are the ones with
properties most suitable for release or dispersion in
weapons of mass destruction (WMD). This table does not
include other agents capable of killing or damaging
plants and animals. These agents, which are not dangerous
to man, may be used for economic motives. To evaluate the
risks posed by bioterrorism, it is important to estimate
the capability of potential perpetrators to gain
possession of such pathogens and toxins. The agents vary
from the relatively easily produced ricin to bacteria and
to specialty viral agents. Specially trained technicians,
under carefully controlled conditions, can produce viral
agents. There are also limitations to the use of
bacterial pathogens, but these are easier to overcome.
Although many pathogens are present naturally, it is
difficult to obtain an especially virulent and
environmentally resistant strain of a given pathogen.
Having acquired the pathogen and learned how to
mass-produce it, the perpetrators would then have to
decide, whether or not to use it in crude form and accept
what in military terms would be low efficiency but for
terrorist purposes would probably sufice. The other
choice would be to refine the agent, i.e., to dry the
pathogens and process them into an inhalable dust. The
particles must be coated to protect them in the air so
that they can drift for many kilometers. This choice
requires sophisticated skills and equipment, but a
determined individual or groups would be able to
accomplish this.
1.3 Dissemination systems for BW agents
Knowledge of the logistic capabilities and likely
dissemination systems of potential perpetrators also
provides useful information for risk evaluations.
Aircraft, in particular agricultural airplanes with
spraying equipment, drones, ground and marine vehicles,
can be used by terrorists to disseminate BW agents. On
the ground, aerosol generators could be carried almost
anywhere in a covered automobile trailer. No one would
notice if, for instance, anthrax spores were blown into
the central air-conditioning unit of a mall or an office
building. Drinking water supply systems can also be used
to disseminate BW agents. Not all BW agents can be
removed or deactivated with normal purification systems,
including boiling.
1.4 Potential Perpetrators
Fortunately so far there have been only a few uses of
bioterrorism. [14] In general, political or fanatical
motives may prompt the use of bioterrorism. We can
estimate the risk of bioterrorism by correlating the
background of potential terrorists and their access to BW
agents. Table 2 lists the category of terrorism along
with the likely motives for using bioterrorism. According
to unclassified literature, some 15 countries are
suspected to be conducting biological activities at
variance with the Biological and Toxin Weapons Convention
(BTWC). [15] These countries are listed in Table 3. [16]
Information is available about the pathogens and toxins
that are being worked on in so-called "rogue
countries." Several of these countries are also
suspected of supporting international terrorism. The
nationality of terrorists could therefore tell us
something about the BW agents to which they have access.
On the other hand, these countries would come under
immediate suspicion if a terrorist attack employed a BW
agent presumed to be in their arsenal. This may pose a
considerable political, economic and military risk for
such states. For this reason, there is a strong motive
for most states to not supply terrorists with BW agents.
Risk estimates are even more difficult when evaluating
the BW capabilities of terrorist groups, sects or even
individuals. The capability of these groups to acquire or
produce BW agents has been verified by events in Japan
and the USA. [19]
1.5 Potential Targets
Finally, an assessment of risks must also include an
analysis of potential targets. Terrorist attacks are
likely to be directed at major cities, areas of
particular significance for the economy, transport or the
military (e.g., trade fairs, shopping malls, ports,
airports), assembly facilities (e.g., municipal halls,
sport stadiums) and artificially ventilated buildings
(e.g., government, parliament or court buildings and,
most particularly, subway systems). [20] Even individuals
can be the targets of insidious BW agent attacks. [21]
1.6 Dangers to the General Public
What are the risks and dangers posed to the general
public? The effects of BW agents vary considerably. Some
pathogens and toxins can cause fatal diseases, as in the
case of pulmonary anthrax or botulism, but are not
necessarily infectious. There are, however, BW agents
that cause communicable diseases and can trigger
epidemics. Smallpox poses such a danger. Because
systematic vaccination against smallpox has ceased, any
epidemic resulting from a smallpox bioagent will spread
rapidly and be highly lethal, unless immediate quarantine
measures and vaccination to prevent the infection from
spreading are taken. Other pathogens, such as Q fever,
would incapacitate but not kill their victims, unless
they were immunocompromised. How much would a terrorist
need? In 1970 an expert commission of the WHO published
model calculations for the dispersion of 50 kg of anthrax
spores, sprayed from an airplane over a city with 500,000
inhabitants. [22] This model predicted 95,000 dead and
125,000 cases of illness or 50 kg of anthrax spores would
kill almost one-fifth of the inhabitants; these losses
are comparable to those inflicted by an atomic bomb
attack. At the beginning of the Gulf War, Iraq had
produced and weaponized 6000 to 8000 kg of anthrax
spores, as well as 19,000 kg of botulinum toxin. [23]
Iraq produced more than 100 times the amount of anthrax
as in the model calculation. The whereabouts of these
weapons have not been determined or explained.
2. COUNTERMEASURES FOR BIOTERRORISM
2.1 Prevention
Through continuous monitoring, analysis and evaluation of
suspicious activities, people, organizations and states,
by intelligence services and biodefense experts, we can
better recognize the dangers posed by bioterrorism. This
knowledge increases our chances of preventing terrorist
actions. It helps recognize, at an early stage, the
intentions of terrorist groups and unaffiliated
individuals. Close international and national cooperation
among intelligence services and criminal investigation
departments, with the expertise of BW defense experts, is
necessary. In most countries, there is only a handful of
scientifically trained people, working full-time on BW
defense. With few exceptions, they are armed forces
personnel.
2.2 Operational Control
Once the threat or use of BW agents has occurred,
operational control must be given to a center with
clearly defined responsibilities and powers, already
established at the highest appropriate level. Details of
the operations should have been rehearsed before an
actual threat occurs. Biodefense experts should be
immediately available to the operations center. BW agent
aerosols can be disseminated over large areas. For this
reason, as in a radiological crisis situation, immediate
information exchange with neighboring countries may be
necessary. This, along with the necessity of coordination
operations and resources across multiple agencies and
jurisdictions requires the center to be at the highest
level.
2.3 Situation Assessment
Information coming from ambulances, hospitals and
emergency rooms may provide the first indications of a
bioterrorist attack. Patient symptoms and the results of
initial laboratory tests will give preliminary
information about the type of BW agent used. By asking
patients about their whereabouts at the presumed time of
exposure, it is possible to roughly establish the area of
use and the zones of dissemination of the BW agent. As
soon as possible, it must be determined whether a
communicable disease is involved and which areas are
still or already contaminated or endangered. Local
residents must be warned and, if necessary, evacuated or
quarantined.
2.4 Outbreak Management
In the case of the threatened or actual release of
communicable disease agents, the operations control
center must prepare or carry out effective outbreak
management. This includes the planning and control of all
necessary anti-epidemic measures. The timeliness and
quality of these measures can control an epidemic and
prevent a secondary epidemic.
2.5 Public Relations, Evacuation, Traffic
Control and Vulnerable Point Protection
To prevent panic and avoid confusion, only the operations
center should provide information to the public. In the
event of an unspecified BW terrorist threat, vulnerable
point protection should concentrate on ventilation
systems of densely populated buildings, as well as on
infrastructure of central water supply systems.
2.6 Biological Agent Detection and
Identification
The rapid identification of contaminated areas is
critical to assessing the situation and deciding
appropriate action. For this purpose, detection teams
must inspect the areas in question for traces of BW
agents. However, satisfactory methods for rapid detection
and identification of BW agents is still a long way off.
2.7 Medical Treatment
Many doctors are unfamiliar with the symptoms and
treatments for the "Dirty Dozen" toxins and
diseases. Treatments can vary from vaccinations, to
antisera, antibiotics, antidotes, supportive treatment
and isolation. The simultaneous occurrence of a large
number of serious cases will result in logistical and
infrastructural bottlenecks. These may be aggravated by
the need for heightened protection and isolation measures
to prevent secondary epidemics and by loss of medical
personnel and transport problems caused by panic. It is
critical that biodefense experts help train and be a
resource for the civilian medical system. It is also
important that rapid logistical access to medicines,
including vaccines, sera, antibiotics, etc., be
coordinated by a national authority that will report to
the operations center.
2.8 Verifying a BW Attack
If unusual diseases and deaths occur, there are two main
questions. First, what is the identity of the pathogen or
toxin? And second, are the diseases or deaths the result
of a BW agent or do they have a natural cause? Rapid
identification is required so that specific
countermeasures can be taken. Even if someone claims
responsibility for a BW agent attack, government bodies
must still conduct a critical examination of the case and
look for concrete evidence. This is important to
assessing the situation and making decisions about
further action. Verification results may be used to
justify serious political or even military measures. To
clarify this scenario, there must be close and
professional cooperation between a wide variety of
personnel and resources, in particular biodefense
experts, health care services, police and intelligence
services. The first indications of a BW agent attack can
appear within a few hours in hospitals, when physicians
are suddenly confronted with a large number of patients
all showing synchronized symptoms of an unusual, largely
unknown disease. Further important data for the
identification of the pathogen or toxin will come later -
after days and, in some circumstances, even after a delay
of months [24-25] - from domestic and foreign
laboratories in which identification or differentiation
has been conducted. In addition to analyzing air, water,
soil and other samples, particular attention must be paid
to human and animal specimens including corpses,
carcasses, parasites and vectors. Special training and
equipment are required for collecting and evaluating
samples. Such diverse analyses necessitate special skills
and safety requirements that may not always be available
in the country. Verification of a pathogen strain, which
has never before appeared in the region concerned, can be
a particularly powerful piece of evidence indicating a
possible BW agent attack.
2.9 Other Countermeasures
Many more measures must be addressed. Because of space
constraints, only the most important ones are highlighted
here: Individual protection, collective protection,
hardening of equipment, decontamination, marking,
cordoning off and guarding hazardous areas, technical
warning systems, and support provided by the armed
forces.
3. PROPOSALS FOR AN ANTI-BIOTERRORISM PROGRAM
Biological terrorism is a reality. The chances of it
occurring now are greater than they were in the past. The
question is no longer whether, but when. The
vulnerability of our highly civilized and technological
world to bioterrorism is considerable. If it is difficult
to protect armed forces in operations against BWs, then
protecting the civilian population poses even greater
problems. Conceptual gaps and financial deficits are
clearly evident. Prevention and mitigation arethe two
keystones in any bioterrorism countermeasures program.
3.1 Prevention
Political means first must be used to eliminate the
causes of terrorism, to prevent the development,
production and stockpiling of BWs and to monitor the
proliferation of BW technology by non-proliferation and
export control measures. National intelligence services
must cooperate in the pursuit of suspicious persons and
material worldwide. In cooperation with friendly
countries, we must support the Russian government in
converting the former Soviet military BW research and
production facilities. This will help to reduce the
number of former BW scientists who might need to go
elsewhere or sell their expertise and equipment in order
to support their families. [26,27] Furthermore, access to
potential BW components should be made difficult on both
the international and national levels: First, export
control measures can help counter the risk of misuse of
biological substances and dual-use equipment. Such
material and equipment should only be supplied to
countries which are known to comply with the Biological
and Toxin Weapons Convention and allow inspectors free
access. Second, on the national level, authorities
issuing handling or export permits for dangerous
pathogens or approving the operation of laboratories with
enhanced safety, need training and regular information
updates on the military and dual-use technological
activities and uncovered cases of biological terrorism.
The same applies to customs authorities, law enforcement
agencies, relevant industrial associations, and
scientific institutes. Finally, training programs for
intelligence personnel and criminal investigation
officers can improve prevention. Their agencies must work
closely together in an effort to prevent bioterrorism.
3.2 Mitigation
Prevention reduces but does not eliminate risks.
Consequently both civilian authorities and the armed
forces must be prepared to take necessary action to avert
hazards in the event of a threat or actual use of BW
agents by terrorists. Using their BW defense experts, the
armed forces should provide training programs for police
officers, firefighters, key law enforcement and health
personnel, as well as for relevant personnel from
governmental and non-governmental aid organizations (e.g.
Red Cross). Studies should be commissioned to analyze
possible bioterrorist scenarios, identify particularly
vulnerable points (e.g., the ventilation systems of large
buildings, malls, etc.) and find the best ways of
preventing and dealing with bioterrorist attacks.
Civilian and military authorities must keep each other
informed about their capabilities. Action by civilian
authorities and the armed forces must be planned,
coordinated and exercised together. Appropriate judgement
and action in the face of BW hazards is possible only
with the support of BW defense experts. In most
countries, political and administrative decision makers
are dependent on the expertise of the armed forces. The
necessary funds must be apportioned to the armed forces.
Vaccination policy remains an open issue. Since highly
contagious diseases may rapidly spread worldwide,
vaccination policies should be dealt with on an
international basis. An initiative should be started to
aim at ensuring the timely availability of licensed
vaccines in sufficient quantities when needed as well as
a common approach for vaccination. This includes such
issues as vaccination of medical emergency crews,
availability of e.g. smallpox vaccine for containing an
epidemic and others. In most countries there are far too
few facilities for the special diagnosis and therapy of
dangerous, communicable diseases, regardless of possible
cause. The same applies to the transport of highly
contagious patients. Disaster prevention should give a
high priority to determining the required number and
location of biosafety level BL3 and BL4 facilities.
Urgent research and development requirements include
automatic detection and monitoring systems, expansion of
the spectrum of detectable BW agents, shortening of the
detection time, and improving the specificity and
sensitivity of methods. Rapid and effective prophylactics
and therapeutic modalities must be found for all relevant
BW agents. [28] An open and balanced information program
about the dangers of BWs and their proliferation, as well
as on the requirements for funding and the progress of
counterprograms should be instituted. In many countries,
increased budgeting is mandatory for counterprograms to
improve understanding and reduce the risks and
probabilities of bioterrorism attacks.
Key Words: Risk, NBC, biological, chemical,
proliferation, bioterrorism, casualty, resources, medical
personnel, medical materiel, decontamination
About the author: Colonel Sohns is a medical officer
with the German Armed Forces. In the recent past he has
worked in the fields both of medical planning and policy
and of NBC medical defense. He is currently Deputy
Commander of the German Armed Forces Medical Academy.
Prior to this, he was assigned to the German Ministry of
Defense and to NATO's Supreme Headquarters Allied Powers
Europe (SHAPE).
Ed. Note: Col. Sohns' previous paper, which was
published in ASA issue 99-3 (June 1999), provided an
in-depth study on the proliferation of weapons of mass
destruction. Our thanks to Col. Sohns for both studies;
they greatly add to our baseline of understanding across
these critical areas.
REFERENCES
- R. Purver (Canadian Security Intelligence
Service), "Chemical and Biological
Terrorism: The Threat According to the Open
Literature," printed as a manuscript, June
1995
- T.J. Trk et al, "A Large
Community Outbreak of Salmonellosis Caused by
Intentional Contamination of Restaurant Salad
Bars," JAMA, 6 August 1997, Vol. 278, No. 5,
389-395
- In theory, 1 g of ricin is enough to kill over
1000 people
- J. Kifner, "Man is Arrested in a Case
Involving Deadly Poison," New York Times, 23
December 1995
- J. Stephenson, "Confronting a Biological
Armageddon: Experts Tackle Prospect of Bioterror-
ism," JAMA, 7 Aug 1996, Vol. 276, No 5,
349-351
- Personal statement by a representative of the US
Naval Medical Research Institute (NAMRI) on 29
April 1997
- Health Letter of the Centers for Disease Control
(CDC) Atlanta, 29 May / 5 June 1995, p. 5
- W. Seth Carrus, "Bioterrorism and
Biocrimes" - The Illicit Use of Biological
Agents in the 20th Century", Center for
Counterproliferation Research, National Defense
University, August 1998 (March 1999 Rev.) 9.
Statement by R. Blitzer, Chief FBI Domestic
Terrorism and Counterterrorism Planning Section,
In ABC News Prime Time Live show, USA, 25
February 1998, transcript available under
http://www.infowar.com/WMD/wmd_030298a_s.html-ssi
- The Lancet, Vol. 353, 9 January 1999, p. 130
- United Nations Special Commission
- "Medical Management of Biological
Casualties," Handbook, US Army Medical
Research Institute of Infectious Diseases, Fort
Detrick, MD, March 1996
- In theory, 1 g of botulinum toxin is enough to
kill over 10 million people
- Initial studies appeared on the question as to
why biological weapons have played only a minor
role in the arsenal of terrorists. Cf. R.
Purver,"Understanding Past Non-Use of
Chemical and Biological Warfare Agents by
Terrorists," presentation to the conference
on "ChemBio Terrorism: Wave of the
Future?" sponsored by the Chemical and
Biological Arms Control Institute, Washington,
D.C., 29 April 1996
- Convention on the Prohibition of the Development,
Production and Stockpiling of Bacteriological
(Biological) and Toxin Weapons and on their
Destruction of 10 April 1972
- Prepared by the Office of Technology Assessment
(OTA), 1993, from various sources; US Congress,
Office of Technology Assessment, Proliferation of
Weapons of Mass Destruction: Assessing of Risks,
OTA-ISC-559, Washington, D.C.: US Government
Printing Office, August 1993
- Cf. R. Preston, "The Bioweaponeers",
The New Yorker, 2 March 1998;
http://jya.com/bioweap.htm
- Cf. Ken W. Alibek, Stephen Handelman
(Contributor), "Biohazard. The Chilling True
Story of the Largest Biological Weapons Program
in the World - Told From Inside by the Man Who
Ran It." Random House Inc., New York 1999
- J.P. O'Neill (FBI), statement, Hearing on
Terrorist Use of Nuclear/Biological/Chemical
Agents, Permanent Subcommittee on Investigation,
United States Senate, 1 November 1995
- Cf. L.A. Cole, "Clouds of Secrecy: The
Army's Germ Warfare Tests over Populated
Areas," Totowa, N.J., 1988 and by the same
author "The Eleventh Plague: The Politics of
Biological and Chemical Warfare," New York,
1997
- R. Purver, (endnote 1)
- Health Aspects of Chemical and Biological
Weapons, WHO, 1970
- Information of the Security Council of the United
Nations on 25 August 1995 by the Chairman of the
United Nations Special Commission (UNSCOM),
Ambassador Ekeus
- On the basic problems here, see Nilesh Parmar,
"It was the plague, or was it?" India
Today, 30 November 1994
- Cf. T. Sohns "The Proliferation of Weapons
of Mass Destruction - A Challenge for Decision
Makers" in the ASA Newslatter 99-3, 11 June
1999
- Cf. R. Preston, (endnote 17)
- J. Matloff, "Danger from Russia's
Scientists: Selling Weapons Know -How", The
Christian Science Monitor, 13 February 1998;
http://www.csmonitor.com/durable/1998/02/13/intl/intl.4.html
- A survey of the problem of licensing vaccines and
other drugs can be found in Steve Sternberg,
"Bottle-neck Keeps Existing Vaccines off the
Market," Science, No. 266, 7 October 1994;
also E.J. Finke, et. al., "List of Vaccines
and Immunoglobulins for Prevention of Potential
B-Agents", German Armed Forces Medical
Academy, Department of Studies and Science,
Institute for Microbiology, Munich, manuscript
presented at the Third Biological Medical Defense
Conference of the German Ministry of Defense,
October 1996. According to the revelations of K.
Alibekov, formerly the first deputy chief of
research and production for the Soviet biological
weapons program until his defection to the USA in
1992, "52 biological agents would be used in
biological weapons". Alibekov made this
statement in ABC News's PrimeTime Live show, USA,
25 February 1998.
- J.D. Douglass Jr., "Weapons of Mass
Destruction - A Biological Weapons Threat Worse
Than Saddam", 10 March 1998;
http://www.infowar.com/WMD/wmd_032698a_j.html-ssi
Table 1. "Dirty Dozen" toxins and
diseases.
| Bacteria |
Viruses |
Toxins |
anthrax
plague
tularemia
glanders and meliodosis
brucellosis
Q fever |
smallpox
viral encephalitis (e.g., VEE)
viral hemorrhagic fevers(e.g., Marburg) |
botulinum
toxin
ricin
staphylococcal enterotoxin B |
Table 2. Motives in Terrorism
| Terrorism Category |
Motivation |
| State sponsored and controlled |
political |
| Groups and sects |
political or fanatical |
| Individuals |
fanatical |
Table 3. Proliferation Risks: Suspected
Biological Weapons Programs
Country
|
Carus
(policy paper)
|
Harris
(USG officials)
|
Guardian
(London)
|
McGeorge
(Def & FA)
|
FIS
(1993)
|
ACDA
(1993)
|
Total
|
Percent
|
| Libya |
+ |
+ |
+ |
+ |
+ |
|
5 |
71 |
| North Korea |
+ |
+ |
+ |
+ |
+ |
|
5 |
71 |
| Iraq |
+ |
|
+ |
+ |
+ |
+ |
5 |
71 |
| Taiwan |
+ |
+ |
+ |
|
|
+ |
4 |
57 |
| Syria |
+ |
+ |
+ |
|
|
+ |
4 |
57 |
| Russia (Soviet
Union) |
+ |
|
+ |
+ |
|
+ |
4 |
57 |
| Israel |
+ |
|
+ |
+ |
+ |
|
4 |
57 |
| Iran |
+ |
+ |
|
+ |
+ |
|
4 |
57 |
| China |
+ |
+ |
+ |
|
|
+ |
4 |
57 |
| Egypt |
|
|
+ |
|
+ |
+ |
3 |
43 |
| Vietnam |
|
|
+ |
|
|
|
1 |
14 |
| Laos |
|
|
+ |
|
|
|
1 |
14 |
| Cuba |
|
|
|
+ |
|
|
1 |
14 |
| Bulgaria |
|
|
|
+ |
|
|
1 |
14 |
| India |
|
|
|
|
+ |
|
1 |
14 |
|