Operational Performance of the Onchocerca volvulus OEPA Ov16 ELISA Serological Assay in Mapping, Guiding Decisions to Stop Mass Drug Administration, and Posttreatment Surveillance Surveys

Onchocerciasis is a neglected tropical disease targeted for elimination. The World Health Organization (WHO) has developed guidelines for the verification of onchocerciasis elimination that include entomological and epidemiological criteria. The latter require demonstrating with statistical confidence that the infection prevalence in children is less than 0.1%, necessitating an assay with a high degree of specificity. We present an analysis of the performance of the Onchocerciasis Elimination Program for the Americas (OEPA) version of the Ov16 enzyme-linked immunosorbant assay (ELISA) when used under operational conditions. In Africa and Latin America, the assay demonstrated 99.98% specificity in 69,888 children in 20 foci where transmission was believed to be interrupted. The assay produced a prevalence estimate equal to that of skin snip microscopy when applied in putatively hypo-endemic zones of Ethiopia. The OEPA Ov16 ELISA demonstratedthe specificity required to be effectively deployed to verify transmission elimination under the WHO guidelines, while exhibiting a sensitivity equivalent to skin snip microscopy to identify hypo-endemic areas.