Molecular detection of Rickettsia species in ticks infesting synanthropic hedgehogs in Southeastern Iran

Anthropogenic changes associated with urbanization can bring wildlife species into closer contact with livestock and humans, thereby increasing the risk of pathogen spillover. Recently, urban-adapted (synanthropic) hedgehog species, including Hemiechinus auritus (long-eared) and Paraechinus hypomelas (Brandt's), have been suggested as potential sources of zoonotic pathogens. The increasing number of tick-infested hedgehogs in urban areas and confirmed cases of human rickettsial infections in south-eastern Iran motivated this investigation to identify rickettsial species in ticks collected from hedgehogs to help assess their potential role in spreading tick-borne diseases. So, this study aimed to screen tick pools collected from synanthropic hedgehogs in southeastern Iran for Rickettsia spp. DNA and to perform presumptive species identification using partial gltA sequencing. Among 60 hedgehogs live-trapped and sampled in two cities (Zabol, Kerman), forty of the long-eared and five of Brandt's were tick-infested. We collected 68 ticks from 18 hedgehogs trapped in Zabol and 70 ticks from 27 hedgehogs trapped in Kerman. All collected ticks were adults and were morphologically identified as Rhipicephalus sanguineus s.l. or Rhipicephalus turanicus. Ticks collected from each individual hedgehog were pooled together and each pool consisted of ticks belonging to a single species collected from one individual hedgehog. Tick-pool DNA extracts were screened for Rickettsia spp. using a genus-level SYBR Green real-time PCR targeting the gltA gene. Screening-positive pools were confirmed by a TaqMan real-time PCR targeting the 16 S rRNA gene, and samples with Ct values < 31 were subjected to conventional PCR for amplification of an 834-bp gltA fragment. Species-level identification was performed based on partial gltA sequencing, BLAST analysis, and phylogenetic comparison. A total of 5 of 45 tick pools (11.1%) were positive for Rickettsia spp. DNA, including four Rhipicephalus sanguineus s.l. pools and one Rhipicephalus turanicus pool. Based on partial gltA sequencing, two positive pools were assigned as presumptive Rickettsia sibirica, two as presumptive Rickettsia rhipicephali, and one Rh. turanicus pool showed mixed detection of both species.The presence of Rickettsia spp. DNA in ticks collected from hedgehogs underscores the need for understanding of the potential involvement of synanthropic animals as reservoirs for tick-borne and other pathogens in different parts of Iran and surrounding areas.