Deer Tick—Transmitted Zoonoses in
the Eastern United States
Sam R. Telford III
Whereas plagues were once thought to mainly affect developing countries, people now are increasingly aware of the threat within American borders. Ticks have catapulted into public awareness, to the point that if it were not for AIDS, these eight-legged creatures and their bloodsucking habits would be the focus of astounding public attention. The relatively sudden appearance of these infections seemed enigmatic at the time but is now relatively well understood. In the case of Lyme disease, babesiosis, and ehrlichiosis, reforestation in eastern North America has permitted deer to proliferate. The proliferation of deer has permitted ticks to multiply. The multiplication of these ticks has permitted Lyme disease spirochetes, babesiae, and ehrlichiae to infect people in sites where these pathogens previously had been cryptically maintained. Residential development has created new habitat, exposing human residents and their companion animals to “emerging” infectious agents.
This chapter focuses on this well-studied example of how environmental perturbation has produced a significant public health problem and documents the extent and type of evidence that allows robust testing of hypotheses of causality. Intervention methods are described that are used or proposed for reducing the risk of humans acquiring a deer tick—transmitted infection, with the suggestion that such interventions may be used as tools for probing hypotheses of causality. Finally, the lessons learned from studies of the ecology and management of Lyme disease and that might be applied to other problems in conservation medicine are summarized.