A resource-based habitat concept for tick-borne diseases

Because tick and tick-borne disease distributions are so tightly linked to the environment, a robust conceptual background is necessary to build useful empirical and process-based models and to interpret results coherently with pathogen, vector and host ecology. This is especially pressing when considering that tick-borne pathogen circulation is a complex ecological system that has been studied in a great diversity of ways, producing results that may appear challenging to synthesise. We propose that a resource-based habitat concept can provide helpful leads to collect data, elaborate models and interpret and assemble upcoming and existing results. Two elements in the existing knowledge and its gaps, and in the current ecological context encourage us to explore such a conceptual framework. First, it is rare in the current practice to focus on the ecology of the pathogen, whereas this may be a key element in understanding the role of biodiversity in pathogen circulation. Second, the role of non-classical tick habitats (e.g. forest encroached areas and meadows) is getting more and more often highlighted, indicating that summarising tick habitat, or pathogen habitat, by a single vegetation class is not suitable. We revisit two simulation models (a cellular automata and an agent-based model) that focus on infected ticks and on tick population dynamics. In these models, the potential of a resource-based habitat concept can be highlighted. We then discuss how to implement this concept for studying the ecology of tickborne pathogens.