Ticks feed on many different host species, including humans. While doing so, they can contract and spread infectious diseases but it remains unclear which hosts and which ticks drive the prevalence of tick-borne diseases. This research focuses on the bacterium, Ehrlichia chaffeensis, which is carried by the Lone Star tick and is known to cause disease in humans and to infect white-tailed deer. Lone Star ticks also feed on a variety of other species, including raccoons and Virginia opossums, whose role in E. chaffeensis outbreaks is unclear. The aim of this project is to advance our understanding of the multi-host transmission of E. chaffeensis, with a particular focus on how ticks choose their hosts. Using a combination of experiments on tick behavior, studies of tick genetic variation, and mathematical modeling of disease transmission, this project will identify how tick feeding preferences and the variety of host species contribute to the spread of E. chaffeensis. This work is relevant to public health and wildlife management, and may lead to the development of effective tick-borne disease prevention and control strategies. Some of the field work will be conducted on state- and federally-owned land, and the findings will be shared with the managers of these properties. Several undergraduate students will participate in the research, and will be trained in cutting-edge molecular laboratory techniques that will both enhance their studies and advance the goals of this project.