Felis ISSN 2398-2950

Clostridium botulinum

Synonym(s): C. botulinum

Contributor(s): David Bemis, Melissa Kennedy

Introduction

Classification

Taxonomy

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

Etymology

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

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Clinical Effects

Epidemiology

Habitat

  • Types A, B, and G found in soils. 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.
  • Endopores germinate in intestines and tissues upon death of animals.

Lifecycle

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

Transmission

  • Exogenous or endogenous.
  • Ingestion of preformed toxin from carcasses or rotting vegetation in contaminated food or water is most common source.
  • Infection 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; 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

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.

Vaccination

  • Toxoid vaccines have been used in waterfowl and mink.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references from VetMed Resource and PubMed.
  • Nunn F, Cave T A, Knottenbelt C & Poxton I R (2004) Association between Key-Gaskell syndrome and infection by Clostridium botulinum type C/D. Vet Rec 155(4), 111-115.

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