Ricin toxin inhalation

Funatsu, G., Funatsu, M. (1970). Isolation and chemical properties of various types of ricin. Jpn. J. Med. Sci. Biol. 23 342-4 Gareth, D., Griffiths, G.D., Rice, P., Allenby, A.C., Bailey, S.C., Upshall, D.G. (1995). Inhalation toxicology and histopa-thology of ricin and abrin toxins. Inhal. Toxicol. 7 269-88 Gill, D.M. (1982). Bacterial toxins a table of lethal amounts. Microbiol. Rev. 46 86-94. 

Griffiths, D., Rice, P., Allenby, A.C., Bailey, S.C. and Upshall, D.G. (1995a) Inhalation toxicology and histopathology of ricin and abrin toxins. Inhal Toxicol, 7, 269-288. 

The initial symptoms associated with inhalation of ricin toxin are cough, weakness, fever, nausea, muscle aches, chest pain, and cyanosis. Pulmmiaiy edema occurs about 18-24 h after inhalation, and severe respiratory distress and death from hypoxemia ensues at 36-72 h. 

It is is the third most toxic substance known after plutonium and botulism it is a protein toxin that is extracted from the castor bean (Ricinus communis). The USA Centers for Disease Control (CDC) considers 500 pg to be the lethal dose of ricin in humans if exposure is from injection or inhalation. Ricin is poisonous if inhaled, injected, or ingested, acting by the inhibition of protein synthesis. While there is no known antidote, the US military has developed a vaccine. 

A. Characteristics. Ricin is a glycoprotein toxin from the seed of the castor bean plant. Altering ribosomal RNA blocks protein synthesis, thereby killing infected cells. Ricin s significance as a potential biological warfare agent relates to its availability worldwide, ease of production, and extreme pulmonary toxicity when inhaled. 

Ricin is more toxic by inhalation than by ingestion. The symptoms from inhaling aerosolized ricin are weakness, fever, cough and pulmonary edema. Such effects may onset after a latent period of 8 hours. Death can result in 36 to 72 hours from severe respiratory distress. The toxin binds... 

Ricin is a large, moderately toxic, protein dichain toxin from the bean of the castor plant, Ricinis communis. It can be produced easily in relatively large quantities. Ricin was developed as a biological weapon by the United States and its allies during World War II. Although ricin is toxic by several routes, when inhaled as a respirable aerosol, it causes severe necrosis of the airways and increased permeability of the alveolar-capillary membrane. The inhalational route... 

Ricin is not an infectious agent but rather is a potent protein toxin produced from castor beans (Figure 3.5). Castor beans are common worldwide and the toxin is easy to produce. It makes a good bioweapon (better for assassination than for mass exposure) because it is stable and can be administered by several routes (inhalation, oral, or injection). Although ricin is not as deadly as some toxins, the ease of its production makes it attractive as a weapon. It has been especially attractive for small terrorist organizations that lack funds for obtaining more deadly weapons. Aerosol would be the most effective delivery method, but it is difficult to produce ricin particles in the 5-micron range so it is less useful for mass exposures. 

Three routes of ricin exposure are known to exist for humans and animals inhalation, natural infection by ingestion, and injection. Depending on the route of exposure (such as injection), as little as 500 pg of ricin could be enough to kiU an adult. A 500-pg dose of ricin would be about the size of the head of a pin. A much greater amount would be required to kill a human being by either the inhalation or ingestion routes. Toxins are not usually transmitted person-to-person or animal-to-animal. Secondary aerosolization is not thought to be of concern. 

The incubation period for ricin is dependent on the route of transmission. If the toxin is inhaled, the incubation is about 8 h. The incubation period for ingestimi is a few hours to days. If ricin is injected under the skin, the incubation period could be immediate to several hours, depending on the location of injection and the dose of toxin injected. 

There is no treatment or vaccine currently available for ricin poisoning. Supportive care is recommended based on the route of exposure, and includes respiratory support for inhalational exposure, gastric washing (cleaning), and cathartics to remove the toxin from the GI tract if ingestirMi has occurred. 

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. 

The toxins ricin and abrin cause widespread damage to DNA in the body leading to multiple organ failure. Until recentiy, it was thought that they could only be introduced into the body by an injection, but there are indications that they could be active by inhalation of an aerosol. Ricin can be extracted from castor oil plants and there have been reported attempts to do this by terrorist cells. Ricin is highly toxic and was used in the assassination of the Bulgarian diplomat Georgi Markov in London in 1978. At present, there is no specific antidote for toxic trauma caused by ricin. 

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