Ricin immunogenic in mice, rabbits, and humans. It has completed two successful clinical trials. Ricin has been involved in a number of incidents. In 1978, the Bulgarian dissident Georgi Markov was assassinated by Bulgarian secret police who surreptitiously shot him on a London street with a modified umbrella using compressed gas to fire a tiny pellet contaminated with ricin into his leg. He died in a hospital a few days later and his body was passed to a special poison branch of the British Ministry of Defence (MOD) that discovered the pellet during an autopsy. The prime suspects were the Bulgarian
Ricin is largely restricted to the gastrointestinal tract, where it may cause mucosal injuries. With appropriate treatment, most patients will make a decent recovery. Because the symptoms are caused by failure to make protein, they may take anywhere from hours to days to appear, depending on the route of exposure and the dose. When ingested, gastrointestinal symptoms can manifest within 6 hours; these symptoms do not always become apparent. Within 2 to 5 days of exposure to ricin, effects of ricin on the central nervous system, adrenal glands, kidneys, and liver appear. Ingestion of ricin causes pain, inflammation, and hemorrhage in