Success in Zanzibar: Eradication of tsetse

Tags: Other arthropods, Sterile insect technique (SIT)
A. R. Msangi, N. Kiwia, I. I. Malele, F. Mramba, K. M. Saleh, W. A. Mussa, K. G. Juma, V. A. Dyck, M. J. B. Vreysen, A. G. Parker, U. Feldmann, Z. R. Zhu and H. Pan, Area-Wide Control of Fruit Flies and Other Insect Pests, 2000.

There are about 22 species of tsetse flies found nowhere else in the world except in 36 countries of sub-Saharan Africa Tsetse flies transmit a debilitating and often fatal disease, trypanosomosis, which causes tremendous losses of livestock, and severely limits agricultural production (it reduces output of milk and meat, causes mortality, infertility and abortion in livestock, deprives the rural population of draught power and manure to improve and increase crop production) Tsetse flies also transmit human trypanosomosis, commonly known as ‘sleeping sickness’ It is estimated that over 55 million people living in rural sub-Saharan Africa are at risk from this fatal disease Tanzania’s Zanzibar Island is situated 35 km off the eastern coast and comprises two main islands, Unguja and Pemba Previous surveys revealed that out of the seven tsetse species found on mainland Tanzania, only Glossina austeni Newstead infested Unguja Island No tsetse fly was found on the island of Pemba The fly is responsible for the cyclical transmission of trypanosomosis in livestock, the causative agents being mainly Trypanosoma congolense and, to a lesser extent, T vivax It is estimated that in Zanzibar, the disease causes annual losses of US$2 million Since fly suppression by conventional techniques has often resulted in short-term success, Tanzania has always appreciated that the long-term solution to the trypanosomosis problem is the eradication of tsetse flies in the country In 1994, the International Atomic Energy Agency (IAEA) and the United Republic of Tanzania embarked on a project with the objective of eradicating tsetse flies from Zanzibar Island by applying the sterile insect technique (SIT) (Dyck et al 1995, in press) Previous tsetse eradication efforts in Tanzania using SIT, enabled the establishment of a modest capacity on tsetse mass rearing in Tanga (Williamson et al 1983) The Zanzibar tsetse project was successfully completed in 1997 The estimated cost was US$7,941,000 but only US$5,788,097 was actually spent Financial assistance came from international donors such as the governments of Belgium, Canada, China, Sweden, the UK and the USA The results and achievements of the Zanzibar tsetse fly eradication project are presented in this paper