NEW HAVEN, Conn - The Connecticut Agricultural Experiment Station (CAES) and US Biologic announced the publication of field trials showing the effectiveness of the delivery of an orally-delivered anti-Lyme vaccine targeting the major wildlife source of Lyme disease, the white-footed mouse.
The field trials were conducted over three years in the residential area of Redding, Connecticut. During that time, the authors observed significant drops in the numbers of mice infected with Borrelia burgdorferi, the bacterium that causes Lyme disease, and its infection in blacklegged ticks (Ixodes scapularis, the major vector associated with the disease) feeding on mice when comparing homes where the vaccine was and was not applied.
Specifically, the authors noted that, after one year of deployment, treated sites showed a 13X greater decrease in infection compared to control sites (i.e., 26% drop versus 2% drop). “Fewer infected ticks mean less infection in the field overall,” says Stafford, “So the decrease would be greater year-over-year that the vaccine is applied."
“Along with fewer infected mice, we observed a second effect also seen in previous laboratory-based studies,” notes Scott Williams, PhD, Agricultural Scientist at the CAES and a co-author of the study. “The vaccine causes the generation of antibodies in the mice. Previously infected ticks will ingest those antibodies when feeding on mice and be ‘cleared’ of infection. So, feeding ticks are a ‘xenodiagnostic marker’ of vaccine impact.” According to Williams, when non-infected mice consume vaccine-coated pellets, they are protected from infection with Borrelia burgdorferi. “Non-infected ticks, therefore, cannot pass the disease to other animals, including humans” he says.
The vaccine is currently undergoing the USDA regulatory process for commercial licensure. The research program was supported, in part, by U.S. Hatch Act funds, the Centers for Disease Control and Prevention (CK000182-03), and US Biologic.