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Tsetse fly irradiation plan begins in Ethiopia

By Fred Pearce

20 May 2002

Ethiopia has begun its ambitious plan to become the first country in the world to eradicate the tsetse fly. The fly carries a parasite that causes sleeping sickness, Africa’s ancient scourge, and makes a quarter of the continent unfit for cattle.

The Ethiopian plan, unveiled in Addis Ababa on Sunday by its architect, government entomologist Assefa Mebrate, is to kill off the fly using the controversial sterile insect technique.

This involves breeding hundreds of millions of male flies, sterilising them with gamma radiation and releasing them into the bush from low-flying aircraft. Tsetse fly females breed only once, so if the male is sterile the population collapses.

The foundations for what will be the continent’s largest insect rearing centre, at Kaliti, south of Addis, are now being dug. Its director, Solomon Mekonnen, says: “Within two years the centre will be producing two million flies a week.”

The Ethiopian project is the first phase of a strategy backed by the Organisation for African Unity to eliminate the fly from the whole of the continent, which was launched in February with its main technical advisers, the International Atomic Energy Agency.

However, Africa’s leading expert on insect pests has expressed scepticism. Hans Herren, director of the International Centre for Insect Physiology and Ecology in Nairobi, Kenya, told New Scientist in March: “We think it is a crazy idea. There are so many tsetse that you are bound to miss a few. The populations will regenerate and you are back to square one.”

Wipe out

The Ethiopian project will begin in 25,000 square kilometres of sparcely-farmed bush in the country’s southern rift valley. Here conventional baited traps have already cut the fly population by 95 per cent around some villages. This has allowed farmers to start buying cattle for the first time since 1992, when tsetse extended its grip on the area.

The next step is to wipe out the remaining five per cent of flies by crowding out fertile males with irradiated sterile males. The first releases could begin within six months, says project leader Musie Kiflom.

With five species of tsetse in Ethiopia, each of which must be individually targeted, it could cost $200 million. “But we hope that in 10 years we will have eradicated the flies right to our borders,” said Assefa.

In Ethiopia, the trypanosome parasite does not cause sleeping sickness but it brings disease and death to cattle in much of the country’s lowland. Cattle are the country’s main source of meat, milk and traction of farmland.

“Right now, two thirds of our people are living on one-third of the land, and the biggest reason is the tsetse fly in the lowlands,” said the chairman of the country’s Science and Technology Commission, Mulugeta Amha.

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