Lyme Borreliosis

Lyme borreliosis is caused by gram-negative spirochetes of the Borrelia burgdorferi sensu lato complex, including 21 species and at least 30 strains of B. burgdorferi sensu stricto in North America and Europe, and B. afzelii, garinii, and others in Europe. Lyme arthritis is rare in seropositive cats; signs may be due to co-infection with Anaplasma phagocytophilum. Lyme nephritis in dogs is not due to spirochetal renal invasion but rather Lyme-specific antigen-antibody complex deposition and immune-mediated glomerulonephritis, with secondary changes of tubular necrosis/regeneration and interstitial nephritis. Ixodes ticks are the main vector of B. burgdorferi. For Lyme arthritis signs, doxycycline or minocycyline is recommended because of possible responsive co-infections. The prognosis for Lyme arthritis is excellent as the course is self-limiting or responsive to antibiotics within 1–2 days.