Borrelia burgdorferi

• Lyme disease
  • Caused by Borrelia burgdorferi
  • Reported in humans, dogs, horses, cattle, sheep
  • Ticks are the vector, which acquire the infection from small rodents, the reservoir hosts
  • Ticks transmit the infection to large mammals such as deer and sheep
  • Ixodes ricinus is the most common tick vector in Europe
  • Pathogenesis
    • Virulence of the borreliae requires a change in expression of an outer membrane protein following ingestion of blood by the tick
    • Borreliae multiply in the blood stream of susceptible hosts and disseminate throughout the body
    • Localisation in joints, brain, nerves, eyes and heart can occur
    • The associated lesions may be in part caused by the host immune response
  • CLinical signs
    • May be subclinical in endemic areas
    • Clinical manifestation depends on the site of localisation of organisms
    • Disease in dogs may cause fever, lethargy, arthritis, cardiac, renal or neurological disturbance
    • Horses suffer similar clinical signs but also lameness, uveitis, nephritis, hepatitis and encephalitis
    • Cattle and sheep may suffer from lameness
  • Diagnosis
    • Laboratory confirmation difficult due to low numbers of organisms and fastidious growth requirements
    • History of exposure to ticks in an endemic region and clinical signs
    • Rising antibody titre to Borrelia burgdorferi detected by ELISA
    • Immunofluorescence
    • Culture in Barbour-Stoenner-Kelly medium for 6 weeks under microaerophilic conditions
    • PCR
  • Treatment and control
    • Amoxycillin and oxytetracycline in the acute phase; prolonged treatment in the chronic phase
    • Tick control and removal
    • Vaccines including whole cell bacterins and recombinant subunit vaccines available for dogs