Detection of Coxiella-like endosymbiont in Haemaphysalis tick in Thailand

• Published in: Ticks and tick-borne diseases 2015-02, Vol.6 (1), p.63-68
• Main Authors: Arthan, Watchara, Sumrandee, Chalao, Hirunkanokpun, Supanee, Kitthawee, Sangvorn, Baimai, Visut, Trinachartvanit, Wachareeporn, Ahantarig, Arunee
• Format: Article
• Language: English
• Subjects: Animals; Bacteria - classification; Bacteria - genetics; Bacteria - isolation & purification; Coxiella - classification; Coxiella - genetics; Coxiella - isolation & purification; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; DNA, Ribosomal - chemistry; DNA, Ribosomal - genetics; Female; Ixodidae - microbiology; Male; Phylogeny; Sequence Analysis, DNA; Symbiosis
• ISSN: 1877-959X; 1877-9603
• DOI: 10.1016/j.ttbdis.2014.09.005

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.