Canis ISSN: 2398-2942

Borrelia burgdorferi

Synonym(s): B. burgdorferi

Contributor(s): Melissa Kennedy

Introduction

Classification

Taxonomy

  • Family: Spirochaetaceae.
  • Genus: Borrelia.
  • Species: burgdorferi.

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Clinical Effects

Epidemiology

Habitat

  • Ticks which carry Borrelia are found in wooded areas.
  • Reservoir in ixodid ticks and mammalian reservoirs such as deer and rodents.

Lifecycle

  • Two year lifecycle.
  • Four distinct developmental stages and three hosts are required.
  • Transtadial transmission in ticks occurs.
  • Tick larvae emerge in spring → infected by feeding on infected mice.
  • Larvae drop off and enter resting stage until following spring → molt to nymphal stage.
  • Nymphs feed for 3-4 days on new host → host becomming infected with spirochetes.
  • Nymphs drop off and molt to adult stage.
  • Adults feed for 5-7 days on large mammals.
  • Females overwinter and lay eggs the following spring.

Transmission

  • Tick bite - Ixodes spp are the arthropod vectors; species depends on the geographical location, eg in Europe, the tick involved is Ixodes ricinus.
  • In the US, Ixodes dammini and Ixodes pacificium are the principle vectors.
  • Rodents are reservoir hosts.
  • Canine and feline infections are not considered zoonotic.
  • Tick must be attached for several hours before infection of host occurs.

Pathological effects

  • Immune complexes and immunosuppression are thought to be involved in the pathogenesis.
  • Endotoxin is probably involved in the pathogenesis.
  • Dog: acute polyarthritis, classically migratory, chronic, recurrent, intermittent, non-erosive arthritis Arthritis: borrelial , glomerulonephritis Glomerulonephritis.
  • Cattle: abortions.
  • Horse: arthritis, uveitis, encephalitis, ocular, neural involvement and death in foals.
  • Man: skin rash (erythema migrans), sometimes arthritis, neural, cardiac sequelae.

Control

Control via chemotherapies

  • Amoxicillin Amoxicillin.
  • Tetracycline Tetracycline.
  • Azithromycin Azithromycin and ceftriaxone may be used in refractory cases.
  • Treatment regimes depend on the nature and severity of clinical signs but should be continued for minimum of 30 days.
  • Tetracycline treatment reduces the relapse rate.

Control via environment

  • Chemical control of tick populations in endemic areas has been relatively successful.
  • Daily removal of ticks from dogs and cats can be beneficial as ticks must feed for 2-3 days before disease transmission occurs.

Vaccination

  • Killed bacterin, OSpA vaccines available in the USA; primarily used in endemic areas.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references from VetMedResource and PubMed.
  • Appel M J G (1990) Lyme disease in dogs and cats. Comp Cont Ed Pract Vet 12, 617-625.

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