| Lyme Disease |
| Prevention of Borrelia burgdorferi infection in dogs |
Tick control!!!!
In enzootic regions, regular examination of dogs for ticks should become a part of everyday life. Since transmission of B. burgdorferi requires a minimum 24-48 hour feeding time, this is a very important component of LD prevention for dogs, as it is for humans.
Vaccination:
Bacterin:
There is a bacterin available, but there are concerns about the challenge system used to document the efficacy of this vaccine. (artificial syringe injection system; corticosteroid administration to enhance infectivity; inconsistent induction of clinical signs in the control dogs; short period of follow-up)
Recombinant ospA vaccine:
A recombinant vaccine containing only the ospA (outer-surface protein) from B. burgdorferi is now available. Using a more natural challenge system developed by Appel and colleagues at Cornell University, in which infected ticks are fed on dogs, both Chang and colleagues at Cornell and Coughlin and colleagues have demonstrated protection of dogs with a recombinant ospA vaccine.
Interestingly, Ab responses to ospA are initially lacking following natural infection, with these Abs developing only 5 months to 7 years after infection. This might, at first, make the use of this protein as a vaccine seem questionable. However, it's postulated that the body's lack of response to ospA may be the reason why natural immune responses are so inefficient in resolving infections, hence allowing the organism to persist in the body for prolonged periods. In addition, anti-ospA Abs protect by a very unique mechanism. The Abs are ingested by ticks during the early stages of feeding and actually inactivate B. burgdorferi within the gut of the tick, hence blocking transmission to the host.
A growing issue in LD vaccination for humans is the fact that there is substantial genetic and antigenic heterogeneity among B. burgdorferi isolates, suggesting that multivalent vaccines may be necessary to provide protection against a wide range of geographically distinct strains. Within North America and Europe, at least 5 seroprotection groups of B. burgdorferi have been identified.
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