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Profiles for Health Care Workers (Fact Sheets) - "B" Agents

  • Health Care Providers: If you suspect a patient has been exposed to a biological or chemical agent please call the Office of Infectious Disease Services at (602) 364-4562
    On-call staff are available 24 hours a day, 7 days a week.

Ricin toxin

Causative Agent:
Potent protein toxin derived from Ricinis communis, the castor bean plant

Route of Exposure:
Inhalation (the most likely form for bioterrorism) or ingestion

Toxic Dose: The LD50 of inhaled ricin is 3-5 mg/Kg. Incubation Period: The incubation period for symptoms due to oral ingestion is usually less than 6 hours, although symptoms have been reported as quickly as 15 minutes.

Clinical Effects:
If the toxin is ingested, there is a rapid onset of nausea, vomiting, abdominal cramping, fever, and severe diarrhea with vascular collapse. Death generally occurs as soon as the third day. The consequences of human inhalation of ricin toxin is not known. However, in animal models, respiratory distress occurs with airway inflammation, pneumonia, and pulmonary edema. Death usually occurs from 36-72 hours after exposure.

The mortality rate due to ricin ingestion is 2-6%. The human mortality rate from inhalational ricin is unknown. Careful attention to fluid and electrolyte balance should lessen mortality. Transmissibility: Ricin intoxication cannot be transmitted from person to person.

Primary Contamination & Methods of Dissemination:
Methods of dissemination due to bioterroism could be via aerosolization or sabotage of the food or water supply.

Secondary Contamination & Persistence of Organism:
Ricin is not volatile. Risk to health care workers from secondary aerosols would be unlikely.

Decontamination & Isolation:

  • Patients - Only standard isolation precautions are needed. Skin decontamination can be done with soap and water or a 0.5% hypochlorite solution (one part household bleach & nine parts water = 0.5% hypochlorite solution).
  • Equipment, clothing & other objects - Surface cleansing can be done with a 0.5% hypochlorite solution.

Laboratory Testing:
Ricin can be detected in environmental samples by a fluorescence immunoassay or PCR available at the State Health Lab. Ricin testing in body fluids is experimental, but ricin may be able to be detected in body fluids such as emesis, stools, serum, or on nasopharyngeal swabs.

Therapeutic Treatment:
Treatment is supportive. Treatment for inhalational ricin should include management for pulmonary edema. If a patient has ingested ricin, gastric lavage with activated charcoal followed by catharsis with magnesium citrate is recommended. It is also important to replace volume due to GI fluid losses, and to be meticulous in fluid and electrolyte management. Ricin is not dialyzable.

Prophylactic Treatment:
There is no known prophylaxis for humans. A vaccine is under development.

Differential Diagnosis:
Enteric pathogens can cause fever and gastrointestinal involvement, but vascular collapse would be unusual.

Respiratory symptoms can occur with respiratory infections, Q fever pneumonia, plague pneumonia, tularemia pneumonia, toxin inhalation (such as staphylococcal enterotoxin B or trichothecene mycotoxins), and chemical warfare agents such as phosgene.

Aerosolized ricin is distinguished from routine infections by progressive respiratory symptoms in spite of antibiotics, no widened mediastinum (as in anthrax), progressive worsening (respiratory effects of staphylococcal enterotoxin B tend to stabilize rapidly), fewer systemic effects than trichothecene mycotoxins, and a slower progression in symptoms than phosgene exposure.


  • Kortepeter M, Christopher G, Cieslak T, et al. Medical Management of Biological Casualties Handbook. U.S. Army Medical Research Institute of Infectious Diseases, U.S. Department of Defense; 2001: 70-73 Franz DR, Jaax NK. Ricin Toxin. In: Zajtchuk R, Bellamy RF, eds. Medical Aspects of Chemical and Biological Warfare. Washington, DC: Office of the Surgeon General, U.S. Department of the Army; 1997: 631-642.
  • National Institute for Occupational Safety and Health. NIOSH Emergency Response Card. Centers for Disease Control and Prevention; 2004
  • Wortman G. Ricin Toxin. In: Roy MJ, ed. Physician’s Guide to Terrorist Attack. Totowa, NJ: Humana Press, Inc.; 2004:175-179

Find the PDF version of this Fact Sheet in the Zebra Manual.