The pervasive socio-economic and psychological burden of onchocerciasis in endemic communities of Bo District, Sierra Leone: an explanatory sequential mixed-methods study

Background Onchocerciasis (river blindness) persists in Bo District, Sierra Leone, despite decades of ivermectin-based mass drug administration (MDA). Programmatic efforts have prioritized parasitological and ocular outcomes, so the socio-economic and psychological burden of the disease within affected communities remains poorly quantified. We aimed to determine the magnitude, structure and distribution of this non-clinical burden. Methods We used an explanatory sequential mixed-methods design (QUAN → qual). In the quantitative phase, 1,500 adults across five endemic chiefdoms of Bo District (Bagbwe, Baoma, Gbo, Selenga, Tikonko) were surveyed using multistage cluster sampling. Socio-economic impact (range 0–2) and psychological impact (range 0–3) were each measured with a formative composite index summing binary items on economic hardship, education/employment obstacles, emotional well-being, social stigma, and self-esteem. Instruments were forward- and back-translated into Mende, pilot-tested (Cronbach’s α = 0.76–0.81), and administered on Android tablets using ODK Collect. We used chi-square tests, one-way ANOVA, independent-samples t-tests and Spearman correlation in JASP (v0.18). Eleven key informant interviews and eight focus group discussions (five participants each, n = 40) were analysed thematically to explain the quantitative findings. Ethical approval was granted by the Njala University Institutional Review Board (NUIRB) on 14 April 2024. Results The burden was extensive: 71.7% (95% CI 69.4–74.0) of respondents reported economic hardship and 95.8% (95% CI 94.7–96.7) scored at least one psychological impact. The socio-economic and psychological indices were statistically independent (ρ = .026, p = .311) and did not differ significantly across chiefdoms ( F (4,1495) = 1.91, p = .106), sexes (t(1498) = 0.26, p = .796), or age groups ( F (2,1497) = 0.80, p = .451). Qualitative themes described a productivity-poverty cycle, stigma experienced as “social death,” and an unrecognized gendered caregiving load. Conclusions Onchocerciasis imposes a pervasive, uniformly distributed dual burden in Bo District that is invisible to parasitological surveillance. Morbidity-management, stigma-reduction and psychosocial support should be delivered population-wide and integrated into primary healthcare and MDA delivery rather than targeted narrowly at demographic risk groups.