Ecological Interactions Influencing the Emergence, Abundance, and Human Exposure to Tick-Borne Pathogens

Tick-borne pathogens pose the greatest vector-borne disease burden in temperate areas of Europe and North America. We synthesize key aspects of tick life history that enable ticks to persist, spread and impact human health, including a two-year life cycle, multiple transmission pathways and dependence on hosts for tick feeding, movement and pathogen transmission. We discuss modeling advances that incorporate these traits in the context of climate-driven variation in tick feeding phenology. For established pathogens, such as the Lyme disease agent in the United States, we disentangle the linkages between land use change, habitat fragmentation and host diversity influencing human risk of infection along an urbanization gradient. We propose a coupled natural-human system framework for tick-borne pathogens that accounts for nonlinear effects and feedbacks between the enzootic cycle and human spillover. A deeper understanding of the eco-bio-social determinants of these diseases is required to develop more effective public health interventions.