Lizard feeding enhances Ixodes pacificus vector competence

Ixodes pacificus, the vector of Borrelia burgdorferi (Bb) on the west coast, feeds on a variety of hosts including rodents, birds, and lizards. While rodents are reservoirs for Bb and can infect juvenile ticks, lizards are Bb-refractory. Despite the range of bloodmeals for I. pacificus, it is undetermined how larval host bloodmeal identity may affect future nymphal vector competence. Here, we conducted a transcriptome analysis on I. pacificus to determine whether and through what mechanisms host bloodmeal history affects vector competency of I. pacificus for the Lyme disease pathogen. We experimentally evaluated the influence of larval host bloodmeal on nymphal I. pacificus Bb acquisition. Larval I. pacificus were fed on either lizards or mice and after molting, nymphs were fed on Bb infected mice. To investigate mechanisms by which host blood meal may alter vector competency, we compared gene expression profiles for I. pacificus ticks following mouse or lizard larval blood meals by conducting the first RNA-seq analysis on whole-bodied I. pacificus nymphs.