Abrin ingestion

Abrin, a potent toxin, is extracted from the seeds of the rosary pea (Abrus precatorius). Due to its easy availability and preparation, this toxin is an attractive option for weap-onizing in poor countries, and thus has also been included in the Sch ule 1 of the CWC. The mechanism of action of abrin is very similar to that of ricin however, in mice, abrin is 75 times more toxic than that of ricin (0.04 pg/ kg for abrin is equivalent to 3pg/kg of ricin). Similar to ricin, inhalation of abrin is found to be more toxic than ingestion. However, abrin ingestion has reported to be toxic to the liver, unlike ricin. At the cellular level, abrin is a potent toxalbumin known to cause cell death by inhibiting protein synthesis (namely, type 2 ribosomal inhibitory protein). Further, abrin is also known to induce endothelial cell damage leading to an increase in cell permeability, fluid and protein leakage, and tissue edema. 

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... 

The mature bean is innocuous if the hard outer coat is intact. Any interruption in the integrity of the seed coat (e.g., chewing) or ingestion of the soft-coated immature bean may cause toxicity. The inner core contains the amino acid n-methyltryptophan, abric acid, glycyrrhizin, and abrin. Abrin is stable in the gastrointestinal tract where it is slowly, but erratically absorbed. In rats, distribution sites occur primarily in the liver (12%) and spleen. Biotransformation and elimination of toxalbumins are poorly defined. 

The human fatal dose of abrin via parenteral routes has been estimated to be approximately 0.1-1 JLg/kg based on case reports of accidental or intentional ingestion. No serious toxic effects were observed in terminal cancer patients treated with as much as approximately 0.3 p,g/kg (i.v.) abrin (Dickers et al., 2003). As with ricin, however, most documented cases of abrin poisoning in humans have involved chewing or swallowing A. precatorius (jequirity) seeds, a route of exposure that is much less dangerous and which predominantly causes GI toxicity (Gunsoulus, 1955 Hart, 1963 Davis, 1978 Fernando, 2001). 

You could ingest (swallow) abrin if it is in food or water. 

Effects of abrin poisoning depend on whether abrin was inhaled, ingested, or injected. 

Initial symptoms of abrin poisoning by inhalation may occur within 8 hours of exposure. Following ingestion of abrin, initial symptoms may occur in less than 6 hours but usually are delayed for 1 to 3 days. 

Ingestion If someone swallows a significant amount of abrin, he or she would develop vomiting and diarrhea that may become bloody. Severe dehydration may be the re.sult, followed by low blood pressure. Other signs or symptoms may include hallucinations, seizures, and blood in the urine. Within several days, the person s liver, spleen, and kidneys might stop working, and the person could die. 

Death from abrin poisoning could take place within 36 to 72 hours of exposure, depending on the route of expo.sure (inhalation, ingestion, or injection) and the dose received. If death has not occurred in 3 to 5 days, the victim usually recovers. 

Ricin is most toxic when inhaled and is therefore a potential aerosol threat. However, large quantities would he needed to cause toxicity. Ricin is much less lethal when ingested, suggesting poor absorption. The toxicity and lethality of parenteral exposure to ricin are well documented. Abrin which is closely related to ricin in structure is extremely toxic with an LD50 dose for humans of 2 pg/kg. 

Abrin is poisonous if inhaled, injected or ingested. Seeds of the rosary pea used to make beaded jewellery may be chewed or swallowed which could lead to poisoning. 

Symptoms are secondary to the inhibition of protein synthesis and cell death. Death is usually due to multi-organ failure. Ingested in larger doses, abrin causes severe diarrhoea and victims can die of subsequent shock. The symptoms of abrin exposure are the much the same as ricin, and are summarised in Table 5.25 (p. 314). 

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