Niger: the first human onchocerciasis-endemic country in Africa to achieve elimination of infection transmission

BACKGROUND: Aerial larviciding of Simulium breeding sites in Niger was conducted from 1976 to 1989, as onchocerciasis was a serious public health problem. In 2002, onchocerciasis was declared no longer of public health importance. Surveys to determine whether transmission of infection was still occurring began in 2014, including onchocerciasis elimination mapping in 2019-2020. METHODS: The endemic area encompassed 1575 communities across the basins of the Niger, Tapoa, Goroubi, Diamangou, Sirba and Mekrou rivers. From 2014 to 2018, flies caught from 55 sites were processed to detect infection using a polymerase chain reaction protocol. In 2018, Ov16 antibody levels were assessed in children, following World Health Organization guidelines, in areas suspected of ongoing transmission. Confirmatory testing of blackflies and Ov16 serology and parasite loads in residents was also performed. RESULTS: Between 2014 and 2016, 161 641 blackflies from 17 sites, in the six river basins were examined (with 7 surveyed twice), and an additional 126 283 flies from 13 sites processed in 2018; no Onchocerca volvulus infective larvae were found. Thus, the official elimination threshold (