Highlights of contemporary research on host immune responses to ticks.

Host immune responses to ticks have been known since the early part of this century. This research has emanated from throughout the world with the most detailed studies originating from Australia and the United States. A review of all the studies to date indicates a diverse tick species list consisting primarily of Ixodid ticks, but a few Argasid species have been examined. Typically, research on this topic during the first half of this century has utilized the bovine host, whereas research over the past 20 years has concentrated on the rodent host. The emphasis of this research has been to define host resistance in terms of behavioral and physiological changes in the host, accompanied by changes in the feeding and reproductive potential of the ticks. The primary objective of this research is to develop an innovative tick control strategy that will allow greater and safer control than that afforded by acaricides. This paper highlights the study of host immune responses to ticks over the century to date. However, owing to the great growth in the fields of immunology and molecular biology, the greatest gains have been made from 1970 to 1985. Therefore, the emphasis of this review is on research reported during the last 15 years.