Shining the light on black fly, river blindness and the brain

World Brain Day 2022 is dedicated to the theme “Brain Health for all”. Research Fellow Dr Joseph Nelson Siewe Fodjo is a medical doctor and research officer at the Brain Research Africa Initiative (BRAIN) in Yaoundé, Cameroon. Currently he is participating in the Future Africa Leader Fellowship Programme (FAR-LeaF), at the University of Pretoria.

His PhD provided compelling epidemiological evidence that the neglected medical condition onchocerciasis, a tropical parasitic disease, can cause neurological symptoms such as epilepsy and neurocognitive decline. Dr Siewe Fodjo’s research is specifically involved in vector control activities to eradicate the blackfly that transmit onchocerciasis. Onchocerciasis is commonly known as river blindness and is regarded as an infectious disease that is poverty related.

River blindness normally manifests clinically as skin and eye problems. It is the world’s second leading cause of preventable blindness. 99% of people infected by river blindness live in Africa. The black fly is responsible for causing onchocerciasis and the related neurological conditions such as epilepsy and neurocognitive decline. The painful blackfly bites are a nuisance and a cause for psychological distress among affected communities.

Earlier attempts to control the abundance of blackflies at dam sites deployed chemicals to kill the developing larvae in the rivers, often with adverse repercussions for the environment and the emergence of resistance against the larvicides used. Larvicides are also expensive and require advanced technical skills to administer. This approach was eventually abandoned. The alternative that Dr Siewe Fodjo proposes is both eco-friendly and sustainable – and is urgently warranted.

“Using a novel slash and clear technique – cutting down trailing vegetation around fast-flowing rivers where the blackflies breed – we are successfully reducing blackfly biting rates and thus the transmission of onchocerciasis.” Although this technique is more eco-friendly than the use of toxic larvicides, its full impact has yet to be studied. Dr Siewe Fodjo is planning to fill this gap to minimise the negative ecological impacts of the lifesaving interventions around the Edea dam in Cameroon.

As shown by earlier PhD research conducted by Dr Siewe Fodjo in Sudan, a single intervention was enough to dramatically decrease the blackfly population for several months. Mathematical modelling suggested that the process can significantly accelerate the elimination of blackfly in endemic sites.

If the propose method proves to be beneficial, Dr Siewe Fodjo believes that the technique can be replicated at diverse water sites that will not only enhance, but also ensure, the  general and brain-health and well-being of the affected communities.

Dr Joseph Nelson Siewe Fodjo

Research Officer
Research Africa Initiative (BRAIN)


Prof Stephanie Burton

Prof Stephanie Burton

Research and Postgraduate Education
FAR-LeaF Program Director
University of Pretoria
South Africa

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Siewe Fodjo will ensure that his study can establish a stronger scientific network among African institutions, as well as relevant indigenous communities. He sees the project as being pivotal in bringing together experts from several fields and mobilising relevant stakeholders in a transdisciplinary manner to address not just a pestering, but a wicked problem.



The Future Africa Research Leader Fellowship (FAR-LeaF) is a fellowship programme, focussed on developing transdisciplinary research and leadership skills, to address the complex, inter-linked challenges of health, well-being, and environmental risks in Africa.