A new artificial cow is helping to eradicate the tsetse fly from parts of Africa, thereby reducing the incidence of sleeping sickness, which is transmitted by the pest.
Although the fake cows do not look like cows (see picture right), they smell like them, attracting the flies with kairomones, a blend of chemicals emitted by one species and detected by another. The flies then die because the fake cattle are impregnated with insecticides.
Developed by an international group of researchers, including scientists from the University of Greenwich, the cows were introduced into Zimbabwe in the mid-1980s, when thousands of cattle were infected with nagana, a disease equivalent to sleeping sickness in cattle. Cases of nagana in the country plummeted to almost zero and have remained at this low level for the past five years. A total of 60000 cows are now in use in Zimbabwe.
Their use has also reduced the amount of insecticide needed to control tsetse flies. Dr Stephen Torr of the University of Greenwich's natural resources institute, said: “During the mid-1980s, when cases of nagana were at their peak in Zimbabwe, the government was spraying 100-200 tons of DDT pesticide per year 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.”
Funding for the project came partly from the United Kingdom's Department for International Development and partly from the European Union.
Sleeping sickness affects over 60 million people in 36 countries, according to the latest statistics from the World Health Organization. Sleeping sickness and nagana are transmitted to humans and cattle by tsetse flies infected with the parasite Trypanosoma brucei.
UNIVERSITY OF GREENWICH