Ricin chain A. This vaccination is effective for several months due to the body's production of antibodies to the foreign protein. In 1978 Bulgarian defector Vladimir Kostov survived a ricin attack similar to the one on Georgi Markov, probably due to his body's production of antibodies. When a ricin-laced pellet was removed from the small of his back it was found that some of the original wax coating was still attached. For this reason only small amounts of ricin had leaked out of the pellet, producing some symptoms but allowing his body to develop immunity to further poisoning. The seeds of
Assassination assassinated by ricin poisoning. A tiny pellet containing the poison was injected into his leg through a specially designed umbrella. Widespread allegations involving the Bulgarian government and KGB have not led to any legal results. However, after the fall of the USSR, it was learned that the KGB had developed an umbrella that could inject ricin pellets into a victim, and two former KGB agents who defected said the agency assisted in the murder. The CIA made several attempts to assassinate Fidel Castro, many of the schemes involving poisoning his cigars. In the late 1950s, KGB assassin Bohdan Stashynsky killed