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Clostridium botulinum is a Gram-positive, sporulating, obligate anaerobe, found in soil, lake and pond sediments and in the intestinal tracts and faeces of animals. It is clinically notorious for producing a potent neurotoxin, the causative agent of Botulism. But more recently its toxicity has been exploited in medicine and as a potential bio weapon.


Botulism is a rare, but serious paralytic illness caused by the
botulinum neurotoxin. With a lethal dose of one microgram, it is one of the most powerful naturally occurring toxins known. The toxin is specific for peripheral nerve endings at the point where a motor neurone stimulates a muscle. It binds to the neurone preventing the release of acetylcholine across the synaptic cleft. The result is respiratory and musculoskeletal paralysis without treatment, death. Effective treatment involves of antitoxin administration and artificial respiration.

There are three main kinds of botulism:

  • Foodborne botulism: caused by eating food that contains the botulinum toxin. The name "sausage poison", or "Canadian bacon pathogen" is well earned as this bacterium often causes poisoning by growing in badly prepared meat products.
  • Infant botulism is caused by consuming bacterial spores, which then grow in the intestines and release toxin. It is rare, but mostly linked to consumption of honey.
  • Wound botulism is caused by toxins produced from a wound infected with Clostridium botulinum.. This is the rarest type of botulism, but has recently increased in the USA due to spiraling drug injection.
Cases of Botulism are very rare. In the United States an average of 110 cases of botulism are reported each year and in the EU, an average of 73.


Researchers in the 1950s discovered that injecting overactive muscles with minute quantities of botulinum decreased their activity for a period of 4 to 6 months. Therapeutic and more recently cosmetic applications of these findings soon followed. Botulinum toxin is now sold commercially under the brand names Botox and Dysport for treating:
  • crossed eyes (Strabismus)
  • migraine headaches
  • cervical dystonia (a neuromuscular disorder involving the head and neck)
  • blepharospasm (Uncontrollable blinking)
  • severe primary axillary hyperhidrosis (excessive sweating)
  • Softening frown lines between the eyebrows.


Botulinum toxin poses a major bioweapon threat because of its extreme lethality and ease of production. There are however, no documented cases of the toxin actually being used in warfare. It may have been used in the Operation Anthropoid to kill top Nazi Reinhard Heydrich and in "Operation Mongoose", where in 1961, the CIA are believed to have saturated Fidel Castro's cigars with botulinum toxin in a possible assassination attempt.

Concerns over the use of botulinum toxin as a terrorist weapon, may also be unfounded, as commercially available vials contain only an extremely small fraction of the lethal dose and its anaerobic origin makes home-growing very difficult.