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Possible Ricin Attacks in the US

Image of Capital Bldg. Washington, DC
Matthew Watson, Senior Analyst
Date posted:
April 17, 2013
Publication type:

Our Perspective: Ricin, April 2013


On Tuesday, April 16, 2013, major news outlets reported that an envelope containing a white granular powder, preliminarily identified as a preparation of ricin toxin, was intercepted at a mail sorting facility used by Congress. The envelope was addressed to Senator Roger Wicker. On Wednesday, April, 17, an additional letter containing a powder initially identified as ricin and addressed to President Obama was identified at a separate mail sorting facility used by the White House. Additional suspicious letters addressed to other members of Congress are currently being investigated.

In compliance with interagency guidance, initial testing took place in both the mail facilities and in an unnamed laboratory in Maryland. Confirmatory testing is now being performed by the FBI and at Fort Detrick, and results should be available within the next 24-48 hours.  At the time this report is being written, no cases of illness have been reported.

About Ricin Toxin: Ricin is a toxin derived from the beans of the castor plant, Ricinus communis. Ricin acts by inhibiting protein synthesis. As ricin is a toxin, and not a pathogen, person-to-person spread is not possible.

The symptoms and toxicity of ricin depend on the dose, method of preparation, and route of exposure—inhalation, ingestion or injection. Inhalation is the most lethal route of exposure, and the letters contained a powder presumably intended for inhalation.

Within a few hours of inhaling a sufficiently sized dose of aerosolized ricin, patients could experience difficulty breathing, coughing, and tightness in the chest, with heavy sweating, fever, and nausea. Low blood pressure and respiratory failure can occur.  In the most serious cases, the results can be fatal. Anyone with symptoms who may have been exposed to ricin should seek immediate medical attention. (For more information on the use of ricin as a biological weapon, consult the Center for Biosecurity’s .)

Medical Countermeasures: There is currently no approved vaccine or therapeutic agent available to prevent or treat ricin intoxication. Care of exposed patients is supportive. Research on experimental vaccines is ongoing, but those products are not yet available for use.

Implications: There is a long history of use of ricin for bio-crimes and occasionally for terrorism, but, with the exception of one victim of assassination, no one has died from ricin attacks. Although it is believed that ricin may be an agent of choice because it is easy to obtain the castor beans from which it is made and it is simple to prepare, it has proven to be a very ineffective weapon. Nonetheless, if a person was exposed to a sufficient dose, the medical consequences could be quite severe.

This evolving event speaks to the importance of rapid identification of suspicious mail, rapid confirmatory testing of their contents, medical monitoring of staff who may have been exposed, and decontamination efforts should they become necessary. We will follow these events closely and report regularly as appropriate.



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