Usability, acceptability and cost of the SD BIOLINE Ov16 rapid diagnostic test for onchocerciasis surveillance in endemic communities in the middle belt of Ghana

BackgroundPrevious studies in the Bono Region (middle belt) of Ghana have reported persistent Onchocerca volvulus infection and associated morbidities after nearly three decades of ivermectin treatment. This study aimed to assess the usability, acceptability and cost of the Ov16 SD BIOLINE rapid diagnostic test (Ov16 RDT) in onchocerciasis surveillance activities in the middle belt of Ghana. MethodologyA cross-sectional study was conducted in 6 endemic communities in the Tain District and Wenchi Municipality. A total of 254 individuals (54% females; median age (range)=31 (5-83) years), agreed to participate in Ov16 RDT (100%), skin-snip microscopy (37%) and nodule palpation (100%). Post-test interviews were conducted for all 94 participants tested by all three diagnostics. A cost analysis based on testing 400 people was performed. Principal findingsOv16 seroprevalence was 23.6% (60/254, 95%CI=18.8%-29.2%); microfilarial prevalence 11.7% (11/94, 95%CI = 6.7%-19.8%) and nodule prevalence 5.5% (14/254, 95%CI=3.3%-9.0%). The proportion of Ov16 seropositive females (43/136, 31.6%) was twice that of males (17/117, 14.5%). Among 5-9-year-olds, Ov16 seroprevalence was 11.1% (3/27), microfilarial prevalence 23.1% (3/13) and nodule prevalence 3.7% (1/27). For the 94 participants with all three tests, there was no association between the results of Ov16 RDT, skin-snip microscopy and/or nodule palpation. Most participants and technicians preferred Ov16 RDT because of being less painful and invasive, easier to use and faster. Had 400 participants been tested, the total cost per individual would be US$24 (Ov16 RDT) and US$74 (skin-snip microscopy). ConclusionsOv16 RDT is more acceptable and affordable (a third of the cost) compared to skin-snipping for surveillance activities in transmission hotspots in Ghana. Author summaryOnchocerciasis (River blindness) is a neglected tropical disease targeted by the World Health Organization for elimination of transmission in 12 endemic countries by 2030. There is a need for field-friendly, acceptable and affordable tools to monitor progress towards elimination. In Ghana, the SD BIOLINE Ov16 rapid diagnostic test (Ov16 RDT) has been used in several epidemiological surveys, but its usability, acceptability and cost have not been assessed. We studied 6 endemic communities with persistent infection after nearly three decades of ivermectin treatment. The prevalence of seropositivity by Ov16 RDT was twice the prevalence of skin-snip microscopy positivity and four times the prevalence of nodule-palpation positivity. For the individuals tested by all three diagnostics, we found no agreement between the results of Ov16 RDT and skin-snip microscopy (and/or nodule palpation), likely owing to the long-term treatment in the study area. The Ov 16 RDT was acceptable to both study participants and technicians because it was less painful and invasive, and yielded results more quickly. The cost of skin-snip microscopy would be thrice that of Ov16 RDT when testing 400 individuals. Ov16 RDT is more acceptable and less costly than skin-snipping for surveillance activities in transmission hotspots in Ghana.