A white-tailed deer/lone star tick model for studying transmission of Ehrlichia chaffeensis

Animal models for Ehrlichia chaffeensis have been unsuccessful in recapitulating the natural disease cycle. We have developed an animal model for tick feeding and transmission using white-tailed deer (Odocoileus virgianus), the intracellular bacterium (Ehrlichia chaffeensis), and the lone star tick vector (Amblyomma americanum). Here, we report the acquisition and transmission of E. chaffeensis infections by refeeding male ticks in this experimental model. This finding is important because techniques for gene silencing are most successful for unfed adult ticks. Males are able to refeed several days after acquiring a tick-borne pathogen. Using refeeding male lone star ticks and RNA interference technology, we plan to decipher underlying molecular mechanisms involved in transmitting E. chaffeensis to a host via a lone star tick bite.