Getting rid of the tsetse fly
2002-02-20 11:51
Vienna - The UN nuclear watchdog said on Tuesday it would use nuclear technology to help rid Africa of the deadly tsetse fly.
Half a million people in sub-Saharan Africa are estimated to have been infected with sleeping sickness by the tsetse fly and 80 percent of them will likely die, according to the World Health Organisation (WHO).
Annual economic losses are put at $4.5 billion.
The Vienna-based International Atomic Energy Agency said in a statement the tsetse fly, which carries the parasite that causes sleeping sickness in humans and nagana in animals, was killing three million livestock animals every year.
"The impact of the fly is difficult to exaggerate," said John Kabayo, regional co-ordinator for the Pan African Tsetse and Trypanosomosis Eradication Campaign, inaugurated by the Organisation for African Unity.
"It's no accident that the concentration of much of the world's most acute poverty is in regions of sub-Saharan Africa infested with it," he said.
The WHO estimates that in some parts of the war-torn Democratic Republic of Congo in central Africa, sleeping sickness is killing more people than any other communicable disease, including HIV/Aids.
But Kabayo said there was hope in combating the epidemic, which began in the mid 1970s. Recently, the IAEA helped Zanzibar to rid itself of the tsetse by using a combination of conventional pesticides and nuclear technology.
Sterile males
The process is simple. Tsetse flies are bred in special centres and the males are exposed to a short burst of radiation, rendering them sterile.
After pesticides have sharply reduced the population, the sterilised males are released in large numbers into the breeding population, heavily outnumbering fertile males in the fight to mate. Over time, the tsetse population falls to zero.
"You do most of the work with chemicals, which takes months to achieve, and then you hit it with the sterilised insects to bring that 95 percent eradication to 100 percent," IAEA entomologist Arnold Dyck said.
PATTEC has already begun working with governments to implement the IAEA's two-step process of wiping out the fly in Botswana, Mali and Ethiopia.
The region-by-region process has to fight constantly against the threat of re-infestation of tsetse-free areas. "We're looking at decades before we've eradicated the fly from all of Africa," said Dyck.
The economic benefits of the programme are clear. PATTEC's Kabayo said that once Zanzibar began its campaign against the tsetse fly, milk production tripled, beef production doubled and the number of farmers who fertilised crops with manure jumped five-fold.
Scientists have failed to produce a traditional vaccine for humans or cattle because once in the blood, the trypanosome parasites, which the tsetse fly passes on, can change their outer protein coat into at least 1 000 variants.
The disease first attacks the body's immune system and then the central nervous system. However, drugs designed to treat the illness are either highly toxic or so difficult to administer that they become virtually unusable.
The disease can be treated if detected early but the WHO said only a fraction of those at risk were being screened.