HosTiLyme

There is growing concern about the rise of vector-borne diseases (VBDs) in Europe and worldwide as they represent the majority of emerging infectious diseases, and severely affect human and animal health. The main European transmitters of VBDs are hard ticks (Ixodidae), especially Ixodes ricinus, transmitting a wide range of pathogens while feeding. The most common and important tick-borne disease (TBDs) is Lyme disease, whose symptoms depend on the genospecies of Borrelia burgdorferi s.l. that is transmitted. Among them, B. garinii causes the highly invalidating Lyme neuroborreliosis for which birds are competent hosts. In the UK, it has been hypothesized that the release of millions of common pheasants for recreational shooting may considerably boost the population of I. ricinus (as feeding host) and the spread of B. garinii (as competent vector). However, despite our efforts the comprehension of the spread of TBDs in the wild is severely hampered by the lack of an integrative approach investigating hosts, ticks and their microbial community as a unique set of interactions. In this project, I will investigate the ecological dynamics between birds, ticks and their bacterial microbiome. First, the physiological determinants underpinning differences in tick load between native and non-native birds will be examined. Second, I will investigate differences in tick physiology, fitness and host preference between and within native and non-native host species. Third, the role that (the diversity of) bacteria (especially Borrelia) within ticks play for tick fitness and host choice will be studied. The project will be mainly carried out at the University of Exeter (UK) under the supervision of a leading expert in host-parasite interactions, dr Barbara Tschirren. The analysis of the tick symbiont communities and tick physiology will be performed at MiVEGEC, France (secondment, dr Olivier Duron) and at the University of Sussex (secondment, prof. Jeremy Niven).