Document Type
Article
Publication Date
2026
DOI
10.4269/ajtmh.25-0674
Publication Title
The American Journal of Tropical Medicine and Hygiene
Volume
Advance online publication
Pages
11 pp.
Abstract
Spotted fever group rickettsioses (SFGR) are a growing public health concern in the United States. The increase in SFGR cases, coupled with the geographical expansion of tick species, including Amblyomma americanum and A. maculatum, necessitates a better understanding of Rickettsia species prevalence in newly established areas. Amblyomma maculatum is concerning because of its role as a Rickettsia parkeri vector. This study investigated the prevalence of Rickettsia species in ticks collected across 16 counties in southern Illinois, a region experiencing increasing reported SFGR cases. We collected A. maculatum, A. americanum, and Dermacentor variabilis and tested them by real-time polymerase chain reaction for R. amblyommatis, R. parkeri, and R. rickettsii and sequencing of the gltA gene for all Rickettsia species. Amblyomma maculatum was found in a wider range of counties than previously reported, with a prevalence of R. parkeri (16.4%) and Candidatus R. andeanae (28.7%). R. montanensis and R. bellii were detected in D. variabilis; A. americanum exhibited prevalences of R. amblyommatis of 48.5% in adults and 48.4% in nymphs. A positive correlation was observed between the density of R. amblyommatis-infected A. americanum and SFGR incidence rates. The range expansion of A. maculatum has introduced R. parkeri and Candidatus R. andeanae to southern Illinois, increasing the diversity of SFGR-causing agents. Although current evidence supports a role for A. americanum as driver of SFGR incidence in this region, continued surveillance is crucial to monitor the impact of A. maculatum expansion and potential shifts in Rickettsia spp. transmission dynamics.
Rights
© 2022 The American Journal of Tropical Medicine and Hygiene
"For articles for which the open access fee is not paid, authors must honor a 12-month embargo on current content, however they may deposit their paper in a public repository."
Original Publication Citation
Phillips, V., Flenniken, J. M., Mick, L., Chesser, L., Alfaro, E., Kim, C. H., Gaff, H., Allan, B. F., Stone, C. M., & Tuten, H. C. (2026). Surveillance for metastriate ticks and spotted fever group rickettsioses in southern Illinois. American Journal of Tropical Medicine and Hygiene. Advance online publication. https://doi.org/10.4269/ajtmh.25-0674
Repository Citation
Phillips, Victoria; Flenniken, J. Matthew; Mick, Levi; Chesser, Leta; Alfaro, Edna; Kim, Chang-Hyun; Gaff, Holly; Allan, Brian F.; Stone, Chris M.; and Tuten, Holly C., "Surveillance for Metastriate Ticks and Spotted Fever Group Rickettsioses in Southern Illinois" (2026). Biological Sciences Faculty Publications. 705.
https://digitalcommons.odu.edu/biology_fac_pubs/705
ORCID
0000-0002-4034-2684 (Gaff)