Biological Weapons --
Ricin



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.


How does it spread?


Castor plant



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.


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.

Treatment
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.

Vaccine
None available, but vaccines are under development.

Mortality
No statistics available.

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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