Drones vs mosquitos: using high and low-tech to fight malaria

In the middle of a muddy field next to a reservoir in Kasungu District, a team of scientists are hard at work. Boxes of equipment lie scattered around a patch of dry ground, where Lancaster University’s Michelle Stanton programmes an automated drone flight into a laptop perched on a metal box. The craggy peak of Linga Mountain (‘watch from afar’ in the local language) looms over the lake, casting its reflection in the water. A local cattle farmer stops with his herd to watch the unusual activity.
With a high-pitched whirr of rotor blades, the drone takes off and starts following the shoreline, taking photos as it goes. Once the drone is airborne, the team switch from high-tech to low-tech “bucket and spades” mode. Leaving the laptop, they collect ladles, rulers and plastic containers. Wearing rubber boots, they squelch through mud until they reach the water’s edge.

Choosing a spot amongst the lily pads, team members including UNICEF Innovation Intern Patrick Kalonde measure the water depth with a ruler and carefully scoop ten ladles of water into the containers. Using a mobile app, they record the GPS location of each sample. Back on dry ground, they wait for the water to settle and then use a pipette to count the number of mosquito larvae in each container.

The team from Liverpool School of Tropical Medicine and Lancaster University have been doing the same thing for two weeks at five reservoirs in Kasungu. They are collecting data to identify mosquito breeding sites, so that the larvae can be managed, reducing the number of adult mosquitos able to spread malaria.

“We stitch together the drone photos to create an aerial map of the reservior,” Michelle explains. “The drone has a near-infrared camera, which can detect different types of vegetation. Our water samples tell us where the mosquito breeding sites are, and we can plot these on the map. Then, using image classification software, we can identify the common features of these sites and predict where other breeding sites are.”

Deadly disease

Malaria is a serious issue in Kasungu District and other parts of Malawi. Along with pneumonia and diarrhoea, it is one of the top three causes of death among children under five years old. It is caused by a parasite transmitted person-to-person by certain types of mosquito. The disease is preventable and easily treatable if caught early, but if untreated quickly leads to severe complications and death.

Previous efforts to control malaria include distribution of bed nets for children to sleep beneath and posting health surveillance assistants (HSAs) in hard to reach areas. The HSAs hold regular clinics for children under five. They carry rapid diagnostic kits and malaria medication to treat any cases they find. For complicated cases, they provide initial treatment and refer the child to their nearest health facility.

At Kasungu District Hospital, there is a long queue of mothers waiting outside the Under Five Clinic in the morning sunshine. Most of them have infants or small children strapped on their backs in a colourful chitenje wrap. The mothers and children are registered at the clinic door. Inside, another long queue forms as the children’s temperature is checked and any child with fever is given a rapid malaria test.

In a corner of the waiting room, HSA Zondiwe Nyirongo sits wearing white plastic gloves and an apron at a desk already littered with used malaria test kits. “I’ve done 56 malaria tests so far this morning,” he says, referring to a written record. “Of these, 19 were positive. I do up to 300 tests every day, and around half of them are positive”

One of the children to receive a malaria diagnosis is 4-year-old Esther Gama, who arrived with her mother Mary. After the test result, they receive three days’ worth of anti-malaria medication for Esther. Mary accepts the diagnosis and medication without visible emotion, and it soon becomes clear that this is not her first time. “Esther is my only child,” she says. “She’s had malaria maybe six or seven times since she turned two years old. I’ve lost count.”

The family lives in Kaning’a, a village near the hospital, where Mary’s husband works in an electronics shop. “Esther got sick three days ago,” Mary says. “I gave her pain killers but she didn’t get better. Then last night she got a fever, so I brought her to the hospital this morning.”

One of the reasons children like Esther keep getting malaria is a lack of mosquito nets. “We don’t have any bed nets at home,” Mary says. “I received one when I was pregnant but that was a long time ago and we don’t have it now. We can’t afford to buy a new one.”

Mary’s calm exterior is somewhat deceptive. “I do worry about malaria a lot,” she admits. “Several children in our village have been admitted to hospital with serious cases. Some of them died.”

Kasungu District Medical Officer Liz Msowoya is based at the hospital. She says that malaria is the number one cause of hospital admissions and deaths among children under five in the district. “We’ve been seeing more cases this year,” she says. “This is partly due to the warmer, wetter weather but also because public health initiatives have not been effective enough.”

“We distribute mosquito nets but we know that not all families actually put their children to sleep under them,” Liz continues. “Some people misuse the nets for fishing or to protect crops. There is also a persistent rumour that they attract bedbugs, which is not true.”

Liz says that the fatalities are usually caused by people bringing their children to hospital too late. “We lack resources such as blood supplies for transfusions,” she explains. “There is also a high HIV rate in this area so relatives cannot always donate blood. Sometimes the health workers donate their own blood because they don’t want the child to die. But other times there is nothing we can do.”

Innovative approach

The purpose of innovation is to find new ways to tackle entrenched problems. Chris Jones from the Malawi Liverpool Wellcome Trust Centre, who is co-leading the drone project with Michelle, says that existing anti-malaria measures have led to a dramatic decrease in deaths over the last two decades, but that to reduce this further, new measures are needed.

“This is the first time the drones approach has been tried,” he says. “If we can prove the concept, this could become another malaria prevention measure to be used alongside bed nets and village health workers.”

The project made use of UNICEF Malawi’s Humanitarian Drone Testing Corridor. Launched in 2017 with the Government of Malawi, this allows universities, companies and individuals to conduct test flights within an 80km diameter area centred on Kasungu airfield. Tests must have a humanitarian or development application in the areas of transport, imagery or connectivity, and provide training opportunities for local Malawians.

As well as securing permission to fly, UNICEF has conducted community sensitization activities in the corridor, so that local people know what drones are, and what they are doing.

Michelle says that her mosquito project would not have been possible without UNICEF’s drone corridor. “Our contacts are in the health sector, not civil aviation,” she explains. “It would have been very difficult for us to get permission to fly and conduct the community sensitization ourselves. With the drone corridor, however, we could just come in and fly straight away.”

For staff at Kasungu District Hospital, meanwhile, anything that can be done to reduce malaria would be very welcome. “If drone flights could identify the breeding sites, our environmental health officers could go out and eradicate the mosquitos,” Liz says. “We would also need more funding and a directive from central Government, but it could definitely have a big impact.”

This story was first published in The Nation.