[ABIDJAN] People living in villages infested with tsetse flies could cut the costs of traps and insecticide-treated targets by up to 10 times, according to a study.
In field tests in Côte d'Ivoire and the Democratic Republic of Congo researchers studied the natural preference of two major vectors of human African trypanosomiasis (HAT) or sleeping sickness — Glossina palpalis palpalis and Glossina fuscipes quanzensis — to design more cost-effective traps.
They found that the flies were attracted to square-shaped targets of black cloth. They also found that the smaller squares — between 25x25 cm and 50x50 cm in area — were more cost-effective than the larger, oblong baits. This could make "considerable savings", the researchers say.
"Methods for controlling tsetse are too expensive and logistically demanding," said the study, published last month (2 August) inPLoS Neglected Tropical Diseases. It added that previous research had focused on the colour and size rather than shape of the traps.
Researchers have been developing various traps to capture and eliminate tsetse flies for years, including a screen based on the natural preference of the flies for the colours black and blue, according to Dramane Kaba, an entomologist at the Pierre Richet Institute, Côte d'Ivoire, and one of the study's authors. The screen is usually one metre tall and 0.8 metres wide, and consists of a mixture of black and blue cloth soaked in insecticide.
One of the aims of the new study was to reduce the size, and therefore the cost, of this screen while maintaining or improving its effectiveness.
To do this, "one has to study the level at which the insects fly [and] also understand their way of life", Kaba said.
Kaba said that the fight against HAT has typically focused on the disease itself rather than its vectors — and that new developments in traps will play an important role in eradicating the disease.
Koffi N'guessan, an entomologist at the University of Cocody-Abidjan, Côte d'Ivoire, said: "This study is good because it shows that tsetse traps can be easily used by the population. They do not require much explanation to learn the process of capturing and eliminating the tsetse."
But, he added that to sustain the fight against the disease, the commitment of populations living in areas infested with the HAT vectors is important.
People "must specifically follow the advice of researchers and also maintain the traps in the bush every day," he said.