Landscape and tick diseases

Landscape and tick diseases

In agricultural landscapes where cattle farming occupies a large area, pastures are adjacent to natural ecosystems frequented by diverse wildlife that share many common pathogens with cattle. The passage of pathogens is possible via vectors such as ticks, which are the main disease vectors in Europe due to their role in human (Lyme disease) and animal health. Furthermore, these landscapes are changing, in particular as a result of global changes, especially changes in land use.

Research Program

The OSCAR project, funded within the framework of the ANR Agrobiosphere programme and coordinated by Olivier Plantard, aims to explore the consequences of land-use changes at the landscape scale on acarological risk (density of infected ticks) through a cartographic simulation tool based on a spatialized model of tick population dynamics.

This project combines field studies, laboratory investigations and modelling approaches. Sampling is carried out at 24 sampling sites located in 4 different landscape areas for each of the two workshop zones studied (Zone Atelier Armorique (35) and Vallons et Coteaux de Gascogne (31)). To estimate tick densities, better understand their ecological requirements and search for hosted pathogens, tick collections and captures of small mammals are organised. The dispersion of ticks on a landscape scale is estimated using population genetics tools (analysis of the genetic variability of SNP markers distributed throughout the I. ricinus genome). Finally, deer movements in the landscape are estimated using GPS collars placed on captured animals. Pathogens (Anaplasma spp, Borrelia spp and Babesia spp) are searched for using molecular biology tools based on DNA extracts from ticks or blood samples taken from captured mammals (small mammals and deer).

Modelling studies combine two complementary approaches: (i) on the one hand, statistical approaches aimed at relating landscape characteristics, tick densities and pathogen prevalence, (ii) on the other hand, the development of a spatialized mechanistic model for the simulation of tick population dynamics, explicitly taking into account the landscape. This model is based on a coupling between a deer host movement model and a vector population dynamics model.

These models are intended to be used as cartographic simulation tools.

Partnerships

- UR INRA EpiA (Animal Epidemiology),

- UR INRA CEFS (Wildlife Behaviour and Ecology),

- UMR CNRS-Univ Rennes 1 EcoBio

- UMR CNRS-IRD-Univ Montpellier 1 et 2

Partnerships