Impact of vector range expansion on pathogen transmission dynamics of Lyme disease in southwestern Virginia

Blacklegged ticks, Ixodes scapularis is the primary vector of Lyme disease in eastern United States. Borrelia Burgdorfei, the etiological agent of Lyme disease is transferred by ticks of Ixodes species. In recent years, its congener, Ixodes affinis has been expanding its range northwards from its southern population. We were interested in studying how the introduction of this new vector affected the interaction between the pathogen genotype and the host. We hypothesized that differential host use by I. affinis and I. scapularis would partly explain observed differences in B. burgdorferi infection prevalence and genotypic structure in southeastern Virginia. The result from our analysis does not support our hypothesis. Both species of ticks were found on small rodents and mammals. Ticks and mammals were able to acquire wide range of pathogen genotypes. We believe that range expansion of I. affinis is driven by various biotic and abiotic factors. Further studies is needed to understand the competition between the two tick species for food and resources and to see how it impacts the spread of