Ricin is one of the most toxic naturally occurring substances
known it's though less toxic than botulism. A larger quantity of ricin would be required to cover an area
and achieve the same lethal quality. This feature may limit the
use of ricin as a tactical weapon; however, it can be used for
small-scale operations. Ricin's significance as a potential biological
warfare agent relates to its availability worldwide, its ease
of production, and extreme pulmonary toxicity when inhaled.
Ricin has been used as a natural pesticide. It comes from the
seeds of castorbean plants which are used to make castor oil,
though that's derived from pressing the beans and keeping the
ricin out.
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| Symptoms |
Onset of acute symptoms include fever, chest tightness, cough,
difficulty in breathing, nausea, and arthralgias 4 - 8 hours after
inhalational exposure, followed by severe respiratory distress
and death from hypoxemia in 36-72 hours. Profuse sweating several
hours later signal termination of most of the symptoms.
When eaten, ricin causes severe gastrointestinal symptoms followed
by vascular collapse and death.
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How does it spread?
Castor plant
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Ricin is not communicable person to person.
Transmission is by inhaling the organism during industrial operations
and also through ingestion of castor bean meal.
The primary threat in biowarfare would be by aerosol release.
This feature may limit the use of ricin as a tactical weapon;
however, it can be used for small-scale operations. The agent
may also be delivered through contamination of food and water
supplies.
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| Diagnosis |
Acute lung injury in large numbers of geographically clustered
patients suggests exposure to aerosolized ricin. The rapid time
course to severe symptoms and death would be unusual for infectious
agents. Serum and respiratory secretions should be submitted for
antigen detection (ELISA). Acute and convalescent sera provide
diagnosis after the fact. Nonspecific laboratory and radiographic findings include
leukocytosis and bilateral interstitial infiltrates.
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Treatment
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Supportive care including intensive care measures, such as oxygen,
tracheotomy and mechanical ventilation and positive end-expiratory
pressure may be required for respiratory disease.
Therapy is supportive and should include maintenance of intravascular
volume. Standard management for poison ingestion should be employed
if intoxication is by the oral route.
There is presently no antitoxin or specific therapeutic drugs
available for treatment.
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Vaccine
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None available, but vaccines are under development.
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Mortality
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No statistics available.
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Sources:
USAMRIID's Medical Management of Biological Casualties Handbood;
Fourth Edition February 2001; pages 9-10; http://usamriid.detrick.army.mil/education/bluebook/bluebook.pdf
Federation of American Scientists; http://www.fas.org/nuke/intro/bw/agent.htm
Virtual Naval Hospital: Treatment of Biological Warfare Agent
Casualties; http://www.vnh.org/FM8284/index.html
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