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Dr
Joseph Nelson Siewe Fodjo
Project Title
"Slash and Clear" for ONchocerciasis control and Epilepsy prevention (SCONE)
Project Objectives
Aims and specific objectives Our project has the following objectives: Investigate the feasibility and acceptability of S&C in selected Cameroonian villages which are meso/hyperendemic for onchocerciasis Evaluate the impact of sustained annual S&C on the transmission and infection burden of onchocerciasis in the study villages Use transmission dynamics models to predict the long-term impact of S&C on the burden of onchocerciasis in general and OAE in particular
Host Organisation
| Department | Institution | Country |
|---|---|---|
| Clinical Research | Brain Research Africa Initiative (BRAIN) | CM |
EDCTP Project
TMA2020CDF-3152
EDCTP Program
EDCTP2
EDCTP Project Call
Career Development Fellowship (CDF)
Study Design
Prospective, community-based trial
Project Summary
Onchocerciasis is a parasitic disease caused by Onchocerca volvulus and transmitted to humans via blackfly bites. Besides the usual skin and eye symptoms reported in persons with onchocerciasis, it is becoming obvious that the parasite also causes epileptic disorders. Despite years of annual mass treatment with ivermectin, onchocerciasis transmission persists in Cameroon especially in villages with loasis co-endemicity. Moreover, with the preventive measures instituted to limit COVID-19 transmission, the usual door-to-door distribution of ivermectin for onchocerciasis control may be implausible until the pandemic has been fully contained. Alternative elimination strategies are urgently needed to curtail onchocerciasis transmission and reduce its disease burden without violating the health safety guidelines in place. The effectiveness of the “slash and clear” (S&C) method in reducing blackfly biting rates has been demonstrated in hypoendemic onchocerciasis foci in Uganda. However S&C has not been evaluated in meso/hyperendemic settings, and there are no empirical data showing that this intervention is able to reduce onchocerciasis transmission and epilepsy incidence in the short term. This project seeks to follow-up on the transmission of onchocerciasis when annual S&C is implemented in affected Cameroonian villages, and the consequences on new cases of epilepsy after three consecutive years of intervention. Study villages with similar onchocerciasis endemicity levels at baseline will be randomised to annual S&C and no S&C. Outcome parameters such as Ov16 seroprevalence in children < 10 years, O. volvulus microfilarial load in the general population, and entomological measures (blackfly biting rates, blackfly infectivity rates) will be investigated prospectively to monitor onchocerciasis transmission patterns. The collected data will be used to construct mathematical models to predict onchocerciasis transmission and assess the added benefits of annual S&C interventions. By the end of the third year, an epilepsy survey will be conducted in all study sites. Based on the reported year of seizure onset among the identified persons with epilepsy, year-by-year epilepsy incidence will be established retrospectively and compared across studies villages with and without S&C. The scope of this project fits within the purpose of this call as it assesses a community-based, cost-effective approach to eradicate onchocerciasis (a poverty-related disease). Immediate spill-overs from this project will include important field-based data that can be used for onchocerciasis modelling, and eventual follow-up projects to investigate the impact of the S&C intervention on the epidemiology of epilepsy, which is considered by many as a disease of poverty (80% of cases reside in resource-limited settings).
Sites
Current Organisation
Brain Research Africa Initiative (BRAIN)
Current Job Title
Research Officer
Biography
Publications
Africa, the world's second-largest continent is home to 1.5 billion people, accounting for nearly 20% of the global population, (60% under age 25). By 2050, Africa's population will be 2.5 billion, and by 2035, more young Africans will be entering the workforce each year than in the rest of the world combined. Africa also hosts a rich social, cultural, and geopolitical diversity across its 5 geopolitical zones covering 54 countries. It is the most genetically, culturally, and linguistically diverse region on the planet. However, Africa's contribution to the global economy could be more significant if it urgently embraces the brain economy and leads in the development of new methodologies and approaches which can be exported around the world. In this paper, we explain our strategy to advance the Yaoundé Declaration for the Brain Economy, Brain Health, and Brain Capital. The Declaration has been endorsed by Cameroon's President, His Excellency Paul Biya, and demonstrates African leadership in global brain and society innovations, laying out a roadmap for how Africa can outcompete other economies by deftly deploying brain science-inspired policies and investments. We outline a new economic approach for African jobs, economic growth, sustainability, resilience, health, and well-being. The brain economy offers a broader framework than the current sustainable development goals (SDG) agenda. The Yaoundé Declaration is trans-disciplinary and cross-cutting across sectors: 32 sitting members of government from different sectors having co-authored this paper. It aligns with many aspects of the United Nations Pact for the Future and can accelerate the SDG.
Strong epidemiological evidence suggests that onchocerciasis may be associated with epilepsy-hence the name onchocerciasis-associated epilepsy (OAE). However, the pathogenesis of OAE still needs to be elucidated, as recent studies have failed to detect
Onchocerca volvulus
in the central nervous system of persons with OAE. Therefore, it was suggested that a potentially neurotropic virus transmitted by blackflies could play a role in triggering OAE. To investigate this hypothesis, adult blackflies were collected in an onchocerciasis-endemic area with a high OAE prevalence in the Ntui Health District, Cameroon. A viral particle-based shotgun sequencing approach was used to detect viral sequences in 55 pools of 10 blackflies. A very high abundance of viral reads was detected across multiple (novel) viral families, including viral families associated with human disease. Although no genomes closely related to known neurotropic viruses were found in the blackfly virome, the plethora of novel viruses representing novel species, genera and even families warrant further exploration for their potential to infect vertebrates. These results could serve as a first step for studying the viruses associated with the haematophagous blackfly, which also could be present in their nematode host
O. volvulus
. Exploring the diversity of viruses in blackflies should be included in the active surveillance of zoonotic diseases.
Malaria continues to pose a significant public health challenge in Cameroon, requiring effective prevention strategies. Long-lasting insecticide-treated nets (LLINs) are widely distributed as a key control measure, but their physical integrity and effectiveness need to be monitored. This study aimed to assess the condition and bio-efficacy of LLINs in 2 regions of Cameroon, namely Santchou in the West and Bertoua in the East. The study evaluated LLIN use and care using a structured questionnaire, following World Health Organization (WHO) guidelines for assessing physical integrity. Bio-efficacy was measured using the 3-min WHO cone assay. The results showed that the ownership and usage rates of mosquito nets were 93.91% and 72.70% in Santchou and 60.68% and 41.11% in Bertoua, respectively. In Santchou, 5.26% of LLINs were damaged, with 21.05% rendered unusable while in Bertoua, 29.41% of the used LLINs were damaged with 16.47% unusable. The knockdown rate with field mosquito populations was 65.49% with mortality rate of 61.24% in Bertoua. In Santchou, knockdown rate was 10.23%, and mortality rate 14.97%. The LLINs tested were found highly effective against susceptible strain. These findings urgently require the National Malaria Control Program of Cameroon to improve public awareness on consistent and proper LLIN usage and address the decline in LLIN effectiveness, particularly in cities like Bertoua and Santchou. Targeted interventions should focus on improving LLINs distribution, educating the population on correct usage practices, and implementing regular monitoring of physical integrity and bio-efficacy of insecticide-treated bed nets as these LLINs get degraded.
Introduction
A 2018 study found high epilepsy prevalence and mortality in the Maridi onchocerciasis focus (South Sudan). From 2019 onward, onchocerciasis elimination measures were strengthened in Maridi, and in 2020, an epilepsy clinic was established at Maridi County Hospital with free provision of anti-seizure medication. We investigated the changes in epilepsy-related mortality following these interventions.
Methods
Repeated house-to-house surveys (2018 and 2024) in three Maridi neighbourhoods (Kazana-1, Kazana-2, Hai-Gabat). The number of deaths that occurred during the two years preceding each survey among persons known to have epilepsy (PWE) was assessed in each home via verbal reports from the household head. Mortality rates were calculated and compared between surveys using the rate-ratio test.
Results
Between 2018 and 2024, epilepsy mortality in Maridi decreased 4.2-fold from 78.3 to 18.7 per 1000 person-years (p < 0.001). The decrease in mortality was most evident among the 11-20 year-olds: 6.9-fold reduction from 66.9 to 9.7 per 1000 person-years (p = 0.001). Age-standardized mortality ratio of epilepsy was estimated at 1.8 in 2024. Among the 184 reported deaths during the 2022-2024 observation period, the proportion of deceased PWE reduced from 9.7 % (2022) to 4.5 % (2023) to 1.8 % (2024), although without statistical significance (p = 0.175).
Conclusion
Strengthening onchocerciasis elimination measures and establishing an epilepsy clinic were followed by a drastic decrease in PWE mortality rate in Maridi. By preventing new-onset onchocerciasis-associated epilepsy and treating PWE with free anti-seizure medication, this two-pronged approach could mitigate the high premature mortality observed among PWE, especially adolescents. This strategy may be applicable to other onchocerciasis hotspots with high epilepsy burden.
Onchocerciasis, a neglected tropical disease, continues to affect millions in low- to middle-income countries, despite evidence of successful elimination efforts in some regions. The persistence of the disease is mainly due to suboptimal implementation of community-directed treatment with ivermectin programs, a critical component for achieving elimination. To address this issue, we propose increasing ivermectin coverage through health facilities to reach individuals who missed ivermectin during community-directed treatment with ivermectin campaigns. In addition, expanding ivermectin distribution through schools could further improve coverage among children. Health facilities could also play a key role in rapidly detecting onchocerciasis cases and identifying disease resurgence in areas where
Onchocerca volvulus
transmission has been eliminated. Moreover, health facilities and schools could serve as platforms for health education. Adapting these strategies to local contexts could strengthen the sustainability and impact of national elimination programs.