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
Wood Green ricin plot incident; they all survived. All other suspects were either released without charge, acquitted, or had their trials abandoned. Physicians throughout the United Kingdom were warned to watch for signs that patients had been poisoned by ricin, and the public health director for London urged the public not to be alarmed following some media reports. Britain's largest circulation tabloid newspaper, "The Sun", reported the discovery of a "factory of death", and other newspapers warned on their front pages "250,000 of us could have died", "Poison gang on the loose" and "Killer with no antidote". The fact that no ricin had been