By Mekonnen Teshome (Science Journalist)

As Eastern Africa scientists long ago discovered that tsetse flies are very attracted to blue-colored objects; they are now developing same color NGU traps to control the vectors that transmit Trypanosomosis in both cattle and humans.

Researchers working for International Centre of Insect Physiology and Ecology (ICIPE) have successfully designed traps that attract and kill tsetse flies by combining pieces of blue and black-colored clothes and nets, as the flies naturally love blue color.

A blue trap set-up to kill tse tse flies

According to Mr. Michael Okal, a post-doctoral researcher and entomologist at ICIPE, the baited trap is based on both visual (shape and colour) and olfactory cues including putting cow urine and acetone under the trap to attract the flies more.

ICIPE’s researchers announced the effective development of the trap, which has a “pulling effect”, as Kenyan Science Journalists Congress convened on November 18, 2019 in Mombasa, Kenya, the NGU trap which is also referred to as “artificial cow” is named after Nguruman, where it was developed and meant for savannah species of tsetse flies.

During a field visit in Tangini village in Kubwa South ward in Kwale County, farmers and cattle keepers confirmed that the newly invented trap is very useful in controlling the tsetse flies and protects their cattle from the disease.

Cattles getting injection

Josephine Wayga is a model farmer whose farm is used as a learning centre in demonstrating the traps to other farmers in Kwale County.

“I mostly communicate and teach what I know to other members of the community when we meet for our cattle’s blood test every month. The meeting is organised by the researchers as a way of monitoring the disease,” Wayga said.

The tsetse fly protection project was an initiative carried out in the Eastern Africa region that also includes Tanzania and Ethiopia.

In Ethiopia, ICIPE is also making similar efforts to curb the vectors of nagana (African Animal Trypanosomosis – AAT) and sleeping sickness (Human African Trypanosomosis – HAT).

Affecting human and animal health as well as negatively contributing to tourism earnings, the disease is a huge concern to national economies, for instance,  Kenya is losing nearly Sh20 billion annually due to tsetse fly infestation.

Apart from the NGU tsetse fly trap, ICIPE researchers say that they have developed a collar repellant technology, which has a “pushing effect”, for protecting livestock against trypanosomiasis disease.

A collar made of synthetic and animal- derived chemicals – 2-methoxy-4-methylphenol and a 5-constituent waterbuck repellent.

With collars which are put around the neck of the animal/cattle, the researchers identified the body odour of those animals that the tsetse flies do not bite like the waterbuck then put it in a slow-release mechanism and put it in a collar that is hanged on a cow. Thus, when the flies pass near the cattle, they think it’s a waterbuck and avoid it.

The repellant is an innovative technology that mimics the odours of animals that are not bitten by tsetse flies. The biomimicry technology is safe for the environment, cheap for farmers to use and it allows for mobility that the cattle can move when still protecting them in different areas.

“You could not keep livestock in this area ten years ago. When we first came here, 70 per cent of all the animals in this area were infected by the disease. And out of those, most died and those that survived could not provide milk, give birth or even be used for ploughing,” said Okal.

Both the repellant and the trap are environment-friendly, this means reduction in chemical uses.