ArticleParasites & vectors2021
Onchocerca volvulus transmission in the Mbam valley of Cameroon following 16 years of annual community-directed treatment with ivermectin, and the description of a new cytotype of Simulium squamosum.
Article in Parasites & vectors, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 18 papers, 1 of them a synthesis that pooled it.
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Who cites it
18 citing papers in PubMed, 1 synthesis or guideline pooled it, 23 citations in OpenAlex.
- Current Gaps in Survey Design and Analysis for Molecular Xenomonitoring of Vector-Borne Neglected Tropical Diseases: A Systematic Review.Tropical medicine & international health : TM & IH · 2025Pooled it
- Spatial and seasonal dynamics ofParasite epidemiology and control · 2026Article
- Public health impact of nuisance biting blackfly (Simulium damnosum s.l.) along the Asejire dam in Southwest, Nigeria.BMC public health · 2026Article
- Impact of seasonal changes on human onchocerciasis transmission and disease elimination.International health · 2026Review
- The risk of onchocerciasis infection by human population movements between high and low transmission settings in Ghana.PLoS neglected tropical diseases · 2026Article
- Knowledge and Practices of Four Onchocerciasis-Endemic Communities in Cameroon.Microorganisms · 2025Article
- Model-Based Geostatistical Mapping of the Prevalence of Onchocerca volvulus in Cameroon between 1971 and 2020.PLoS neglected tropical diseases · 2025Article
- Cameroonian blackflies (Diptera: Simuliidae) harbour a plethora of RNA viruses.Virus evolution · 2025Article
- Effects of Five Years of Treatment of Onchocerciasis with Ivermectin under Community Guidelines in Resurgent Areas of Burkina Faso: A before-and-after Analysis.Tropical medicine and infectious disease · 2024Article
- Modelling onchocerciasis-associated epilepsy and the impact of ivermectin treatment on its prevalence and incidence.Nature communications · 2024Article
- Community Perceptions of Blackfly Nuisance and Acceptability of the "Slash and Clear" Vector Control Approach in the Ntui Health District of Cameroon: A Qualitative Study.International journal of environmental research and public health · 2024Article
- Significant reduction of blackfly densities in persistent onchocerciasis area following pilot implementation of an environment friendly approach (Slash and Clear).Scientific reports · 2024Article
- Optimized strategy for real-time qPCR detection of Onchocerca volvulus DNA in pooled Simulium sp. blackfly vectors.PLoS neglected tropical diseases · 2023Article
- Trends in black fly density, parity and infection rates from riverside to villages of the Bafia Health District in Cameroon: implication for onchocerciasis vector control.Parasites & vectors · 2023Article
- Onchocerciasis in the Ntui Health District of Cameroon: epidemiological, entomological and parasitological findings in relation to elimination prospects.Parasites & vectors · 2022Article
- Identification of the onchocerciasis vector in the Kakoi-Koda focus of the Democratic Republic of Congo.PLoS neglected tropical diseases · 2022Article
- A cross-sectional study of Simulium damnosum sensu lato breeding sites and species distribution in Sudan savanna, mixed savanna-forest and rainforest regions in Cameroon.Parasites & vectors · 2022Article
- Surveillance for Onchocerciasis-Associated Epilepsy and OV16 IgG4 Testing of Children 6-10 Years Old Should Be Used to Identify Areas Where Onchocerciasis Elimination Programs Need Strengthening.Pathogens (Basel, Switzerland) · 2022Article
Corrections and comments
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Authors and funding
15 authors at 7 institutions in 6 countries.
Funding
Abstract
backgroundThe onchocerciasis focus surrounding the lower Mbam and Sanaga rivers, where Onchocerca volvulus is transmitted by Simulium damnosum s.l. (Diptera: Simuliidae), was historically the largest in the southern regions of Cameroon. Annual community-directed treatment with ivermectin (CDTI) has been taking place since 2000, but recent studies have shown that new infections are occurring in children. We aimed to investigate blackfly biting and O. volvulus transmission rates along the lower Mbam river 16 years after the formal onset of annual CDTI.
methodsBlack flies were collected for three consecutive days each month between July 2016 and June 2017 at two riverside villages and two inland sites situated 4.9 km and 7.9 km from the riverside. Specimens collected at each site were dissected on one of the three collection days each month to estimate parity rates and O. volvulus infection rates, while the remaining samples were preserved for pool screening.
resultsIn total, 93,573 S. damnosum s.l. black flies were recorded biting humans and 9281 were dissected. Annual biting rates of up to 606,370 were estimated at the riverside, decreasing to 20,540 at 7.9 km, while, based on dissections, annual transmission potentials of up to 4488 were estimated at the riverside, decreasing to 102 and 0 at 4.9 km and 7.9 km, respectively. However, pool screening showed evidence of infection in black flies at the furthest distance from the river. Results of both methods demonstrated the percentage of infective flies to be relatively low (0.10-0.36%), but above the WHO threshold for interruption of transmission. In addition, a small number of larvae collected during the dry season revealed the presence of Simulium squamosum E. This is the first time S. squamosum E has been found east of Lake Volta in Ghana, but our material was chromosomally distinctive, and we call it S. squamosum E2.
conclusionsRelatively low O. volvulus infection rates appear to be offset by extremely high densities of biting black flies which are sustaining transmission along the banks of the lower Mbam river.
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