Controlling Lyme Disease Where it Hides

Lyme disease is a bacterial infection spread through the bite of the blacklegged tick, Ixodes scapularis. It infects as many as 35,000 people in the United States each year, with associated annual healthcare costs estimated at $690 million. Although usually treatable in its early stages, Lyme disease can cause complications involving the joints, heart, and nervous system. In rare cases, debilitating symptoms may persist even after the infection itself has been successfully eliminated.

Lyme disease is caused by the bacterial pathogen Borrelia burgdorferi, which is considered enzootic (naturally widespread) in a number of wild animal hosts including the white-footed mouse. Juvenile blacklegged ticks become infected when they feed on the mice and then, as adults, spread the disease to deer and humans. Safety concerns and technical challenges have thus far prevented the development of a human vaccine against B. burgdorferi and Lyme disease.

Ventria Bioscience is working in partnership with the U.S. Centers for Disease Control and Prevention (CDC) on an alternative approach to protecting humans from Lyme disease. The goal of this research, funded in part by a $1.0 million grant from the Small Business Innovation Research Program (SBIR), Department of Health and Human Services, National Institutes of Health, is to develop a method to reduce or eliminate B. burgdorferi infection in animal host populations – and by extension, blacklegged ticks – through the use of a reservoir-targeted vaccine (RTV).

RTVs are increasingly used to manage zoonotic diseases such as rabies. Studies have shown that mice can be protected against B. burgdorferi infection with an injectable vaccine against the pathogen's outer surface protein A (OspA), and that vaccination of rodent reservoirs against OspA can dramatically reduce the prevalence of B. burgdorferi in ticks.

Ventria Bioscience and the CDC are working to formulate the OspA antigen for delivery as an oral RTV, and to produce it in sufficient quantities to enable its incorporation into targeted bait for large-scale vaccination of animal reservoirs. Adaptation of OspA to an oral vaccine would not only have the potential to decrease the risk of Lyme disease transmission to humans, but also provide a safer alternative to current RTV strategies that are based on live, weakened viruses.