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Botulism

What is botulism?

Botulism is a rare disease caused by a toxin produced by the spore-forming bacterium Clostridium botulinum. C. botulinum occurs naturally and can be found in soil, water, animals, contaminated food or agricultural products. The toxin produced by C. botulinum is the most potent toxin known and can affect humans, animals, even fish.

There are three kinds of botulism that occur naturally: foodborne, wound and infant botulism.

  • Foodborne - rare, potentially life-threatening, caused by eating food contaminated with botulinum toxin.
  • Wound - unusual, rare. Occurs when an open wound becomes contaminated with the bacteria which produce the toxin which is then released into the bloodstream.
  • Infant botulism - typically in children less than a year old, as a result of eating bacterial spores and results in toxin in the intestines.

One form of human-made botulism is contracted through inhalation.

  • Inhalational botulism is the only known human-made form. It has been known to be transmitted from monkeys to veterinarians and lab workers.

How is botulism spread?

Generally through contaminated food containing the botulinum toxin.

Is botulism spread from person to person?

No. Botulism cannot be transmitted from person to person.

How can botulism be prevented?

Foodborne botulism is caused by improper home canning of low acid foods, such as asparagus, green beans, beets, corn and fish or meat. Botulism from other sources has included improperly stored garlic in oil, chili peppers and tomatoes. It is essential to follow strict hygienic procedures to reduce contamination of foods. Oils infused with garlic or herbs should be kept refrigerated.

Honey should not be given to children under one year of age. Bees may pick up the botulism spores from flowers or soil and the spores are not destroyed in the processing of honey. After the age of one, children's intestinal bacteria successfully prevent growth of C. botulinum.

What are the symptoms?

The symptoms vary according to the type of botulism and the degree of exposure to the toxin. They will generally appear anywhere from 6 hours to 36 hours for foodborne botulism; up to 72 hours for inhalational; and from 4 to 8 days for infection of a wound.

Early symptoms for all forms include double or blurred vision, difficulty speaking and swallowing, dry mouth and fatigue. Nerve damage results in acute paralysis which affects the face, head, throat, chest and extremities. Death can result from respiratory failure.

How is botulism treated?

Botulism must be diagnosed and treated quickly with an antitoxin which cannot reverse the effects of the disease but can prevent further paralysis. Antibiotics are not effective against toxins. Treatment is limited to supportive therapy and antibiotics to treat secondary bacterial infections.

Is there a vaccine to prevent infection from the botulism toxin?

Not for the general public. Laboratory employees who work with the toxin or botulism organisms are more likely to be exposed to the risk of toxin. These people may be vaccinated because of the risk of exposure.