Environmental solutions to reduce the risk of current and future tick-borne zoonotic pathogens in the UK

The threat posed by tick-borne diseases (TBD) in temperate regions such as the UK is growing rapidly. Human exposure is often linked to woodlands that support high densities of tick vectors and key wildlife hosts of these pathogens, and are intensively used by people. Climate change and government policies to increase woodland connectivity and improve human recreational access are highly likely to increase risks of TBD in the UK. To mitigate this threat we need to better understand effects of landscape structure on the movement and habitat use of those wildlife species which are key hosts for ticks and zoonotic pathogens. We also need to understand how humans use landscapes, where they are most at risk of exposure to tick bites and whether exposure could be prevented by habitat and host management. Given recent shifts across Europe in the distributions of TBD and tick populations, it is also critical to understand how longer term climate and land use changes may affect the introduction, establishment and spread of TBDs.

Bringing together researchers from ecology, epidemiology, public health, and social science, TICKSOLVE aims to address these gaps. We will provide evidence for optimal greening and woodland restoration policies that will maximise benefits to biodiversity and human wellbeing while minimising human risks from current and future tick-borne diseases by:

1. Bringing together key national and regional level actors in health, land and biodiversity policy that interact with landscapes and TBD systems, to frame key risk scenarios and feasible environmental interventions for TBDs.
2. Better understanding how landscape structure shapes wildlife host distribution, habitat selection and movements and consequently impacts on ticks and TBD risk combining ecological surveys, pathogen genetics and computer modelling
3. Mapping how people use woodland landscapes and how this interacts with risk of encountering infected ticks to identify high risk areas for human exposure
4. Modelling how potential environmental barriers and interventions could reduce human exposure, integrating this knowledge of ecological interactions across the landscapes
5. Predicting how changes in woodland area and climate and patterns of bird migration may change TBD risks in the future
6. Co-developing interventions to minimise current and future TBD risks with stakeholders and policymakers that are locally appropriate.

The research will focus on three emerging pathogens that pose a risk to the UK. Firstly Lyme disease (LD) which is currently present in the UK and can cause long-term debilitation. Reported cases of LD have increased 10-fold since 2000, probably linked to an expanding distribution of its main tick vector, Ixodes ricinus. Secondly, tick-borne encephalitis (TBE) which has been recently detected in ticks in the UK with evidence of suspected human cases in 2019. TBE uses the same tick vector and can cause severe neurological damage and death with some 5,000 to 12,000 reported cases each year in mainland Europe. Thirdly, Crimean Congo Haemorrhagic Fever (CCHF), caused by a WHO priority pathogen CCHF virus, with epidemic potential, is expanding north-westward in Europe. It's tick vector, Hyalomma spp., was found recently on migratory birds arriving in the UK.

The TICKSOLVE project platform and approach of co-developing research, models and risk communication materials with stakeholders, accounting for diverse land management priorities, will enable formulation of future-proofed woodland and greening policies that minimise risks of these diverse TBDs. Furthermore, engagement with key global partners and networks through webinars and meetings will facilitate transfer of TICKSOLVE inter-disciplinary approaches to other rapidly changing tick-borne disease systems worldwide.