Molecular evaluation of vector-borne pathogen infections: Our research is focused on characterizing vector-borne pathogens, particularly tick-transmitted rickettsial disease agents, Ehrlichia chaffeensis and Ehrlichia canis. We use the tools of molecular biology, immunology, animal models and cell culture systems. E. chaffeensis is the agent causing human monocytic ehrlichiosis (HME). It also infects dogs, white-tailed deer, goats and coyotes. E. canis is primarily responsible for the canine monocytic ehrlichiosis. It is endemic throughout the world, except Australia. These closely related pathogens remain in both arthropod and vertebrate hosts for long periods of time. This strategy may aid them in their parasitic lifestyle. Determining the molecular basis for persistence by these bacteria of the genus Ehrlichia will be important in order to accomplish our long range goals of developing effective methods of control against these tick-borne pathogens. Our research is focused on understanding the pathogen evasion mechanisms. Specifically, we study to define the protective host-immune response needed to eliminate the infection. We also study to define how these rickettsiales evade host responses in both vertebrate and tick hosts in order to support their life cycle.