Scientists use satellite to hit tsetse on target

Scientists have created a low cost satellite-guided plan to effectively control tsetse fly, using a decade’s worth of NASA satellite images of the Kenyan landscape to track tsetse movement and precisely target eradication efforts, in a fight that is currently costing Africa around $4.5bn and 3m cattle a year.

To eradicate the tsetse fly using traditional methods of trapping and spraying, based on old information on tsetse habitat, would cost $100 million in Kenya alone, according to Michigan State University (MSU) which carried out the satellite survey.

The Kenyan government is unable to invest that much in eradication, and such methods are anyway ineffective because of the difficulties in locating tsetse populations due to the insect's living and reproduction habits, climate variables and changing land use.

But the proposal developed by the MSU team would cost as little as $14m for the complete eradication of the fly, because of the more strategic targeting.

"As long as you have the right kind of climate for part of the year and a corridor for tsetse to move through, you'll find it," said Joseph Messina, a geographer at Michigan State University (MSU), who has been working on better ways to track the tsetse fly since 2007. Messina and his research team tapped into satellite data collected by NASA, mapping vegetation, temperature and land cover every 16 days.

Accurately targeting tsetse populations the scientists say could become increasingly important as climate change brings greater variability to conditions in Kenya. Climate fluctuation will lead the tsetse to new locations in search of its preferred habitat.

Based on conditions of rainfall, temperature and soil moisture, the MSU team developed a model programmed to identify the most attractive habitats for the tsetse fly and predict the time when the pests could arrive in those places based on previous movements and corridors.

This information creates a more effective eradication campaign, Messina said, attacking insects where they are in the present, rather than where they were a few years ago.

The tsetse then finds its prey through sight and smell, so the researchers lure the tsetse in with a target consisting of an insecticide-soaked cloth colored blue and black and stretched between two poles. The fly mistakes the target for dinner.

This combined method of locating and luring is now offering new hope in the fight against the fly, alongside other anti-tsetse breakthroughs.

Only recently a scientist from the Insect Physiology and Ecology (ICIPE) developed a unique repellant collar made up of body wash from compounds found on waterbucks, which scientists identified as having unique chemicals that reepel tsetse. Tied around the neck of animals, it slowly dispenses chemicals so strong that the tsetse flies picks the smell from a 100 meters away. The technology prevents 90 per cent of tsetse flies in cattle.