Meet Nigeria’s human flycatchers luring bloodsucking insects in the name of science | Global health

EVery Monday and Tuesday morning, Bosede Oluwaokere, 48, wakes up at the house in the city of Ilorini in western Nigeria, dresses and walks in a stream nearby. She sits under a tree and pulls her skirt around her thighs. During the following six hours, she stays in the same place while waiting for a specific type of fly to land on her, so that she can catch her using a small plastic tube.

OluwaOkere is a human fly fly – or a human landing socket, because the World Health Organization (WHO) knows it – which is considered to be “the Order” to collect black flies. The black flies, which reproduce near the rivers, are insects which push the blood which distribute the neglected tropical onchocercois, also known as the river blindness.

When someone is bitten by an infected black fly, the larvae of the parasite Volvulus onchocerca Invade their bodies and become verses that can live up to 15 years. Female worms produce thousands of microscopic larvae that spread throughout the body. If the larvae reach the person’s eyes, this can cause permanent loss of sight.

When the black flies suck the blood of an infected person, they can then transmit it to someone else, they bite.

“I like this work,” said Oluwaokere, who was recruited as a volunteer by the Ministry of Health. “I’m not afraid to do it, because I like my community and I want it to be free from illness.”

It receives an allowance of 10,000 Nairas (just under £ 5) per month by Sightvers, an international health charity.

In Nigeria, around 40 million people are at risk of onchocercines. There are 120,000 cases of related blindness in the country and several thousands suffer from disabling complications of the disease.

According to the WHO, in 2023, nearly 250 million people needed preventive treatment against onchocercois worldwide. More than 99% of infected people live in Africa and Yemen; The remaining 1% live on the border between Brazil and Venezuela. The global study of the burden of the disease estimated in 2017 that 14.6 million infected people already had skin disease and 1.15 million had a loss of vision.

The WHO roadmap for neglected tropical diseases (NTD) has identified ONCHOCOIS as one of the targeted diseases for elimination and has set ambitious objectives to be achieved by 2030.

There is no remedy for onchocerors, but WHO recommends mass administration (MDA), where a large number of people receive medication to prevent its spread. The current treatment is given by the pharmaceutical company Merck under the brand of Mectizan. It is administered to populations at risk once or twice a year up to 15 years. As more and more people are treated and less are infected with the disease, black flies become less likely to pass the parasite.

After several MDA cycles, the Ministries of Health of affected countries are carrying out tests to determine if they can declare that they have eliminated the disease. First, people in risk areas are undergoing blood tests of jackets to see if they carry the disease. Then, black flies in endemic areas should be tested to see if they still transport the parasites. In Nigeria, the goal is to test 6,000 black flies. But first, they must be captured and human flies are the favorite method.

For years, there have been ethical concerns about the use of people and bait for research purposes. “It makes me very uncomfortable because it is a risky practice,” explains Louise Hamill, director of onchocerciasis at Sightsavers. “We ask a human being with a family, a life and a work, to put everything on a break and to sit next to a river for [a significant chunk] of the day. They put themselves at high risk of black flies, but they are also outside so that they can bite by a tsetic fly and have a sleep disease, or by a mosquito and obtain malaria or dengue. They could be bitten by a snake, exposed to a lot of direct sun, sunburns, heat, rain. »»

Oluwakere is not discouraged by such risks, but his volunteer colleague, Olamilekan Adkekeye, a 26-year-old university student who is a quarter afternoon after her on Monday and Tuesday, had to flee after seeing a black snake. “I don’t know what type of snake it was, but fear made me flee. I hid in a nearby store and returned a few hours later. ”

WHO also recommends using Esperanza window traps (EWT), where flies are captured on sticky surfaces, to catch black flies. They were first proposed as a method to collect flies in 2013. Although they worked well in South America, they were not as effective in Africa.

“I think it’s because of the human factor,” said Dr. Maria Rebollo Polo, leader of the World ONCHOCARCs elimination program. “The attractiveness of flies at flies seems so powerful that it is difficult to imitate.”

To avoid using people, Sights saving and the Global Institute for Disease Elimination are working on the development and optimization of EWT. Research in Malawi, Mozambique, Ghana and Ivory Coast, which should be published this year, plans to deploy variations in traps that use carbon dioxide to imitate human breathing, adhesives and clothes of different colors, and even the simulated smell of sweaty feet.

Rebollo says that human flies, although rudimentary [research] Technique “, are still used due to a lack of funding.” Obviously, if the neglected tropical diseases aroused more interest and if we had more resources, we would now have better techniques that would reduce any potential human discomfort, “she said.

But it argues that humans are necessary for multiple research purposes, such as blood tests on children to monitor malaria or clinical trials where people are exposed to drugs. In each country, there are ethical committees that determine if and how people should be used for research purposes.

Back in Ilorinini, OluwaOkere and Adekeye are happy to be able to contribute to possible progress in health, but they would like to be paid more. “The amount of money I receive is too small,” explains Adekeye. “I have other sources of work that pay better, but I choose to do it to help my community.”