Revolutionising livestock tick-borne pathogen control

This project will revolutionise how we approach livestock tick and tick-borne pathogen (TBP) control by providing knowledge and tools for proactive management.

Ticks are blood-feeding parasitic invertebrates that infest vertebrates worldwide. Of the >850 species of ticks worldwide, >150 are found in Africa, where they heavily parasitise livestock and are responsible for transmitting a range of pathogens to these animals. Tick-borne diseases are ranked among the most important livestock parasites and pathogens in Africa, and some are responsible for losses in excess of $170M/year. Heartwater (Ehrlichia ruminantium infection) has been implicated in the deaths of tens of thousands of livestock in Botswana since 2018 alone. This directly affects human food security and hence resilience of communities to global change. Climate change, spread of invasive ticks, and drug resistance threaten the sustainable control of ticks and tick-borne disease.

To support effective control of tick-borne disease, we need to better understand the processes driving TBP transmission. Models of TBP transmission are powerful tools which allow us to better understand the system and evaluate the impact of environment and interventions which would not be possible to evaluate in detail in the field or with in vivo trials. Prior research has largely had a one-tick, one-pathogen approach, and models focussed on one aspect of transmission dynamics. However, TBPs exist within the wider tick symbiome, and in changing environments, which may affect transmission.

We will conduct an unbiased cross-sectional survey of ticks in our study region, Botswana, identify all bacteria and protozoa carried by the ticks (symbiome), and relate symbiome traits and structure to environment, veterinary intervention measures, and disease. We will then develop and validate a mathematical model of E. ruminantium transmission in Botswana. Finally, we will use this model to evaluate the epidemiological impact of potential veterinary and policy measures, to develop guidelines for TBP control in Botswana.

This will be the first truly unbiased, country-wide survey of TBPs, and the first comprehensive model of African TBP transmission. The project is novel as it considers not only host-tick-pathogen interactions, but also tick symbiome and interactions with the environment. Recent devastating outbreaks of tick-borne disease in the Okavango Delta make this project timely, and Botswana the ideal case study region.