By Kristina Fiore, Staff Writer, MedPage Today It may have been a preferred tool of Soviet hit men, but ricin generally flops as a weapon of mass destruction, several bioterrorism experts told MedPage Today.
The toxin, which is derived from castor beans, is most deadly when inhaled or injected, but there are several challenges to spreading it widely enough to inflict damage.
"Ricin for a while was considered to be a weapon of mass destruction (WMD), but the current thinking is that it's hard to disseminate over large populations and it's not contagious person-to-person," said Robert Emery, DrPH, of the University of Texas Health Science Center at Houston.
The poison is the focus of national attention because ricin-laced letters were sent to President Barack Obama and at least one U.S. Senator just days after a bombing at the Boston Marathon.
But even just a small amount can be highly toxic, especially if inhaled or injected, Emery said, and there is no antidote. Breathing in a dose of 240 to 400 mcg can be lethal, and it takes less than that to do major damage if injected.
Bulgarian dissident Georgi Markov, a BBC journalist and critic of the Bulgarian regime who had defected to England, learned that the hard way in 1978 when a suspected KGB agent poked him with an umbrella laden with an injection of ricin.
Markov was dead within 3 days. "It’s more effectively used against an individual target,” Steven Marcus, MD, professor of preventive medicine and community health at New Jersey Medical School, told MedPage Today.
Experts cite this as the lone confirmed fatal case of ricin poisoning, and of other attempts to use ricin as an agent of terror, none have died and few have even become sick, according to Eric Toner, MD, of the Center for Biosecurity at the University of Pittsburgh Medical Center.
That may have something to do with the quality of the product, Toner said. Even though it can be made in a kitchen -- Emery said it is known as the "poor man's toxin" -- by cooking castor beans and using a solvent to extract the ricin, it's not necessarily pure or concentrated.
"It's not usually like what was used against Markhov, which was produced by a sophisticated government lab and very different from being home-brewed," Toner told MedPage Today.
Experts say ricin is less lethal if ingested, but it can still cause damage, and eating enough castor beans can make patients sick -- usually with terrible bouts of diarrhea -- or kill them.
Castor oil used to be one of the most common laxatives, Toner noted, even though it doesn't contain any significant amount of ricin.
Few of the experts contacted by MedPage Today were concerned about cutaneous exposure, which would be the likeliest form among those working in Washington mailrooms. Toner said the powdery substance probably wouldn't have been potent enough to do any damage had it made contact with skin.
"I suspect the perpetrators know that," he said. "It's a very effective way to draw attention and cause havoc, but a very ineffective way to kill someone."
It can't compare to a real WMD like anthrax, he noted, which is easier to disperse and far more fatal.
Ricin blocks protein synthesis at the cellular level and can wreak havoc on nearly all organs. Symptoms manifest anywhere from 4 to 24 hours after exposure, and vary via route of exposure. Those who have inhaled it usually have difficulty breathing, cough, tightness in the chest, and fever.
Because there is no antidote, clinicians can only provide best supportive care while waiting for the toxin to clear, according to Lewis Nelson, MD, an emergency physician at NYU Langone Medical Center. That includes IV fluids as well as mechanical ventilation and renal support if needed.
Though wide dissemination remains a challenge, Nelson said major metropolitan areas like New York would be about as prepared for a ricin attack as they would be for a pandemic flu.
"If you looked at someone with ricin poisoning, you couldn't distinguish it from a major infection," he said. "You just have to try to keep the patient alive until the toxin clears and the organs recover."
With the exception of those who specialize in emergency medicine, doctors receive little training in not only treatment of ricin poisoning, but bioterrorism in general, according to Ken Spaeth, MD, MPH, director of occupational and environmental medicine at North Shore Long Island Jewish Health System on Long Island.
"Relatively little is taught about ricin and ... other biological weapons such as anthrax and smallpox," Spaeth told MedPage Today. "Education regarding chemical and radiological weapons is even more deficient."
He added that recent surveys show most physicians feel unprepared to care for patients exposed to biological, chemical, or radiological weapons.
But Toner noted that information from the CDC on bioterrorism and how to manage these situations is easily available online.
Emery also noted that the U.S. appears to be interested in trying to develop a preventive ricin vaccine, even though attempts at an antidote have failed.
It's not clear whether the ricin-laced letters were connected to the Boston Marathon bombing, but Toner pointed out that since the first letter was received yesterday -- only a day after the bombing -- it's likely the letters were in the mail before the bombs were placed.
"It's either a coincidence, part of a larger plan, or someone has much better mail service than I do," he joked.
UPDATE: This article, originally published on April 17, 2013 at 5:58 p.m., was updated with new material on April 18, 2013 at 1:27 p.m. 
Kristina Fiore
Staff Writer
Kristina Fiore joined MedPage Today after earning a degree in science, health, and environmental reporting from NYU. She's had bylines in newspapers and trade and consumer magazines including Newsday, ABC News, New Jersey Monthly, and Earth Magazine. At MedPage Today, she reports with a focus on diabetes, nutrition, and addiction medicine.
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