Detection of Rickettsia montanensis in Dermacentor variabilis in Northern Wisconsin

Background: Spotted fever rickettsiosis is caused by a group of closely related bacteria that includes Rickettsia rickettsii, the etiological agent of Rocky Mountain spotted fever. Recently, Rickettsia montanensis has been reported to cause clinical and subclinical symptoms in both humans and animal models. Materials and Methods: In this study, we collected ticks in Ashland County, located in northern Wisconsin, and tested 16 ticks identified as Dermacentor variabilis for the presence of rickettsial bacteria using PCR techniques. Results: Four positive results identified using gel electrophoresis were then sequenced to determine the rickettsiae species. Of the samples sequenced, three matched for R. montanensis (∼19% of the 16 ticks tested). Conclusion: In this study, we report the presence and prevalence of R. montanensis in northern Wisconsin.