Detection of Various Rickettsial Species in Ticks Collected from Small Ruminants in Western Iran.

ABSTRACT

Background: Most of the rickettsioses are transmitted by ticks, and often overlooked by the medical profession, but are clinically important as they cause major human diseases. Recent studies have shown the existence of some rickettsial species in Iran, but very little information is available about the status of rickettsial epidemiology and ecology. This study investigated the presence of Rickettsia spp. in ticks and ruminants in western of Iran by molecular methods. Materials and Methods: 250 blood samples were collected from sheep and goats, as well as 244 ticks were collected opportunistically from ruminants in the Kurdistan province. The collected samples were tested using a real-time quantitative PCR (qPCR) assay targeting the Rickettsia 16SrRNA gene. Rickettsia spp. positive by the qPCR were further amplified by conventional PCR of the gltA and OmpA genes. These ampliqons were further analyzed by sequencing. Results: The ticks species collected in this study included Rhipicephalus sanguineus, Rh. turanicus, Haemaphysalis concinna, and Dermacentor marginatus. In total, DNA of Rickettsia spp. was detected in 131 collected ticks (53.7%). Of the positives, Rickettsia slovaca (59.2%) and Ri. hoogstraalii (16.3%) were the most common species identified followed by Ri. raoultii, Ri. massiliae, Ri. sibirica, and Ri. conorii subsp. israelensis. In contrast, there were no positives observed in the blood samples collected from ruminants. Conclusion: The results indicate the presence of rickettsial species in ticks. The detection of these pathogens is significant because they cause clinical disease in humans. The results support the notion that the Iranian public health system needs to be more aware of these diseases.