Arthan W.,Biodiversity Research Cluster |
Sumrandee C.,Biodiversity Research Cluster |
Hirunkanokpun S.,Ramkhamhaeng University |
Kitthawee S.,Biodiversity Research Cluster |
And 7 more authors.
Ticks and Tick-borne Diseases | Year: 2015
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. © 2014 Elsevier GmbH. Source