Ricin ingestion

Ricin would probably be aerosolized, but it could also be used by an assassin who might prepare it for ingestion or injection. Ricin is not nearly as potent as the C. botulinum toxin, and thus would have to be produced in very large quantities for large-scale use. 

Numerous laboratory studies in mammals have demonstrated that ricin and abrin are highly toxic and potentially fatal to animals and humans. Major symptoms of both ricin and abrin poisoning are dependent on the route of exposure, the dose (or number of beans) received, or the content of toxin in the seed (or age of seed). Upon ingestion, toxicity is dependent on the degree of mastication if the bean was... 

In oral administration of ricin in mice, the approximate LD50 dose is 20mg/kg with time to death up to 85 h (Fodstad et al, 1979). In a rat study, ricin was absorbed in the lymphatic blood vessels and largely distributed in the spleen and liver within 2 h of ingestion (Ishiguro et al, 1983). The study also demonstrated that up to 72 h after ingestion, approximately 20-45% of ricin is excreted in the feces (Ishiguro et al, 1992). 

Differential diagnosis of ricin exposure shows early inhalational ricin poisoning and will have primarily respiratory signs and symptoms, whereas ingested ricin will probably present early with gastrointestinal symptoms. 

ECG abnormalities in children who ingested castor beans have been noted by Kaszas and Papp (1960). These include QT interval lengthening, repolarization changes, and intraventricular conduction disturbances. Crompton (1980) later reported on experiments on pigs that experienced hemorrhagic lesions and an abnormal ECG due to ricin. At the present time, no antidotes or effective therapy are available to counteract the effects of ricin. 

DOT CLASSIFICATION 9 Label None SAFETY PROFILE Deadly poison by ingestion in humans. The seeds contain the deadly poison ricin, a plant lectin (toxalbumin) which inhibits protein synthesis in the intestinal wall. Ingestion of the seeds can cause after a delay period of several hours nausea, vomiting, diarrhea, and intestinal dysfunction. There may be massive fluid and electrolyte loss. Ingestion of as few as 2 seeds could be fatal. A potent allergen. When heated to decomposition it emits toxic fumes of NOx. See also RICIN. 

Transdermal exposure to ricin is not serious, since it is not well absorbed through the skin. Oral exposure, for example by ingestion of castor beans, can cause severe gastroenteritis, gastrointestinal hemorrhage, and death due to circulatory collapse. Parenteral injection of ricin is rapidly fatal, as is aerosol exposure the lethal dose by these routes is 5-10 micrograms/kg (8). 

Human toxicity can occur if the seeds are ingested from the plants or ornaments made from the plants. If the hard outer coat remains intact, no toxicity will occur. However, if the outer coating is damaged, then ricin is released. 

Though ricin can be deadly, most exposures result in uncomfortable but limited gastroenteritis and minimal systemic toxicity. Gastrointestinal decontamination should be considered, depending on the time of ingestion. Symptomatic and supportive measures are the mainstay of treatment. There is no specific antidote for this toxin. 

Data on exposnre throngh ingestion are also limited. There are no reported cases of ingestion of pure ricin toxin. Nevertheless, the signs and symptoms of exposure to the pure toxin are probably similar to those following ingestion of masticated... 

Ricin is a potent protein cytotoxin, easily extracted from the beans of the castor plant (Ricinus communis), which is ubiquitous. When ingested, ricin causes severe GI symptoms followed by vascular collapse and death. Ricin is made up of two hemagglutinins and two toxins. The toxins, RCL III and RCU TV, are dimers with molecular masses of approximately... 

Animal Lethal Dose of Ingested Castor Seed (g/kg) Lethal Dose of Injected (i.m.) Ricin (p.g/kg) Lethal Dose of Injected (i.p. or i.v.) Ricin (pig/kg) Relative Resistance to Injected (s.c.) Ricin ... 

The susceptibility of different animal species to poisoning with castor seed has been shown to vary by as much as 100-fold (Table 17.2) (Hunt et al., 1918 Balint, 1974). It is unclear to what extent this reflects differences in the amount of actual toxin ingested owing to variations in seed content, digestive processes, or protective regurgitation, versus more subtle innate or biochemical mechanisms of resistance to ricin in some animals. 

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