Canis ISSN: 2398-2942

Clostridium botulinum

Synonym(s): C. botulinum

Contributor(s): David Bemis, Melissa Kennedy




  • Genus: Clostridium.
  • Family: Clostridiaceae.
  • Species: botulinum.


  • Gk: kloster - spindle.
  • L: botulus - sausage.

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Clinical Effects



  • Types A, B and G found in soil. Types C, D, E and F found in muddy soils and aquatic sediments.
  • Types C and D also inhabit intestinal tract of various animals.
  • Animal and plant material may be contaminated from these sources.
  • Endospores germinate in intestines and tissues upon death of animals.


  • C. botulinum does not normally invade animal tissues.
  • Endospores germinate in carcasses and rotting vegetation.
  • Vegetative cells reproduce and synthesize neurotoxin.


  • Exogenous or endogenous.
  • Ingestion of preformed toxin from carcasses or rotting vegetation in contaminated food or water is most common source.
  • Ingestion of endospores and wound contamination also occur.

Pathological effects

  • Resistance depends on circulating antitoxin specific for the type of toxin.
  • Botulism is usually caused by ingestion of the preformed neurotoxin and is an intoxication rather than an infection.
  • May be caused by wounds being contaminated by endospores which germinate; the neurotoxin is formed at the site of infection.
  • Rarely, the endospores germinate in the intestine in human infants, broiler chickens, turkey poults and foals.
  • The toxin is carried by the blood to the peripheral nerve cells where it prevents release of acetylcholine → flaccid/respiratory paralysis → death.
  • Generalized lower motor neuron disease and parasympathetic dysfunction; cranial nerves as well as peripheral nerves may be affected.
  • Non-toxigenic C. botulinum strains may occur in mixed anaerobic infections.
  • Toxins C1 and D are genetically encoded by bacteriophage.

Other Host Effects

  • Endospores may be found in the intestines of normal animals.
  • Endospores are distributed in soil and aquatic environments.


Control via animal

  • If recent ingestion suspected, evacuate stomach and purge.
  • Antitoxin treatment, if available, may be helpful.
  • Symptomatic therapy is most important, including respiratory support if necessary.

Control via chemotherapies

  • Supportive care.
  • Early antitoxin treatment with specific or polyvalent antitoxin may be beneficial.
  • Test intradermal (0.1 ml) approximately 20 min prior to administration for warning of allergic reaction.

Control via environment

  • Avoid contamination of feedstuffs, especially with animal tissues, eg rodents.


  • Toxoid vaccines have been used in waterfowl adn mink.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • van Nes J J, van der Most van Spijk D (1986) Electrophysiological evidence of peripheral nerve dysfunction in six dogs with botulism type C. Res Vet Sci 40 (3), 372-376 PubMed.