Ticks, tribes, and territories: Unraveling tick distribution and pathogen prevalence in South Central Oklahoma

Tick-borne diseases only occur where humans and animals interact in the same environment with infected ticks. As such, it’s important to know where specific ticks are located in a particular geographic area for effective risk assessment. Studies have focused on the distribution of ticks in Oklahoma for decades, but there is a gap in knowledge regarding tick distribution and pathogen prevalence in the South Central region, the same area encompassing the Chickasaw Nation. Epidemiological studies have reported that Native Americans are affected by tick-borne pathogen at significantly higher rates than non-Indigenous groups. No study, however, has collected ticks and assessed risk within this unique socio-cultural construct present in Oklahoma. This study aimed to characterize the tick distribution and pathogen of ticks collected in South Central Oklahoma and compare the abundance of ticks collected between indigenous-managed lands versus publicly managed lands. Twelve sites were chosen for a two-year study. Six culturally important sites were determined in cooperation with the Chickasaw Nation and three outdoor recreational sites, managed by local or state entities. Polymerase Chain Reaction (PCR) was used to characterize pathogen infection rates of ticks collected. A total of 3,761 ticks were collected during the study period, the majority being Ambylomma americanum (99.37%). Abundance of actively questing adults and nymphal A. americanum ticks significantly differed between public and Chickasaw sites, while there were no differences between for tick species and life-stages collected using CO₂. The likelihood of collecting Ehrlichia-infected A. americanum adults was significantly higher at public sites compared with Chickasaw sites, but there was no difference between sites for Rickettsia-infected A. americanum. While most Rickettsia-infected A. americanum adults were infected with R. amblyommatis, we identified three ticks infected with Rickettsia sp. strain 2019-CO-FNY, a newly identified Rickettsia associated with canines. This study is the first to evaluate tick abundance and infection status in a region under the jurisdiction of a specific Native American tribe that does not fit the traditional reservation model. It also highlights the importance of assessing vector-borne disease risk in tribal nations across the U.S. within their unique cultural, socio-economic, and geographical contexts. Additionally, it illustrates the necessity for direct collaboration with tribal governments to consider these factors within the study conclusions.