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Germs that infect humans

Clostridium botulinum

Clostridium botulinum

© Dennis Kunkel Microscopy, Inc.

Microorganism: the bacillus Clostridium botulinum, serotypes A and G.

Disease: botulism (food poisoning)

Occurrence of the disease

Current situation: in 1999, fewer than 15 cases were reported in Canada.

Mechanism of action of the microorganism: C. botulinum is capable of forming spores, which are a very resistant form of the bacterium. When the bacteria or the spores enter the body, often through contaminated food or through a wound a toxin (a poison) produced by the bacteria proceeds to the nervous system, where it blocks a specific molecule known as acetylcholine. This molecule is responsible for the transmission of messages between nerve cells. In blocking acetylcholine, the disease interferes with the transmission of messages in the nervous system, which eventually will cause paralysis.

Symptoms of the disease: disturbed vision, difficulty in swallowing and speaking, muscular weakness, nausea, and vomiting.

Incubation period: 12 to 36 hours

Contagious period: the disease is generally not spread from person to person.

Hosts: spores of the bacterium C. botulinum are found in soil around the world.

Transmission: infection generally occurs when food is not heated sufficiently during the canning process to kill the spores of C. botulinum.

Discoverer of the microorganism: Van Ermengem in 1896.

Treatment: intravenous antitoxin administered as quickly as possible.

Geographical distribution of the microorganism: worldwide

Prevention: strict adherence to safety regulations in the food industry, and education of the public concerning safe methods of home canning. Honey should not be given to infants before one year of age. Avoid using the contents of cans that appear swollen, or that have a bad odor. A person who suspects that he or she has eaten contaminated food should go immediately to a hospital for stomach pumping.

Vaccine: not available.