Development of a sequencing panel to characterise ticks and bacterial pathogens in the UK

: (Alternative Format Thesis)

Abstract

Bacterial pathogens are prevalent in UK tick populations. With expansion of novel tick species from Europe, and the geographical spread of native populations across the UK, an increase in the risk of novel pathogens infecting local tick populations could pose threats to both public and veterinary health. This creates a demand for a surveillance tool that can screen large numbers of ticks to monitor bacterial pathogens, which can be used to inform public health authorities and implement control strategies to limit human disease. This thesis includes a 16S bacterial microbiome survey of tick populations from a diverse woodland in the UK, results from this study informed the development of a molecular based sequencing panel to incorporate 16S bacterial microbiome analysis, source of host blood meal and species of tick using Nanopore sequencing. This panel of targets was validated using known positives, varying levels of engorged ticks, and varied tick species. The multiplex assay was directly compared to full length 16S sequencing, demonstrating its capability to characterise diverse bacterial communities in singular ticks of all life stages. The final version of the sequencing panel was used to characterise ticks collected from various wildlife and game species to reveal the differences in bacteria among hosts, the role of pheasants in Borrelia amplification and the possible co-infection of pathogenic bacteria among singular ticks. The panel also detected multiple host DNA in ticks, which could be remnant of a blood meal from a previous life stage. Findings from this thesis outline the affordability and applicability of using a multiplex panel using NGS sequencing in ticks for routine surveillance.

Date of Award	28 Jun 2023
Original language	English
Awarding Institution	University of Bath
Sponsors	UK Health Security Agency (UKHSA)
Supervisor	Samuel Sheppard (Supervisor), Matthew Wills (Supervisor), Edward Feil (Supervisor), Steven Pullan (Supervisor), Richard Vipond (Supervisor) & Jolyon Medlock (Supervisor)