May 29, 2016
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Botulism (cont.)

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What causes botulism?

Neurotoxin, synthesized and secreted by Clostridium botulinum bacteria (and a few other Clostridium species), cause botulism. The toxin causes the disease by blocking the release of acetylcholine from motor nerve endings. This result produces the symptoms associated with botulism.

How many kinds of botulism are there?

There are three main kinds of botulism, which are categorized by the way in which the disease is acquired:

  • Food-borne botulism is caused by eating foods that contain the botulinum neurotoxin. Recent small outbreaks have occurred in Canada due to fermented fish and in New York due to unrefrigerated bulk tofu contamination.
  • Wound botulism is caused by neurotoxin produced within a wound that is infected with the bacteria Clostridium botulinum.
  • Infant botulism occurs when an infant consumes the spores of the botulinum bacteria. The bacteria then grow in the intestines and release the neurotoxin.

Three other kinds of botulism have been described but are seen rarely. The first is adult intestinal colonization that is seen in older children and adults with abnormal gastrointestinal tracts. Only rarely does intestinal infection with Clostridium botulinum occur in adults because the adult GI tract inactivates ingested Clostridium botulinum bacteria through gastric acid and enzymatic activity. Typically, the adult form of this intestinal botulism is related to abdominal surgical procedures that interfere with such inactivation mechanisms. The second kind (injection botulism) is seen in patients injected with inappropriately high amounts of therapeutic neurotoxin (for example, Botox, Dysport, Myobloc), while the third kind (inhalation botulism) has occurred in laboratory personnel who work with the neurotoxins. All six kinds of botulism are potentially fatal.

How serious is botulism?

Botulinum neurotoxin is considered one of the most potent, lethal substances known. As little as about 1 nanogram/kg can be lethal to an individual, and scientists have estimated that about 1 gram could potentially kill 1 million people. This small amount of toxin capable of killing humans has made the toxin a candidate for use in weapons for biowarfare and bioterrorism. All forms of botulism can be fatal and are considered medical emergencies. Food-borne botulism can be especially dangerous because many people can be poisoned by eating even small amounts of neurotoxin-contaminated food. A botulism outbreak is a public-health emergency that is reportable to the U.S. government.

Medically Reviewed by a Doctor on 11/16/2015


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