Molecular detection and diversity of spotted fever group Rickettsia isolated from ticks in Iran

Background: This study aimed to identify Rickettsia spp. and their circulation in ticks collected from sheep in the Khuzestan province, Southwest Iran. Methods: Four hundred and forty adult hard ticks were collected from the parasite-infected sheep from nine cities of Khuzestan province. DNA samples were extracted and subjected to the single-round polymerase chain reaction amplification of citrate synthase gene (gltA). Results: The tick species were identified as Hyalomma marginatum, Hyalomma anatolicum, Hyalomma dromedarii, Hyalomma schulzei, Rhipicephalus bursa, and Rhipicephalus turanicus. The presence of Rickettsia spp. was observed in half of the collected ticks (50%). For a definitive identification of Rickettsia spp., the amplicons (n: 10) were directly sequenced. Sequencing and phylogenetic analyses revealed the definitive presence of Rickettsia aeschlimannii (60%), Rickettsia massiliae (30%), and Rickettsia conorii (10%) in the infected ticks. Conclusions: The results indicated a significant incidence of tick-borne Rickettsia spp. and their unequivocal circulation in Southwest Iran. Hence, the prevalence of spotted fever group Rickettsia should be detected in suspected humans and domestic animals in wider areas of Iran.