Biological Control of Ticks With Particular Reference to Rhipicephalus appendiculatus

Abstract

Tick-borne diseases and the debility caused by tick infestation are major inhibitory factors on livestock production all over the world, but particularly in the tropics. In Africa, while most of the tick-borne diseases can be controlled by vaccination or chemotherapy, East Coast fever (E.C.F.) transmitted by Rhipicephalus appendiculatus remains to be dealt with. For this reason, the only presently-available method to achieve control of E.C.F. is the close interval application of acaricides to cattle in dips or sprays. This procedure has many disadvantages, the two most important being that, firstly; in the face of rigorous application of acaricides necessary to achieve control of E.C.F., ticks are likely to become resistant to available acaricides and the cost of producing new ones is becoming prohibitive. Secondly, once embarked on, a system of control using acaricides must be continuously maintained with 100% efficiency. The entire cattle population so-treated, never having been exposed to ticks or tick- borne diseases, will be completely susceptible to both the ticks and the diseases and if for any reason acaricide control breaks down catastrophies will occur. The most recent occurrence was in Zimbabwe (Lawrence, 1981).