Equis ISSN 2398-2977

Fusobacterium necrophorum

Contributor(s): Rachel Jago, Timothy Nuttall

Introduction

Classification

Taxonomy

  • Domain: Bacteria.
  • Phylum: Fusobacteria.
  • Class: Fusobacteria.
  • Order: Fusobacteriales.
  • Family: Fusobacteriaceae.
  • GenusFusobacterium.
  • Speciesnecrophorum.
  • SubspeciesF. n.subspp necrophorum and F. n.subspp funduliforme.

Etymology

  • F. n.subspp necrophroum previously = Biovar A of F. necrophorum.
  • F. n.subspp funduliforme previously = Biovar B of F. necrophorum.
  • fusus = a spindle; bacterium = a small rod; fusobacterium = a small spindle shaped rod.
  • nekros = the dead; phoreo = to bear; necrophorum = necrosis producing.
  • fundulus = a kind of sausage; forme = in shape of; funduliforme = sausage shaped.

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Clinical Effects

Epidemiology

Habitat

  • Normal inhabitant of the oropharynx and gastrointestinal tract.

Lifecycle

  • Reproduces by binary fission in anaerobic environment.

Transmission

  • Bacteria are excreted in feces.
  • May also be transmitted through infected material, bodily fluids and contact with mucus membranes.
  • Potentially zoonotic.
  • Exert pathogenic effects when anatomical barriers are breached allowing invasion of underlying tissues or in regions with poor blood supply.

Pathological effects

  • Multiple potential virulence factors:
    • Leukotoxin - including apoptosis and toxic lysis of neutrophils.
    • Hemagglutinins - adherence to epithelium (ruminal).
    • Hemolysins - damage erythrocytes, leading to impaired oxygen transport.
    • Dermonecrotic toxin - lysis of collagen.
  • Fusobacterium n.subspp necrophorum is the more pathogenic of the two subspecies.

Other Host Effects

  • Normal commensal flora of the oropharynx and gastrointestinal tract.

Control

Control via animal

  • Daily good hoof care.
  • Regular farriery attention, approximately every 6 weeks:
    • Ensure regular debridement of all loose tags and undermined and necrotic tissue.
    • Ensure correct hoof balance with application of a bar shoe if necessary to eliminate the shearing forces of sheared heels.
  • Adequate exercise to improve the blood flow and general health of the hoof.

Control via chemotherapies

Control via environment

  • Provide a clean and dry standing environment.
  • Collect feces.
  • Avoid waterlogged soil.

Vaccination

  • None available.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Dicks L M & Petrov K K (2013) Fusobacterium necrophorum, and not Dichelobacter nodosus, is associated with equine hoof thrush. Vet Microbiol 161 (3-4), 350-352 PubMed
  • Nagaraja T G et al (2005) Fusobacterium necrophorum infections in animals: Pathogenesis and pathogenic mechanisms. Anaerobe 11 (4), 239-246 PubMed.
  • Citron D M (2002) Update on the taxonomy and clinical aspects of the genusFusobacteriumClin Inf Dis 35 (Suppl 1), 22-27 PubMed.

Other sources of information

  • Markey B et al (2013) Non-spore-forming Anaerobes. In: Clinical Veterinary Microbiology. Mosby Elsevier, UK. pp 205-213. 
  • Quinn P J et al (2011) Pathogenic Anaerobic Non-spore-forming Gram-negative Bacteria. In: Veterinary Microbiology and Microbial Disease. Wiley-Blackwell, UK. pp 368-371.
  • Booth L & White D (2007) Pathologic Conditions of the External Hoof Capsule. In: Equine Podiatry. Saunders Elsevier, USA. pp 237-249.
  • Carter G R & Wise D J (2004) Non-Spore-Forming Anaerobic Bacteria. In: Essentials of Veterinary Bacteriology and Mycology. Iowa State Press, USA. pp 235-238.
  • Hirsh D C (2004) Non-Spore-Forming Obligate Anaerobes. In: Veterinary Microbiology. Blackwell Publishing, USA. pp 193-197.

Organization(s)

  • List of prokaryotic names with standing in nomenclature (LPSN). Website: www.bacterio.net.

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