Ricin and Abrin as Possible Agents of Bioterror

Abstract

Plant toxins – ricin and abrin, obtained in a purified form from the beans of the castor bean and Abrus precatorius respectively, are considered by Western experts as potential damaging agents of a biological nature. The purpose of this work is to consider the danger of using ricin and abrin as agents of biological terrorism, as well as to assess the existing approaches and means for identifying these toxins, treating the intoxication caused by them, as well as the level of development of vaccine preparations. Both toxins have a similar molecular structure and mechanism of action. They consist of two subunits – A and B, resistant to high temperatures and extreme pH values. The mechanism of their damaging action is based on irreversible inhibition of the process of protein synthesis. The LD50 of ricin for humans, according to various sources, is 3 µg/kg for inhalation and intravenous intake, 22–25 µg/kg for enteral intake, and about 500 µg/kg for subcutaneous intake. Abrin is more toxic than ricin, with an LD50 for humans ranging from 0.1 µg/kg to 1 µg/kg depending on the route of entry. In case of enteral poisoning with ricin and abrin, the victims develop symptoms of gastroenteritis within a few hours: nausea, vomiting and pain in the abdominal cavity and chest, diarrhea. Bleeding from various parts of the gastrointestinal tract may be present. In future, general intoxication symptoms (headache, weakness, fever) and symptoms of multiple organ damage (acute renal failure and acute liver failure) develop. In the terminal stage, symptoms of vascular shock and vascular collapse are expressed. Death usually occurs on the third day or later. Cases of the use of ricin and abrin for criminal and terrorist purposes are described in the article. The main approaches and modern means of indication, means of treating ricin and abrine intoxication, as well as the state of development of vaccine preparations are shown. The given data show that the danger of these toxins as damaging agents is underestimated in Russia. It is necessary to develop diagnostic test systems that allow early detection of intoxication with plant toxins in the affected and the toxins themselves on environmental objects, as well as specific means for the treatment and prevention of acute poisoning with ricin and abrin.