Could putting grey squirrels ‘on the pill’ help protect human health?

Salford is a major partner in a multi-Institutional team that has just won a prestigious £1.25 million research grant from the UKRI and DEFRA. The project, entitled One Health approach to tick-borne disease control through manipulation of reservoir host communities at landscape scale involves Professor Richard Birtles from Salford University together with collaborators from the Universities of Greenwich and York, the Animal and Plant health agency and Forest Research.  

The main objective is to produce recommendations for minimizing risks of tick-borne disease which could occur through rewilding and afforestation. The UK's Net Zero 2050 policy contains bold plans to plant millions of trees each year to expand landcover in woodlands and forests, not only helping to sequester carbon but also helping to lower local temperatures as the climate changes. Such activities should be welcomed; however, changes in land use may have implications for the spread of unwanted non-native species and disease. Therefore, these plans must be evaluated to develop a robust strategy and avoid unintended consequences from our interventions.

The project will focus on Lyme disease, which is growing in the UK and across many parts of Europe.  People acquire the disease from the bite of infected ticks. Grey squirrels are one of the most common small animals present in woodlands and are host to both ticks and the bacteria that cause Lyme disease. Some experts have argued that the removal of grey squirrels by itself could result in a reduction in Lyme disease risk, but this has not yet been proven. This project plans to answer this question by determining what happens when grey squirrel populations are being reduced, and how this affects tick abundance and Lyme disease risk. The team will also develop models to predict what could happen to grey squirrel populations, and the ticks and diseases they host, as a consequence of increasing woodlands and forests in the UK while the climate is also changing.

Prof Birtles said: “The Salford work package will combine intensive field studies and state-of-the-art molecular laboratory techniques to provide an unprecedented insight into the complexities of Lyme disease ecology in the UK, allowing us to unravel relative contribution of different wildlife species to the natural maintenance of its causative agent”.

The project leader, Prof Steve Belmain of the University of Greenwich, added: “The project will exploit ongoing activities to control grey squirrels to help us understand the role they play in perpetuating Lyme disease and see whether reducing the population of greys can also reduce the prevalence of ticks and Lyme disease.  We hope to show that grey squirrels can be sustainably managed in humane ways by using contraceptive baits that will lower their population, helping the smaller red squirrel population to recover and expand so that more people can appreciate reds in the wild whilst reducing the chances of catching Lyme disease.”