Evaluation of reservoir-targeted interventions to reduce the risk of tick-borne disease in the western United States

Vector-borne disease transmission is an emerging public health threat. The ecological determinants that govern the maintenance and transmission cycle of these diseases include factors such as habitat composition, land use change, and biodiversity. Empirical field studies are essential to understand the complex ways that these factors intersect to shape the emergence and risk of vector-borne disease, such as the tick-borne disease, Lyme disease. We used long-term community ecology data collected in a Lyme disease system in the western United States to inform ecologically-relevant tick intervention approaches. Over a two year treatment, we evaluated the effectiveness of topical rodent-targeted acaricide treatment to disrupt the pathogen transmission cycle ticks and the Lyme disease pathogen. Using acaricide-laced bait tubes, we targeted key reservoir hosts in the Californian Lyme disease system to reduce their tick burdens and the density of questing nymphal ticks. Our results show that tick burdens were significantly reduced on reservoir host species at treatment sites relative to control sites. Additionally, preliminary analyses indicate that the density of questing nymphal ticks was significantly lower the following year. These results indicate that Lyme disease management can effectively include host-targeted approaches to reduce both the density and potentially also the infection prevalence of human disease vectors.