Chemical & biological agents-a brief history.

Chemical and biological agents are not modern creations. Early Persians used corpses to foul wells. Indeed in 1346 the Mongols catapulted corpses infected with plague into the city of Caffa during a siege.

World War 1 spawned many chemical weapons and their use. The French introduced tear gas grenades in 1914. The Germans responded in kind. In early 1915 the Germans deployed Chlorine gas against the French and British. 5000 died. Later that year the French and British unsuccessfully used lethal agents.

Three months later the Germans used the blister agent Phosgene against the British, proving to be significantly more effective than Chlorine.

18 months later (1917) Germany overshadowed their success with Phosgene by deploying Mustard Gas, another blister agent. Undoubtedly Mustard gas was the deadliest chemical weapon of World War 1, claiming 400 000 lives.

Since World War1 chemical or biological agents were used

· In 1936 by the Italians against Ethiopia;

· In World War 2 by Japan against China;

· By Germany in World War2, producing and testing nerve agents;

· By US forces in Vietnam in the form of riot control agents and herbicides. The Viet Cong and North Vietnamese also used captured riot control agents;

· In 1978 by the KGB to kill a Bulgarian dissident with Ricin in London;

· In 1984 by Iraq against Iran (Mustard gas & nerve agents);

· In 1995 by the Japanese sect Aum Shinrikyo in the Tokyo underground.

Types of Chemical agents

Chemical agents are chemical compounds used to produce mortality, incapacity or other damage. Some are toxic, others not (i.e. tear gas).

They can be delivered by ground, air and naval weapon systems.

There are these general categories of toxic chemical agents:-

· Nerve agents. The most lethal, even in small doses. They attack the nervous system, disrupting essential bodily functions like breathing, muscle control, vision;

· Blister agents (vesicants). Generally leading to incapacitation, blister agents inflame and blister the skin and damage internal tissues such as the lining of the breathing passages. Fatalities may occur through systemic poisoning or secondary infection;

· Blood agents (Chemical asphyxiants). Still lethal but in larger concentrations than nerve agents, these interfere with the transfer of oxygen from the blood to the tissues; and

· Choking agents. As named, they attack our respiratory system. Like blood agents, they are lethal in larger concentrations than nerve agents.

Important aspects of chemical weapons

They can be delivered in liquid form, aerosol or as a gas. They can enter the body by inhalation, absorption (the agent penetrates the skin or eyes or ingestion) and ingestion (agent is swallowed).

Persistency is a measure of how long the agent is effective for in the target area after release. Agents are either persistent or non-persistent.

A persistent agent is usually a solid or liquid, remaining in the target area to create a contact hazard (i.e. if touched without protective equipment) and may evaporate slowly causing a vapor that lasts for days/months/years.

A non-persistent agent is generally a gas or liquid that evaporates quickly creating a vapor cloud that disperses over minutes/hours/days.

Agent Group

Agent Symbol

Agent Name

State at 20degC

Rate of

Action

Symptoms

Means of Decontamination

Means of Detection

Persistency

Skin Toxicity

Eye Toxicity

Nerve

GA

Tabun

Colourless to brown liquid

Immediate

Pinpoint

pupils,

runny nose, drooling, coughing, tightness

in chest,

muscle

twitching,

jerking,

nausea,

vomiting,

diarrhea, convulsions

and coma.

Bleach slurry or decontaminant chemical agent.

Detector kit and detector paper for liquid droplets.

Several days for liquid

Extremely toxic

Extreme

GB/

GE

Sarin

Colourless liquid

Immediate

Pinpoint

pupils,

runny nose, drooling, coughing, tightness

in chest,

muscle

twitching,

jerking,

nausea,

vomiting,

diarrhea, convulsions

and coma.

Bleach slurry or decontaminant chemical agent.

Detector kit and detector paper for liquid droplets.

Non persistent

Extremely toxic

Extreme

GD

Soman

Colourless liquid

Immediate

Pinpoint

pupils,

runny nose, drooling, coughing, tightness

in chest,

muscle

twitching,

jerking,

nausea,

vomiting,

diarrhea, convulsions

and coma.

Bleach slurry or decontaminant chemical agent.

Detector kit and detector paper for liquid droplets.

Mildly, up to 2 days

Extremely toxic

Extreme

(1)GF

Cyclohexyl

Colourless liquid

Immediate

VX

VX

Colourless liquid to dark brown

Immediate

Pinpoint

pupils,

runny nose, drooling, coughing, tightness

in chest,

muscle

twitching,

jerking,

nausea,

vomiting,

diarrhea, convulsions

and coma.

Bleach slurry or decontaminant chemical agent.

High, up to several weeks

Extremely toxic

Extreme

Agent Group

Agent

Symbol

Agent

Name

State at 20degC

Rate of Action

Symptoms

Means of Decontamination

Means of Detection

Persistency

Skin toxicity

Eye Toxicity

Blood

AC

Hydrogen Cyanide

Colourless gas

Immediate

Loss of consciousness, nausea, vomiting, dizziness,

convulsions apnea and headache.

None needed in

the field.

1.

Smell of

bitter

almond or

peach kernels.

2. Detector kit.

Short

Liquid

slightly

irritating

Liquid slightly irritating

CK

Cyanogen

Chloride

Colourless gas

Immediate

2-5 mins

Coughing, choking, giddiness, nausea, vomiting,

loss of consciousness, apnea, headache,

convulsions and coma.

None needed in

the field.

1.

Very

irritating

to smell.

2.

Detector kit.

Short

Irritating

to skin

Irritating

(1)

SA

Arsine

Colourless gas

Delayed

Very

short

None to

bare skin

None

Vesicant

Mustard

(Blister)

HD

Distilled Mustard

Colourless to pale yellow liquid

Delayed 4-12 hrs

Itchy eyes, nose and throat, nausea, later sometimes nausea and vomiting, hoarseness or hacking cough, redness of skin followed by blisters.

Bleach slurry or decontaminant.

1.

Smell of

garlic or

horse-radish.

2.

Detector kit

and detector paper for

liquid.

Several

days to a

month in

winter

Severe

blistering

Susceptible to low concentration.

Permanent if untreated.

(1)

HN3

Nitrogen Mustard (3)

Dark liquid

Immediate on eyes. Delayed for 12 hrs skin.

Longer

than HD,

indefinite

in winter

Toxic, subcutaneous damage by

liquid

Immediate

Vesicant Arsenical

L

Lewisite

Dark oily liquid

Rapid

May cause systemic arsenic poisoning

Bleach slurry or decontaminant

chemical agent.

1.

Smell of geraniums

2.

Detector kit.

Days,

longer in

winter.

Immediate irritation,

toxic.

Searing pain, permanent corneal damage.

(1)

MD

Methyldichior

Arsine

Colourless liquid

Delayed (blisters)

Immediate eyes

Several

hours.

Blistering

of skin in

hours.

Irritating, permanent damage if not treated.

(1)

ED

Ethyldichloro

Arsine

Colourless liquid

Immediate eyes.

Blistering 2 hrs

Short, up

to 1 hour.

Rapid,

blistering

within 1 hour.

Very.

(1)

PD

Phenyidichlor

Arsine

Colourless liquid

Immediate eyes. 30 mins skin.

Up to 1

day.

Very.

Vapour irritating but not toxic.

Vesicant Urticant

CX

Phosgene

Oxime

Colourless solid

Instantaneous

Violently irritates mucous membrane of eyes and nose, forms weals rapidly.

Not entirely

effective. Wash

with copious

quantities of water.

1.

Intensely

irritating

to smell.

2.

Detector kit.

Indefinite.

Leaves

blanched

area within

30 seconds.

Very, permanent blindness.

Agent Group

Agent

Symbol

Agent

Name

State at 20degC

Rate of Action

Symptoms

Means of Decontamination

Means of Detection

Persistency

Skin Toxicity

Eye Toxicity

Choking

CG

Phosgene

Colourless gas

Immediate in high concentrations.

Symptoms delay 4-12 hrs

Damages lung lining and floods lungs.

None needed in

the field.

1.

Smell of

newly mown

grass.

2.

Detector kit.

Short.

None.

Irritating, not toxic.

Riot Control-Tear

Vomiting

CS

O-chloro-benzal-

Malono-

nitrite

White solid

Immediate

Very irritating. Causes tears, coughing and feeling of burning of skin.

Not necessary,

can be washed

with cold water.

Senses.

Short.

Irritating

non-toxic.

Extremely irritating. Not toxic.

DM

Adamsite

Yellow to green solid

Immediate

Pain in chest and nose, headache, coughing, sneezing and vomiting.

Not necessary,

can be washed

with cold water.

Senses.

Short.

Irritating

non-toxic.

Irritating. Not toxic.

Incapacitating

BZ

3-Quinuclidinyl

Benzilate

White solid

Immediate

Sleepiness, decreases alertness and progressive intoxocation.

None.

Types of Biological agents

A biological agent is a living organism (or a product from them such as a toxin) used to cause disease in people, plants and animals. They may be delivered as aerosols in liquid suspension or powder, in munitions or by spraying (i.e.aircraft).

These agents fall into 5 groups:-

· Bacteria. These are small free-living organisms which produce disease often treatable with antibiotics;

· Rickettsiae. A particular type of bacteria which, like viruses, only grow within living cells. Usually they are vulnerable to broad spectrum antibiotics;

· Viruses. These organisms need living cells to replicate and produce diseases unresponsive to antibiotics but they may respond to antiviral compounds;

· Fungi. Primitive plants that do not photosynthesize, which sustain themselves on decaying vegetable matter and which usually form spores. The diseases they produce often respond to antimicrobials ; and

· Toxins. Poisons produced by micro-organisms, plants and animals.

Important characteristics of Biological Agents

The essential features of micro-organisms as biological agents comprise of pathogenicity, virulence and viability.

Pathogenicity indicates the ability of an organism to create disease. Virulence measures the organism’s ability to overcome or reduce the defensive mechanisms of the body. Viability indicates an organism’s ability to survive its release or storage environment.

Moisture, temperature and light are critical factors affecting the viability of the biological agent. Without moisture, most biological agents will die. Relatively low temperatures (around 5C) are necessary for storing and releasing such agents. This causes a dormant state in these organisms but virulence remains. Upon inhalation, the temperature of the organism increases and it is active once more.

Light is the mortal enemy of most micro-organisms, which cannot tolerate prolonged exposure to sunlight. This fact together with a preference for cooler temperatures means that they are more likely to be used at night.

Biological agents may be spread by aerosol (A), direct contact (D),ingestion(I) or by a vector(V). Vectors are carriers (e.g. mosquitoes) of agents from one host to another.

Interestingly, biological agents are generally ineffective as aerosols unless they are released in a particle size between 1-5 microns.

The fact that biological agents usually have a dormancy period raises difficulties of detecting and containing disease, making them potentially a very devastating agent.

SUMMARY OF BIOLOGICAL AGENTS

Type of Micro

Organism

Disease (Category)

Transmission

(human to human)

Dissemination

Typical

Therapy

Vaccination

Symptoms

Delay of Symptoms (Days)

Duration of Illness

Mortality

Virus

Chikungunya Fever (non?lethal)

No

Vector/Aerosol

2?6

2 weeks

<1%

None

None

Incapacitating

joint and spine pains

Dengue Fever (non?lethal)

No

Vector/Aerosol

5?8

Days to weeks

< 1%

None

None yet

Fever, headaches,

muscle pain

Eastern Equine Encephalitis (lethal)

No

Vector/Aerosol

5?15

1?3 weeks

60%

None

None yet

Headache, fever,

vomiting,

bone pains

Tick borne Encephalitis (lethal)

No

Vector/Contact/ Droplets

7?14

1 week to months

Up to 30%

None

Available

Headache, fever,

vomiting,

delirium, coma,

paralysis

Japanese Encephalitis (lethal)

No

Vector/Airborne/ droplets

2?3

1 week

25%

None

Not good

Headache, fever, stupor, delirium,

coma

Rift Valley Fever (non?lethal)

No

Direct/Aerosol

4?6

1?2 weeks

Low

None

Experimental

Fever, malaise, muscular pain,

vomiting

Influenza (a)

(nonlethal)

Moderate

Aerosol

1?3

3?10 days

Low

None

Available

Well known

Yellow Fever (lethal)

No

Vector/Aerosol

3?6

1?2 weeks

<40%

None

Available

General aches,

prostration,

vomiting, epitasis,

jaundice

Small Pox

(lethal)

High

Aerosol/Vector/Direct

7-16

12-24 days

<35%

None

Available

Fever, malaise, aches,

pains, skin eruptions

Rickettsia

Q-Fever

(non-lethal)

No

Vector

10-21

1-3 weeks

<1%

Effective

None yet

Chills, fever,

headache, pains,

disorientation

Psittocosis

(non-lethal)

Rare

Aerosol

4-15

1 week plus

Low

Effective

None

Severe influenza

Symptoms

Rocky mountain Spotted Fever (non-lethal)

No

Vector/Aerosol

3-10

2 weeks to months

<80%

Effective

None yet

Chills, fever,

headache, muscle

pains, rash,

toxaemia

Epidemic

Typhus

(lethal)

No

Vector/ Aerosol

6-15

Weeks to months

<70%

Effective

Available

Chills, fevers,

headache,

muscle pains, rash

Bacteria

Pulmonary

Anthrax

(lethal)

No

Vector/ Aerosol

1-5

3-5 days

100%

Effective

Available

Malignant pustules are not

symptoms of pulmonary anthrax.

Symptoms are influenza like

Brucellosis

(non-lethal)

No

Direct/Aerosol

7-21

Weeks to years

2-6 %

Moderately effective

None yet

Variable, fever, depression,

exhaustion, aches

Cholera

(lethal)

High

Direct/Aerosol

1-5

1 or more weeks

<80%

Moderately effective

Available

Well known gastro-intestinal

Glanders

(lethal)

No

Direct/Aerosol

2-14

4-6 weeks

100%

Little

None

Ulcerated lesions, joint aches

Meliodiosis

(lethal)

No

Direct/Aerosol

1-5

4-20 days

100%

Moderately effective

None

Rapid glanders

Plague

Pneumonic/

Bubonic

(lethal)

High

Vector/

Man-man/

Aerosol

2-5

1-2 days

100%

Moderately effective

Available

Fever, shock, confusion,

swellings, delirium, coma

Tularaemia

(non-lethal)

No

Vector/Direct/

Aerosol

1-10

2 or more weeks

Low to 60%

Effective

Available

Swellings, fever, septicemia

Typhoid Fever

(non-lethal)

Moderate

Direct/Aerosol

7-21

Some weeks

>10%

Moderately effective

Available

Fever, abdominal distress,

rash, delirium

Dysentery

(non-lethal)

High

Vector/Aerosol

1-3

Days to weeks

Varies

Effective

None yet

Fever, aches, diarrhoea, toxaemia

Fungus

Coccidioidomycosis (non-lethal)

No

Aerosol

7-21

Weeks to months

Low

None

None

Influenza symptoms,

serious long term sequelae

 

Website by Creative Perspective