Tick repellents: Past, present, and future

Ticks are important vectors of human and animal diseases. One important protective measure against ticks is the use of personal arthropod repellents. Deet and the synthetic pyrethroid permethrin currently serve as the primary personal protective measures against ticks. Concern over the safety of deet and its low repellency against some tick species has led to a search for new user-approved, efficacious tick repellents. In this article, we review the history and efficacy of tick repellents, discovery of new repellents, and areas in need of attention such as assay methodology, repellent formulation, and the lack of information about the physiology of repellency.