Tick-borne disease systems emerge from the shadows: the beauty lies in molecular detail, the message in epidemiology.

This review focuses on some of the more ground-shifting advances of recent decades, particularly those at the molecular and cellular level that illuminate mechanisms underpinning the natural ecology of tick-host-pathogen interactions and the consequent epidemiology of zoonotic infections in humans. Knowledge of components of tick saliva, now recognized as the central pillar in the tick's ability to complete its blood meal and the pathogen's differential ability to use particular hosts for transmission, has burgeoned with new molecular techniques. Functional studies have linked a few of them to saliva-assisted transmission of non-systemic infections between co-feeding ticks, the quantitative key to persistent cycles of the most significant tick-borne pathogen in Europe. Human activities, however, may be equally important in determining dynamic patterns of infection incidence in humans.