Detection of Coxiella-like endosymbiont in Haemaphysalis tick in Thailand

• DOI: 10.1016/j.ttbdis.2014.09.005
• Publication Date: 2014-10-09T01:47:27Z
• Authors: Watchara Arthan; Chalao Sumrandee; Supanee Hirunkano...; Sangvorn Kitthawee; Visut Baimai; Wachareeporn Trin...; Arunee Ahantarig
• Keywords: DNA, Bacterial; Male; 0301 basic medicine; Bacteria; Ixodidae; Sequence Analysis, DNA; DNA, Ribosomal; 03 medical and health sciences; Coxiella; Animals; Female; Symbiosis; Phylogeny

In this study, we focused on the molecular detection of Coxiella-like bacteria using a PCR technique to identify Coxiella 16S rRNA sequences in Haemaphysalis tick samples (105 adults, 8 nymph pools and 19 larval pools). Seven Haemaphysalis species obtained from 5 locations in Thailand were evaluated in this work. Coxiella endosymbionts could be detected in samples representing all 3 growth stages examined. The results also revealed that only 4 of 7 tick species were positive for Coxiella-like endosymbiont: Haemaphysalis hystricis, Haemaphysalis lagrangei, Haemaphysalis obesa, and Haemaphysalis shimoga. Haemaphysalis shimoga demonstrated the highest percentage of Coxiella-like positive samples (58.33% with n=24), while Haemaphysalis hystricis had the lowest percentage; only 1 female tick was positive for Coxiella-like bacteria (n=6). Interestingly, the results indicated that female Haemaphysalis ticks tended to harbour Coxiella symbionts more frequently than male ticks (59.32% of females and 21.27% of males of all species studied). Phylogenetic analyses based on 16S rRNA sequences illustrated that Coxiella-like spp. from the same tick species always grouped in same clade, regardless of the location from which they were isolated. Moreover, a phylogenetic tree also showed that Coxiella-like endosymbionts from other genera (for example, the tick genus Rhipicephalus) formed a separate group compared to Coxiella-like symbionts in the genus Haemaphysalis. This suggests that a high amount of DNA sequence variation is present in Coxiella-like bacteria harboured by ticks.