Poster presentation at the EEID conference in May 2018
Abstract
Transmission cycles of vector borne diseases often rely on competent host species maintaining the pathogen as well as reproduction hosts maintaining vector populations. This is the case for Lyme disease (LD), caused by Borrelia burgdorferi s.l and transmitted by ticks. However, how the relative proportions of competent and non-competent hosts in a community affect LD risk is still unclear. To test this, we collected data on host abundance (deer, rodents) and tick population from 20 sites in North East Scotland. Consistent with our expectation, prevalence of Borrelia afzelii (genospecies associated with rodents), was positively correlated with rodent abundance. However, prevalence was negatively correlated with deer density and decreased to 0% at high deer density (32ind/km2), regardless of rodent abundance. These results show how abundance of non-competent hosts can modulate transmission risk and are consistent with deer acting as dilution hosts at high densities in this system.
Dr Sara Gandy
Research Associate
My research primarily focuses on understanding the ecological drivers of tick-borne diseases to provide insights on the mechanisms involved in transmission cycles, especially on the interactions between ticks, hosts and pathogens. My research includes investigating the impacts of environmental changes (woodland restoration, rewilding) and host community composition (deer, rodent and birds) on tick-borne diseases risks in the UK. Some of my findings uncovered an opposing effect of deer densities on Lyme disease hazard through their positive effects on tick density and negative effects on infection prevalence. I also published work looking at spatiotemporal changes in tick distribution using passive surveillance data and I have been leading the National Tick Survey, which involves collaborating with stakeholders in thirty National Parks and recreational areas to collect ticks and test them for various tick-transmitted pathogens between 2021 and 2024. The goal is to understand disease hazard and temporal variation in areas visited by members of the public and deliver tick awareness messages.