PS 31-178 - Novel Detection of Rickettsia parkeri in Amblyomma maculatum ticks found in Callaway County Missouri

Abstract: Vector-borne disease, more specifically from ticks, is a growing issue worldwide. Ticks are capable of transmitting an array of pathogenic bacteria of public and veterinary health concern. One such family of bacteria is Rickettsia, which lead to spotted fever infections upon establishment in their host; Rickettsia parkeri is one such member, which leads to Spotted Fever Rickettsiosis when a host is infected. This disease has seen growth in the Americas with an increase of confirmed cases in the United States and a growing fatality rate in South America. This disease is historically transmitted through the bite of the Amblyomma maculatum, commonly known as the Gulf Coast tick, in the United States. With increased efforts to restore prairie habitat in the Central Plains Region, there may increase potential habitat for ticks via mechanisms of providing suitable vegetation and habitat for hosts ticks feed upon and are potentially highly competent reservoirs for tick-borne pathogens. We sought to understand the role of prairie reconstruction in the presence of ticks and of tick-borne pathogens. From 2020-to 2021, we collected American Dog and Lone Star ticks from a reconstructed and remnant prairie in Callaway County, Missouri; to our surprise, we discovered several Gulf Coast ticks here as well. This tick originally habitats along the south eastern region of the country along the Gulf of Mexico, but recent reports has noted the expansion of the tick into northern regions. This discovery prompted us to begin screening for R. parkeri in collected ticks. Our goal for this project was to document any cases of R. parkeri within questing ticks found in Callaway County, Missouri. This was accomplished through first collecting and identifying Gulf Coast ticks through tick drags. Confirmed ticks were then screened through RT and conventional PCR. Positive reads were then sequenced to confirm the presence of R. parkeri. We confirmed 6 cases of R. parkeri within questing Gulf Coast ticks in Callaway County. As Missouri, and the Midwest subsequently, continue to experience a growing rate of tick diversity and density, monitoring these vectors for disease is crucial for the health of surrounding areas. The invasion of the Gulf Coast tick into this region not only affects the tick population native to this region, but the addition of R. parkeri introduces new disease to local fauna as well as the possibility of spilling over into human and domestic animal populations.