Bacterial communities in Thai ticks: revealing geographical and methodological gaps in surveillance—a 25-year scoping review

Ticks serve as key vectors for a diverse range of bacterial pathogens that affect humans and animals worldwide. In Thailand, a comprehensive understanding of tick-associated bacterial diversity remains limited. This scoping review synthesises published data on tick-borne bacteria across Thailand from 2001 to 2025, focusing on bacterial diversity, host-vector associations, geographic distribution, and molecular detection methods. Literature searches in NCBI, Embase, and Web of Science identified 402 studies (272 after duplicate removal), of which 39 met the inclusion criteria. Ticks were collected from animals, humans, and the environment across four zoogeographical regions. Rhipicephalus, Haemaphysalis, Dermacentor, and Amblyomma were the most commonly studied genera. Eighteen bacterial genera, including both pathogens and endosymbionts, were identified, with Coxiella-like endosymbionts, Rickettsia, Anaplasma, and Ehrlichia being the predominant genera. Rhipicephalus ticks exhibited the highest bacterial diversity, while Rickettsia spp. were the most frequently detected pathogens. Conventional PCR remained the principal diagnostic method, with limited application of quantitative and metagenomic sequencing approaches. Geographic analysis revealed that most studies were concentrated in the Northern Peninsular and Central Peninsular regions, while the Continental section of the Indo-Chinese Mainland and Korat Plateau zones were under-represented, which may limit the accuracy of regional risk assessments, as surveillance gaps can underestimate both the diversity and prevalence of pathogenic organisms in these areas. This review emphasises the intricate nature of tick-host-pathogen interactions and highlights the importance of implementing standardised genomic surveillance nationwide within a One Health framework. The findings reveal key gaps in current surveillance efforts and advocate for incorporating genomic tick monitoring into Thailand's national One Health strategies to improve zoonotic disease preparedness.