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Here come `fake cows` to fight tsetse flies
2008-04-22 10:18:34
By Editor
Experts at the Arusha based Tropical Insects and Pesticide Research centre (TIPR) cautioned last week that the population of one of Tanzania`s most harmful pests, the tsetse fly, is rapidly increasing.
Most alarming indeed, these pests are multiplying themselves without any limit in areas where livestock keeping is a dominant economic activity.
This is particularly a worrying development because historically, the tropical fly is known to be the vector of a parasite called Trypanosoma which transmits sleeping sickness to humans and nagana, which is the equivalent disease in cattle.
We know science has established that these parasites multiply in the blood, initially causing bouts of fever and joint pain, and if left unchecked can cross the blood-brain barrier and infest the central nervous system.
This can lead to confusion, sensory disturbances, irreversible brain damage in the sufferer and eventual death, if untreated.
The effects of nagana on cattle are equally devastating.
Found over an area of 10 million square kilometres in Africa, the disease is a major constraint on agricultural development in many poor countries, and is estimated to infect 46 million cattle in Africa alone and cause three million cattle deaths a year.
Yet, while in Tanzania we seem to be concentrating much of our tsetse fly control efforts on using expensive and environmentally not so friendly pesticides, little or no attention has been focused on how tsetse pests have been all but eradicated from parts of the continent with the help of a novel artificial cow.
Developed by an international group of researchers, including scientists from the University of Greenwich, the artificial cows attract tsetse by using kairomones (a blend of chemicals emitted by one species and detected by another) to mimic the smell of real cattle. The fake cattle are impregnated with insecticides that kill the tsetse attracted to them.
These artificial cows were first introduced into Zimbabwe in the mid-1980s, when thousands of cattle were infected with nagana.
The cases of nagana in Zimbabwe have plummeted to practically zero and have remained at this low level for all those years, largely due to the use of artificial cows, of which there are now more 60,000 in use. The fake cows also act as an effective barrier to stop tsetse re-invading areas cleared of flies.
Not only are artificial cows highly successful in controlling tsetse, but their use also results in a dramatic reduction in the amount of insecticide necessary to control this pest.
With only four artificial cows needed per square kilometre to ensure effective pest control, the use of insecticide is far more targeted than conventional and expensive widespread aerial and ground spraying, resulting in a greatly reduced environmental impact.
It is useful to note that during mid-1980s, when cases of nagana were at their peak in Zimbabwe, the government was spraying 100-200 tons of the DDT pesticide per year (now banned in many countries) to control the tsetse fly population.
This pest control policy has now been abandoned in favour of more effective and environmentally friendly alternatives such as artificial cows.
The sleeping sickness disease, according to World Health Organisation, is fatal if not treated.
This means, effective use of artificial cows could enable the nation save massive resources on heath care budgets, and instead concentrate on malaria, HIV/Aids treatment.
For fake cows to fool killer fly sounds a bit funny. Yet, we suppose we should be grateful for small mercies which science can provide us.
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