A Review on Sterile Insect Technique (SIT) and its Potential towards Tsetse Eradication in Ethiopia

Abstract

Tsetse transmitted trypanosomosis constitute the greatest single constraint to livestock and crop production in sub-Saharan Africa. There were a number of attempts for the past few decades in order to control tsetse and trypanosomosis in the continent. Control strategies based on chemical approaches targeting on the parasite and vector were extensively applied but in many cases control has not been sustainable in the long term. This might be due to the fact that insecticide resistance, re-invasion, environmental damage and poor control program implementation were the attributing factors. Thus, an alternative approach namely sterile insect technique (SIT) was developed and has been widely used in the control of tsetse flies as well as other agricultural pests. SIT involves production of target tsetse species in mass-rearing facilities, sterilization of the male and the release in sustained numbers in the natural habitat large enough to outnumber the wild male tsetse flies. It is species-specific and has no effect on other ‘non-target’ species. The SIT project in Ethiopia was initiated and designed in 1997 in the southern rift valley area with the collection and evaluation of entomological, veterinary, environmental and socio-economic baseline data. Consequently, the project confirmed the presence of only one species of tsetse fly, i.e. Glossina pallidipes Austen. The ultimate objective of the project is to create a tsetse-free zone in a 25, 000 square kilometer area suitable for agricultural development. In the long term, the project aims to develop adequate national capacity for applying the concept of Area-Wide Integrated Pest management (AW-IPM) with a SIT component to the other parts of the country affected by the tsetse and trypanosomosis problem. Mass production of tsetse flies should be achieved in order to meet the demands for the regular release of sterile males. Currently, there is a coordinated effort to produce adequate amount of Glossina pallidipes Austen to implement the actual SIT in the southern rift valley areas of Ethiopia. It is expected that once tsetse eradication is achieved in the southern rift valley, the area-wide strategy would eventually be expanded to all other tsetse-infested regions in the country, bringing enormous benefits to agricultural development in Ethiopia.

Keywords: Ethiopia, Eradication, SIT, Tsetse flies