Ricin

1
Ricin
2
Toxin

• Castor plant - Ricinus communis
• From processing waste
• Castor beans for oil
• Very stable
• In several forms
• Powder, mist, pellet,
  dissolved in water or weak acid
• Irreversibly blocks protein synthesis
• Potential medical uses

3
History
4
History

• World War I
• Considered for use as weapon by US
• 1978 London
• Assassination of Bulgarian exile, Georgi
  Markov
• 1991 Minnesota
• Patriots Council plot to kill US Marshal

5
History

• Iran-Iraq war
• Reports of ricin use
• Found in Al Qaeda caves in Afghanistan
• 2003
• Ricin found in London apartment
• 2004
• Toxin found in Senators office
• Found in letter source unknown

6
Transmission
7
Transmission

• Three routes
• Inhalation
• Ingestion
• Injection
• Person-to-person transmission
  does not occur

8
Human Disease
9
Signs and Symptoms

• Inhalation
• Incubation less than 8 hours
• Ingestion
• Incubation few hours to few days
• Injection
• Incubation immediate to hours

10
Clinical Symptoms

• Inhalation
• Cough, weakness, fever, nausea, muscle aches,
  chest pain and cyanosis
• Pulmonary edema, 18-24 hours after inhalation
• Severe respiratory distress
• Death from hypoxemia, 36-72 hours

11
Clinical Symptoms

• Ingestion
• Least toxic form
• Less toxic if castor beans swallowed whole
• Severe GI symptoms, 1-2 hours
• Rapid heartbeat
• Internal bleeding
• Vascular collapse
• Death occurs in 3 days or more

12
Clinical Symptoms

• Injection
• Local pain and necrosis at site of injection
• Systemic signs similar to those of ingestion

13
Diagnosis

• Based on clinical symptoms
• ELISA
• Serum or respiratory secretions
• Immunohistochemistry
• Tissues
• Serology for retrospective diagnosis
• Ricin is very immunogenic

14
Treatment

• No treatment, vaccine or antisera currently
  available
• Supportive care
• Dependent on route of exposure
• Ventilator
• Gastric lavage or cathartics

15
Animals and Ricin
16
Animals Affected

• Affects all domestic animals
• Horses most susceptible
• Lethal dose 0.01 of body weight in seeds
• Chickens, ducks and frogs somewhat insensitive
  to toxin

17
Clinical Signs

• Inhalation
• Pulmonary edema
• Respiratory distress
• Death 36-72 hours

18
Clinical Signs

• Ingestion
• Most common route
• Initial clinical signs
• Frequent and violent vomiting, diarrhea,
  depression, weakness and
  shortness of breath
• Salivation, trembling and incordination
• Some affected animals may recover
• With or without treatment

19
Diagnosis and Treatment

• Diagnosis and treatment in animals similar to
  humans
• Experimental vaccines and antitoxins promising
  but not yet available

20
Control and Protection

• Research on vaccines and antisera
• Decontaminate exposed skin
• Soap and water and/or
• 0.1 sodium hypochlorite (bleach)
• Protective mask
• Effective against aerosol exposure
• Standard precautions
• Should be used by healthcare workers

21
Ricin as a Biological Weapon

• Extreme ease of production
• Widely available
• Relatively high toxicity
• Currently no treatment
• Supportive care only

22
Acknowledgments
Development of this presentation was funded by a
grant from the Centers for Disease Control and
Prevention to the Center for Food Security and
Public Health at Iowa State University.
23
Acknowledgments
Author Co-author Reviewer
Jamie Snow, DVM, MPH Radford Davis, DVM,
MPH Jean Gladon, BS