Prevalence and Molecular Screening of the Rickettsia Genus in Rhipicephalus sanguineus sensu lato Ticks from Stray Dogs in Southeastern Iran

Background: Rickettsial pathogens are globally recognized as important zoonotic agents transmitted by ticks, causing a range of febrile illnesses in humans and animals. Stray dogs and their ectoparasites, particularly Rhipicephalus sanguineus sensu lato, serve as a critical reservoir for maintaining Rickettsia in endemic regions. The ecological interaction between these hosts and vectors facilitates the persistence and dissemination of rickettsial pathogens. Despite their public health significance, limited molecular data are available regarding the prevalence and seasonal dynamics of the Rickettsia genus in southeastern Iran. This study aimed to determine the molecular prevalence, seasonal distribution, and entomological risk of Rickettsia in Rh. sanguineus s.l. ticks collected from stray dogs in Kerman province. Methods: A total of ۲۵۰ Rh. sanguineus s.l. ticks were collected from ۵۰ stray dogs and grouped into ۵۰ pools for analysis. Genomic DNA was extracted from each pool and initially screened using SYBR Green real-time PCR targeting the conserved gltA gene, a standard marker for rickettsial detection. Positive samples underwent further confirmation using a TaqMan real-time PCR assay targeting the ۱۶S rRNA gene to validate genus-level identification. Data were analyzed to evaluate prevalence across different seasons and assess potential entomological risk. Results: Molecular screening revealed a ۲۰% prevalence of Rickettsia in tick pools (۱۰/۵۰). Positive samples were detected consistently across spring, summer, and winter, suggesting year-round circulation of the genus. The results indicate widespread presence of Rickettsia in the local Rh. sanguineus s.l. population. The persistent detection across seasons highlights the potential risk for spillover to humans and domestic animals, emphasizing the epidemiological significance of stray dogs as maintenance hosts. Conclusion: This study provides robust molecular evidence for the endemic circulation of the Rickettsia genus in Rh. sanguineus s.l. ticks in southeastern Iran. The observed prevalence