Inhalational botulism toxicity

Botulinum toxin is on the A list of potential bioterrorist weapons because of its toxicity, its lethality, its ease of production, ease of transport, ease of use, and the need for prolonged, intensive care of affected victims (36). The colorless, odorless, and probably tasteless toxin is the most poisonous substance known (36). The most efficient route of exposure through a terrorist attack would be inhalational, causing a distribution of illness distinctly different from naturally occurring human botulism. One gram of crystalline toxin dispersed through an airborne route, could kill up to 1 million people, although technical limitations on dispersal could reduce the number of casualties (36). 

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. 

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