Contents lists available at ScienceDirect Microbial Pathogenesis journal homepage: www.elsevier.com/locate/micpath Molecular detection of Coxiella (Gammaproteobacteria: Coxiellaceae) in Argas persicus and Alveonasus canestrinii (Acari: Argasidae) from Iran Asadollah Hosseini-Chegeni a , Mohammad Hassan Kayedi b,c, * a Department of Plant Protection, Faculty of Agriculture, Lorestan University, Khorramabad, Iran b Department of Parasitology and Mycology, School of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran c Razi Herbal Medicines Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran ARTICLE INFO Keywords: Tick Endosymbiontic Coxiella-like Q fever Phylogenetic relationship Iran ABSTRACT Background: Coxiella burnetii and non-C. burnetii bacteria or endosymbiotic Coxiella-like were reported in various tick species. We aimed to detect C. burnetii within soft tick species, Argas persicus and Alveonasus canestrinii. Methods: Argasid ticks were collected from different counties of Lorestan province, west of Iran. Partial frag- ments of 16S rRNA, IS1111 insertion sequence, com1, htpB, and icd genes related to Coxiella genus were se- quenced. Results: A partial 16S rRNA and com1 gene fragment as well as IS1111 was detected in four Ar. persicus and twelve Al. canestrinii pools. Moreover, partial htpB and icd gene was only detected in one pool of Ar. persicus. Conclusions: Detection of C. burnetii in tick samples was failed due to the occurrence of Coxiella-like en- dosymbionts and leads to misidentification. Thus, the house-keeping genes should be designated to distinguish C. burnetii within Coxiella-like endosymbionts. 1. Introduction Coxiella burnetii (Gammaproteobacteria: Legionellales: Coxiellaceae), the causative agent of Q fever, is an intracellular Gram- negative bacterium infecting humans and animals [1]. Q fever is a global zoonosis with a wide range of reservoirs such as mammals, birds, and arthropods. In humans, C. burnetii is considered mainly as an air- borne infection [2]. It has been reported that 49 tick species could be naturally infected by C. burnetii and species of the genus Coxiella [3,4]. In this regard, ticks act as vectors of the bacterium across wild verte- brates; particularly rodents, lagomorphs, and birds [4,5]. Although ticks do not play an essential role in the transmission of Q fever be- tween humans and animals, they are essential for the maintenance of bacterial agents in the natural transmission cycle [4,6]. Moreover, the highly virulent C. burnetii, Nine Mile isolate, was first detected in a guinea pig parasitized by a Dermacentor tick [7]. The molecular de- tection of C. burnetii depends on the most frequently used targets , in- cluding single chromosomal genes such as com1, htpB; plasmids (QpH1, QpRS); an insertion sequence (IS1111), and icd gene encoding isocitrate dehydrogenase [5,8]. Some of the target genes used to detect C. burnetii yielded Coxiella-like endosymbionts (CLEs), which are present in the tick's body and lead to misidentification [9]. According to different hypotheses, CLEs in ticks are derived from the C. burnetii ingested by ticks which feed on an infected vertebrate host. According to the an- other scenario, the virulent C. burnetii might have also evolved from vertically transmitted CLEs [10]. Cultivation of CLEs has failed till today, and their genetic diversity and biological similarity to C. burnetii have been poorly defined [11]. CLEs are widely occurred among dif- ferent tick species, suggesting a long coevolution relationship of Cox- iella and ticks [12]. CLEs infect different organs of ticks including midgut, Malpighian tubules, ovaries, and salivary glands [13]. It is believed that CLEs in tick organs such as salivary glands are a kind of nutrient provisioning bacterial resource supporting the biosynthesis of several cofactors essential for the survival of ticks [14]. Recently, Seo et al. [15], detected some CLEs isolated from the mammal's blood based on 16S rRNA-sequencing. CLEs were detected in 52.4% of Haemaphysalis longicornis ticks [15], 2.2% of I. ricinus and D. reticulatus ticks [16]. The prevalence of CLEs widely varies among tick species, ranging from 6.25% in R. sanguineus sensu lato to 100% in Amblyomma americanum [13]. Q fever is an emerging public health concern in Iran [17,18]. However, there are few studies targeting characterization of C. burnetii agent in Iran [19,20] focusing on human and animal hosts of Q fever agent rather than tick vectors. Owing to longer longevity in nature, argasid ticks may be more important than ixodid species in the survival and transovarial transmission of Coxiella bacteria. The soft ticks https://doi.org/10.1016/j.micpath.2019.103902 Received 11 October 2019; Received in revised form 27 November 2019; Accepted 28 November 2019 * Corresponding author. Razi Herbal Medicines Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran. E-mail addresses: hosseinichegeni@gmail.com (A. Hosseini-Chegeni), kayedi78@gmail.com (M.H. Kayedi). Microbial Pathogenesis 139 (2020) 103902 Available online 29 November 2019 0882-4010/ © 2019 Elsevier Ltd. All rights reserved. T