WILDLIFE ORAL VACCINE AGAINST B. BURGDORFERI

DESCRIPTION (provided by applicant): Lyme disease is a significant public health treat, it is the most prevalent vector borne infectious disease in the United States, and its geographical range is expanding. The white-footed mouse is the major natural reservoir of Borrelia burgdorferi, the etiological agent of Lyme disease. Ixodes scapularis ticks acquire B. burgdorferi from infected mice (and other wildlife reservoirs) and transmit it to uninfected mice. This cycle maintains the zoonosis in endemic areas. Breaking the mouse-tick cycle by eliminating B. burgdorferi from its mouse reservoir and/or from the ticks that feed on them would markedly reduce the risk of Lyme disease. The goal of this proposal is to develop an oral immunization delivery system that can be safely deployed into the wild in endemic areas to vaccinate vertebrates known to be reservoir hosts for B. burgdorferi therefore breaking the enzootic cycle of this pathogen. In Phase I of this SBIR we proposed to develop an oral wildlife bait vaccine comprised of OspA, and if effective, OspC/OspA, using E. coli as a freeze-dried vehicle for immunogen delivery. In this Phase II proposal, the vaccine formulation developed in Phase I will be delivered orally to Lyme disease susceptible inbred mice. First, mice will be immunized by oral gavage inoculation and subsequently challenged by B. burgdorferi infected I.scapularis (nymphs). Second, a bait vaccine will be tested by admixing mouse chow with freeze-dried E. coli expressing the immunogen and challenging the mice as described above. Additionally, we will begin performance testing required for regulatory review. The development of an inexpensive, highly specific, effective, and easily distributable vaccine to decrease the prevalence of B. burgdorferi in tick populations around human communities could significantly reduce the incidence of Lyme disease cases within the several years of its introduction and will lead to the indirect control of human Lyme disease.