Tick-borne agents in the fowl tick Argas persicus from northwest and northeast China

Abstract

Although tick-borne agents have been extensively studied, etiological investigations on soft ticks are still relatively rare. In this study, we collected 114 Argas persicus ticks from two provinces (Xinjiang and Heilongjiang) located in northwest and northeast China, respectively, and screened them for tick-borne agents. Two Rickettsia species were identified in A. persicus ticks from Heilongjiang Province: Rickettsia hoogstraalii (27.3%, 18/66) and a previously unidentified species (12.2%, 8/66). The 16S rDNA, gltA, groEL, and ompB genes of the latter have 98.8%, 93.1%, 94.3%, and 91.2% nucleotide identities to reported species, suggesting that it represents a novel species. It belongs to the ancient group of Rickettsia and is located in the basal position of the phylogenetic trees. Additionally, Coxiella endosymbiont was detected in A. persicus ticks from both locations with 100% positive rates. Furthermore, the Coxiella endosymbionts from different locations form distinct phylogenetic groups, indicating that one tick species can harbor different Coxiella endosymbionts.

Keywords: Argas persicus; Coxiella; Rickettsia hoogstraalii; Rickettsia sp..

Fig. 1

Phylogenetic trees based on the nucleotide sequences of 16S rDNA (809 bp), gltA (927–930 bp), groEL (1018 bp), and ompB (617 bp) genes of Rickettsia strains

Fig. 2

Phylogenetic trees based on the nucleotide sequences of rpoB (475 bp) and dnaK (560 bp) genes of Coxiella strains