Molecular Survey and Species-Specific Identification of Zoonotic Rickettsia in Rhipicephalus sanguineus sensu lato Ticks from Stray Dogs in Southeastern Iran

Background: Tick-borne rickettsioses are emerging zoonotic infections of global significance, causing febrile illnesses in humans and animals. Among canine-associated vectors, Rhipicephalus sanguineus sensu lato plays a central role in maintaining Spotted Fever Group (SFG) Rickettsia species in endemic areas. Stray dogs and their ectoparasites serve as key reservoirs facilitating the persistence and dissemination of pathogenic Rickettsia species. Despite their public health importance, data on species-specific prevalence and co-circulation of zoonotic Rickettsia in southeastern Iran remain limited. This study aimed to perform a molecular survey and species-level identification of zoonotic Rickettsia circulating in ticks from stray dogs in Kerman province. Methods: A total of ۲۵۰ Rh. sanguineus s.l. ticks were collected from ۵۰ stray dogs and pooled into ۵۰ samples. Genomic DNA was extracted and screened via SYBR Green real-time PCR targeting the conserved gltA gene. Positive samples were subjected to conventional PCR and Sanger sequencing to determine species identity and allow phylogenetic analysis. Data were analyzed to assess prevalence, co-circulation patterns, and seasonal distribution of the identified species. Results: Molecular analysis revealed ۲۰% (۱۰/۵۰ pools) infection with Rickettsia. Sequence analysis identified three distinct zoonotic SFG Rickettsia species: Rickettsia massiliae (۱۰%, ۵/۵۰ pools), Rickettsia conorii (۶%, ۳/۵۰ pools), and Rickettsia aeschlimannii (۴%, ۲/۵۰ pools). Rickettsia massiliae predominated across all sampling seasons, indicating sustained circulation