Zanzibar is a Tanzanian archipelago off the coast of East Africa. Both it and mainland Tanzania have fought a long, well documented battle with malaria. Globally, the disease infects over 200 million people annually and is responsible for killing approximately 500,000 people each year.
With a high-pitched humming, the drone took to the air. It sounded like a big mosquito—appropriate, since we were testing the use of drones for mapping aquatic malaria habitats. These shallow sunlit water bodies teem with mosquito larvae. In a matter of days, the larvae will emerge as adult mosquitoes in search of a blood meal. If one of those mosquitoes bites a human infected with malaria, it will become a vector for the disease and continue its deadly transmission cycle.
It’s been a real success story, leading to a notable decrease in the disease’s prevalence. Some areas of Zanzibar have seen prevalence levels drop from 40% of the population having malaria to less than 1%.
We know that once an adult mosquito has fed and rested, it will typically go in search of a mate. Then it moves on to a suitable location—an aquatic habitat like the fringes of river channels, roadside culverts and irrigated rice paddies—to lay its eggs.
In 20 minutes, a single drone is able to survey a 30 hectare rice paddy. This imagery can be processed and analyzed on the same afternoon to locate and map water bodies. This has proved to be highly accurate and efficient. This is all using one of the most popular off-the-shelf drones, the Phantom 3 made by DJI. These are about the size of a shoe box, weighing a little more than a bag of sugar (1.2 kg) and are used throughout the world for both leisure and commercial photography.
Despite these exciting advances, operators need to be mindful of the negative side of drones: invasion of privacy; collisions with aircraft and birdlife; their association with warfare. These are very real concerns for the public.
In Zanzibar, we worked alongside village elders to show them the drones and explain exactly what we plan to use them for. We also encouraged people to gather around when we were looking at live-feed footage from the drone’s on-board camera.