Ongoing transmission of human onchocerciasis in blackflies in the medical district of Mont Ngafula 1 in Kinshasa after nearly two decades of uninterrupted onchocerciasis mass campaigns using community-directed treatment with ivermectin strategy.

Abstract

<h4>Introduction</h4>the medical district of Mont Ngafula 1 in Kinshasa, the capital city of the Democratic Republic of Congo (DRC), has been treated for onchocerciasis for over 16 years using Community-Directed Treatment with Ivermectin strategy (CDTI). This study aimed to determine blackfly infectivity rate and annual transmission potential in the Mont Ngafula medical district using O-150 PCR assay after four additional annual rounds of mass drug administration (MDA) following the initial entomological survey from August 2014 to July 2015.<h4>Methods</h4>this was a longitudinal entomological study. Blackflies were collected at the Kimwenza collection site in the Mont Ngafula medical district from 1^st August 2019 to 31^st July 2020 using the human landing collection technique. The WHO-recommended O-150 pool screening polymerase chain reaction assay was used to determine the blackfly infectivity rate and annual transmission potential.<h4>Results</h4>a cumulative 3,875 female blackflies were collected, and Simulium squamosum was identified as the main vector species. The infectivity rate was 0.75 % (95% CI: 0.48-1.13) with an annual transmission potential of 254 (95% CI: 153-396).<h4>Conclusion</h4>these findings confirm the persistent transmission of human onchocerciasis in the Mont Ngafula 1 medical district despite 16 years of ivermectin distribution using the Community-Directed Treatment with Ivermectin strategy. They highlight the urgent need for alternative treatment strategies to accelerate the interruption and elimination of onchocerciasis transmission.