Specifying host and pathogen associations of Amblyomma maculatum (Gulf Coast tick)

Amblyomma maculatum (Gulf Coast tick) is spreading from its historical range along the Gulf coast region northward along the Mississippi river and east of the Appalachian mountains and has recently become established in western Tennessee, a region with an increased risk for both Rocky Mountain spotted fever and ehrlichiosis. This tick feeds on birds and mammals, primarily cattle, and may play a role in the transmission of pathogens such as Rickettsia parkeri to humans (rickettsiosis), Hepatozoon americanum to dogs (hepatozoonosis), and potentially Ehrlichia ruminantium to cattle and wildlife (heartwater). The objective of this project was to determine pathogen associations (Borrelia, Ehrlichia, and Rickettsia species) within questing and host-collected (cattle, deer, rodents, and humans) A. maculatum. Currently, Rickettsia spp have been identified in 27% of questing and host-collected ticks. Of the samples sequenced, 83% (17% of the total collection) were identified as the human pathogen Rickettsia parkeri. One tick collected from a deer tested positive for Ehrlichia ewingii, another human and animal pathogen. None of the ticks were positive for Anaplasma or Borrelia spp. This project will help determine the role of A. maculatum in the transmission of tick-borne diseases in Tennessee by developing baseline prevalence and incidence data for monitoring changing A. maculatum populations and pathogen prevalence, and help to provide initial data necessary for the development of a monitoring and management plan.