Field test and sensitivity of Onchocerciasis rapid test in Ogun State, Nigeria

Objective: This study, conducted between March 2015 and July 2016, investigated the sensitivity and specificity of the OV-16 RDT and Dried Blood Spot (DBS) Enzyme-Linked Immunosorbent Assay (ELISA) for skin snip microfilaria (MF) detection in Ogun State.

Methods: Five hundred and eighty-eight (588) members of 16 first-line communities in 8 endemic Local Government Areas (LGAs) provided fingerstick whole blood specimens examined for IgG4 antibodies against the O. volvulus antigen OV-16, using DBS OV-16 ELISA and OV-16 RDT. In consort with these specimens, 162 study participants consented to be evaluated by skin snip.

Results: Results showed a seroprevalence of 106(18.0%) using ELISA and 102(17.3%) by RDT, with 92.2% agreement. The OV-16 RDT demonstrated a positive and negative agreement of 76.4 (95% CI 67.2 to 84.1%) and 95.6% (95% CI: 93.4 to 97.3), respectively, to the OV-16 ELISA results from the concordant dataset. Against the 64 positive skin snips microscopy results, sensitivity of the RDT was 79.7% (95% CI 73.43% to 85.27) and the ELISA was 70.3% (95% CI 64.72% to 75.37%).

Conclusion: The results of this study provided information on the performance of the OV-16 RDT. This information will contribute data for comparison to studies in other areas where treatment is ongoing. In conclusion, the commercial launch of the OV-16 RDT has made available a point-of-care diagnostic tool that could serve to help local and country onchocerciasis elimination programs to measure changes and progress in onchocerciasis intervention.