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
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.
MEDICAL AND COSMETIC USES
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.
BIOCHEMICAL WARFARE
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.
