Tick abundance and microorganism diversity in the 11 counties comprising the Choctaw Nation of Oklahoma

Tick-borne disease is an expanding public health concern within the United States. This is particularly true across the southcentral region where ecological diversity and human/vector interactions are highly variable. Southeastern Oklahoma encompasses the 11 counties that are within the Choctaw Nation of Oklahoma. This region has historically exhibited some of the highest reported rates of Spotted Fever Rickettsiosis and Ehrlichiosis within humans in the United States. However, the lack of localized surveys of tick vectors in the region have left gaps in our understanding of these diseases in the region. This study attempts to define the current distribution and abundance of tick species, as well as pathogen rates and prevalence within the 11 counties encompassing the Choctaw Nation of Oklahoma. Active field sampling was completed in Spring and early Summer 2024 and 2025 using standardized CO₂ traps and flagging at 27 sites located throughout 11 counties in the Choctaw Nation. The collection of 2055 ticks added four times the number of ticks to the historical records for this region. Detection rates for microorganisms were generally low across all samples when compared to historical reports in human cases from the region. Rickettsia amblyommatis (6.2%) was the most frequently detected microorganism in Amblyomma americanum, while ‘Candidatus Rickettsia andeanae’ (22.2%) was detected in Amblyomma maculatum and Rickettsia buchneri (5.9%) was detected in Ix. scapularis. In A. americanum, Ehrlichia chaffeensis (0.4%), Ehrlichia ewingii (0.6%), Panola Mountain Ehrlichia (0.12%) and Borrelia lonestari (0.6%) were detected. Overall, detection rates of these microorganism were below those historically reported in humans across the region. This work emphasizes the need to focus on the local environments in which different Native American tribes are at risk for tick exposure and tick-borne pathogens. This includes direct tribal engagement to provide a complete understanding of tick disease risk in a particular epidemiological landscape. By integrating native perspectives, future public health frameworks can more accurately and respectfully assess disease and risk within native communities.