Molecular surveillance for Rickettsia spp. and Bartonella spp. in ticks from Northern Iran

Abstract

Tick-borne zoonotic diseases pose a threat to public health; hence, identifying the pathogenic agents associated with them is critical. The prevalence of Bartonella and Rickettsia in Iran is unknown. This study aimed to detect Rickettsia spp. and Bartonella species in ticks in northeast Iran and conduct phylogenetic analysis on these bacteria. Ticks from the sample bank in the Research Center for Emerging and Re-emerging Diseases were included in this study. The ticks were collected in 2017 and 2018 from domestic animals (sheep, goats, cows, camels, horses, dogs, and donkeys) and rodents in Golestan, Mazandaran, and Guilan provinces. Molecular methods were used to examine the DNA extracted from these samples to detect Rickettsia spp. and Bartonella species. The study examined a total of 3999 ticks. Ixodes ricinus (46.4%), Rhipicephalus turanicus (26.3%), and Rhipicephalus sanguineus (17.1%) were the most prevalent species. Among 638 DNA pools, real-time-PCR detected Rickettsia spp. in 161 (25.2%), mostly belonging to Rh. sanguineus (48.9%) and Rh. turanicus (41.9%). Golestan Province had the highest number of positive pools (29.7%). No positive samples for Bartonella were detected in a 638 pooled samples. Eight distinct Rickettsia species were detected in 65 sequenced samples, the majority of which were R. massiliae (n = 32, 49.2%) and R. sibirica (n = 20, 30.8%). Other species included R. rhipicephali (n = 3), R. aeschlimannii (n = 5), R. helvetica (n = 5), R. asiatica (n = 4), R. monacensis (n = 6), and R. raoultii (n = 1). The research findings may provide helpful information about tick-borne Rickettsiae in Iran and help to clarify the role of these arthropods in maintaining these agents. Rickettsia species were found to be circulating in three Northern provinces; thus, it is recommended that this disease be considered in the differential diagnosis of febrile diseases caused by tick bites and febrile diseases with skin rashes such as Crimean–Congo hemorrhagic fever (CCHF).