The Bacterial Community in Questing Ticks From Khao Yai National Park in Thailand

Abstract

Ticks are known vectors for a variety of pathogens including bacteria, viruses, fungi, and parasites. In this study, bacterial communities were investigated in active life stages of three tick genera (Haemaphysalis, Dermacentor, and Amblyomma) collected from Khao Yai National Park in Thailand. Four hundred and thirty-three questing ticks were selected for pathogen detection individually using real-time PCR assays, and 58 of these were subjected to further metagenomics analysis. A total of 62 ticks were found to be infected with pathogenic bacteria, for a 14.3% prevalence rate, with Amblyomma spp. exhibiting the highest infection rate (20.5%), followed by Haemaphysalis spp. (14.5%) and Dermacentor spp. (8.6%). Rickettsia spp. were the most prevalent bacteria (7.9%) found, followed by Ehrlichia spp. (3.2%), and Anaplasma spp. and Borrelia spp. each with a similar prevalence of 1.6%. Co-infection between pathogenic bacteria was only detected in three Haemaphysalis females, and all co-infections were between Rickettsia spp. and Anaplasmataceae (Ehrlichia spp. or Anaplasma spp.), accounting for 4.6% of infected ticks or 0.7% of all examined questing ticks. The prevalence of the Coxiella-like endosymbiont was also investigated. Of ticks tested, 65.8% were positive for the Coxiella-like endosymbiont, with the highest infection rate in nymphs (86.7%), followed by females (83.4%). Among tick genera, Haemaphysalis exhibited the highest prevalence of infection with the Coxiella-like endosymbiont. Ticks harboring the Coxiella-like endosymbiont were more likely to be infected with Ehrlichia spp. or Rickettsia spp. than those without, with statistical significance for Ehrlichia spp. infection in particular (p-values = 0.003 and 0.917 for Ehrlichia spp. and Rickettsia spp., respectively). Profiling the bacterial community in ticks using metagenomics revealed distinct, predominant bacterial taxa in tick genera. Alpha and beta diversities analyses showed that the bacterial community diversity and composition in Haemaphysalis spp. was significantly different from Amblyomma spp. However, when examining bacterial diversity among tick life stages (larva, nymph, and adult) in Haemaphysalis spp., no significant difference among life stages was detected. These results provide valuable information on the bacterial community composition and co-infection rates in questing ticks in Thailand, with implications for animal and human health.

Comparative Analysis of Tick-Borne Relapsing Fever Spirochaetes from Ethiopia and Nigeria

“…These two Borrelia goat sequences were deposited in the GenBank under accession numbers OP703387 and OP703388. The sequences aligned closely with those reported from Colombia [ 43 ], Thailand [ 44 ], and Zambia [ 13 ]. The 16S rRNA gene is known for its poor discriminatory power.…”

“…reported in humans from Tanzania [ 17 ]. Conversely, the flagellin and 16S rRNA Borrelia sequences from the Nigerian goats showed close similarity with the B. theileri reported in cattle from Zambia [ 13 ] and Columbia [ 43 ], as well as in Ixodid ticks from Thailand [ 44 ] ( Figure 8 and Figure 9 ).…”

High-throughput sequencing to detect the bacterial microbiome in Ixodes granulatus in China

“…Previous studies have used Next-generation sequencing describing the bacterial diversity within wildlife ticks and identifying the three novel Anaplasmataceae species [20]. The bacterial community of the three tick genera were found a 14.3% infection rate with pathogenic bacteria by metagenomics analysis [21]. At present, related bacterial community structure and diversity in the whole tick, four stages, midgut and salivary gland of I. granulatus ticks have not yet been reported.…”

Metagenomic profile of the bacterial communities associated with Ixodes granulatus (Acari: Ixodidae): a potential vector of tick-borne diseases

“…Investigations on the detection of microbial communities associated with ticks have primarily relied on traditional methods, i.e., conventional culture, cloning-based, or PCR, which are limited to detecting and characterizing a single bacterial type or species in each run. The advent of metagenomic approaches has overcome the limitations of traditional methods, enabling the identification of entire microbial communities associated with vector ticks using a minute amount of DNA (Carpi et al 2011, Bonnet et al 2017, Takhampunya et al 2021). With the development of high throughput Next Generation Sequencing (NGS) technology, the number of bacterial taxa detected in ticks of medical importance has risen sharply, including endosymbionts (Bonnet and Pollet 2021, Dall'Agnol et al 2021).…”