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.