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Background: Onchocerciasis is endemic in 14 of Sierra Leone's 16 districts with high prevalence (47-88.5%) according to skin snips at baseline. After 11 rounds of mass treatment with ivermectin with good coverage, an impact assessment was conducted in 2017 to assess the progress towards eliminating onchocerciasis in the country., Methods: A cluster survey was conducted, either integrated with lymphatic filariasis (LF) transmission assessment survey (TAS) or standalone with the LF TAS sampling strategy in 12 (now 14) endemic districts. Finger prick blood samples of randomly selected children in Grades 1-4 were tested in the field using SD Bioline Onchocerciasis IgG4 rapid tests., Results: In total, 17,402 children aged 4-19 years in 177 schools were tested, and data from 17,364 children aged 4-14 years (14,230 children aged 5-9 years) were analyzed. Three hundred forty-six children were confirmed positive for Ov-16 IgG4 antibodies, a prevalence of 2.0% (95% CI 1.8-2.2%) in children aged 4-14 years with prevalence increasing with age. Prevalence in boys (2.4%; 95% CI 2.1-2.7%) was higher than in girls (1.6%; 95% CI 1.4-1.9%). There was a trend of continued reduction from baseline to 2010. Using data from children aged 5-9 years, overall prevalence was 1.7% (95% CI 1.5-1.9%). The site prevalence ranged from 0 to 33.3% (median prevalence = 0.0%): < 2% in 127 schools, 2 to < 5% in 34 schools and ≥ 5% in 16 schools. There was a significant difference in average prevalence between districts. Using spatial analysis, the Ov-16 IgG4 antibody prevalence was predicted to be < 2% in coastal areas and in large parts of Koinadugu, Bombali and Tonkolili Districts, while high prevalence (> 5%) was predicted in some focal areas, centered in Karene, Kailahun and Moyamba/Tonkolili., Conclusions: Low Ov-16 IgG4 antibody prevalence was shown in most areas across Sierra Leone. In particular, low seroprevalence in children aged 5-9 years suggests that the infection was reduced to a low level after 11 rounds of treatment intervention. Sierra Leone has made major progress towards elimination of onchocerciasis. However, attention must be paid to those high prevalence focal areas., (© 2024. The Author(s).)

Background: Preventive chemotherapy was administered to 3.2 million Sierra Leoneans in 13 health districts for lymphatic filariasis, onchocerciasis, and soil transmitted helminthes from October 2008 to February 2009. This paper aims to report the findings of a coverage survey conducted in 2009, compare the coverage survey findings with two reported rates for lymphatic filariasis coverage obtained using pre-mass drug administration (MDA) registration and national census projections, and use the comparison to understand the best source of population estimates in calculating coverage for NTD programming in Sierra Leone., Methodology/principal Findings: Community drug distributors (CDDs) conducted a pre- MDA registration of the population. Two coverage rates for MDA for lymphatic filariasis were subsequently calculated using the reported number treated divided by the total population from: 1) the pre-MDA register and 2) national census projections. A survey was conducted to validate reported coverage data. 11,602 persons participated (response rate of 76.8%). Overall, reported coverage data aggregated to the national level were not significantly different from surveyed coverage (z-test >0.05). However, estimates based on pre-MDA registration have higher agreement with surveyed coverage (mean Kendall's W = 0.68) than coverage calculated with census data (mean Kendall's = 0.59), especially in districts with known large-scale migration, except in a highly urban district where it was more challenging to conduct a pre-MDA registration appropriately. There was no significant difference between coverage among males versus females when the analyses were performed excluding those women who were pregnant at the time of MDA. The surveyed coverage estimate was near or below the minimum 65% epidemiological coverage target for lymphatic filariasis MDA in all districts., Conclusion/significance: These results from Sierra Leone illustrate the importance of choosing the right denominator for calculating treatment coverage for NTD programs. While routinely reported coverage results using national census data are often good enough for programmatic decision making, census projections can quickly become outdated where there is substantial migration, e.g. due to the impact of civil war, with changing economic opportunities, in urban settings, and where there are large migratory populations. In districts where this is known to be the case, well implemented pre-MDA registration can provide better population estimates. Pre-MDA registration should, however, be implemented correctly to reduce the risk of missing pockets of the population, especially in urban settings., Competing Interests: The authors have declared that no competing interests exist.

Background: Onchocerciasis is endemic in 12 of the 14 health districts of Sierra Leone. Good treatment coverage of community-directed treatment with ivermectin was achieved between 2005 and 2009 after the 11-year civil conflict. Sentinel site surveys were conducted in 2010 to evaluate the impact of five annual rounds of ivermectin distribution., Methods: In total, 39 sentinel villages from hyper- and meso-endemic areas across the 12 endemic districts were surveyed using skin snips in 2010. Results were analyzed and compared with the baseline data from the same 39 villages., Results: The average microfilaridermia (MF) prevalence across 39 sentinel villages was 53.10% at baseline. The MF prevalence was higher in older age groups, with the lowest in the age group of 1-9 years (11.00%) and the highest in the age group of 40-49 years (82.31%). Overall mean MF density among the positives was 28.87 microfilariae (mf)/snip, increasing with age with the lowest in the age group of 1-9 years and the highest in the age group of 40-49 years. Males had higher MF prevalence and density than females. In 2010 after five rounds of mass drug administration, the overall MF prevalence decreased by 60.26% from 53.10% to 21.10%; the overall mean MF density among the positives decreased by 71.29% from 28.87 mf/snip to 8.29 mf/snip; and the overall mean MF density among all persons examined decreased by 88.58% from 15.33 mf/snip to 1.75 mf/snip. Ten of 12 endemic districts had > 50% reduction in MF prevalence. Eleven of 12 districts had ≥50% reduction in mean MF density among the positives., Conclusions: A significant reduction of onchocerciasis MF prevalence and mean density was recorded in all 12 districts of Sierra Leone after five annual MDAs with effective treatment coverage. The results suggested that the onchocerciasis elimination programme in Sierra Leone was on course to reach the objective of eliminating onchocerciasis in the country by the year 2025. Annual MDA with ivermectin should continue in all 12 districts and further evaluations are needed across the country to assist the NTDP with programme decision making.

This article discusses the management of onchocerciasis, or river blindness, in Africa. The Onchocerciasis Control Programme in the Volta River Basin (OCP) was established in 1975 to combat the disease in seven West African countries. It later expanded to include four additional countries and changed its name to the Onchocerciasis Control Programme in West Africa (OCP). In 1995, the African Programme for Onchocerciasis Control (APOC) was launched to control the disease in all endemic countries in sub-Saharan Africa. APOC used community-directed treatment with ivermectin (CDTi) as its core strategy, leading to a significant decrease in infections and preventing millions of disability-adjusted life years (DALYs). The program also expanded its efforts to include other neglected tropical diseases (NTDs) susceptible to mass drug administration. APOC operates through a partnership between affected communities, governments, NGOs, and other stakeholders, with the World Health Organization (WHO) as the executing agency. APOC's success is attributed to its participative governance and engagement of communities through the CDTi strategy, empowering them to take responsibility for delivering treatment and expanding access to other health interventions. The document emphasizes the importance of community engagement, collaboration, and strengthening health systems at the community level in the planning, implementation, and monitoring of interventions for onchocerciasis control and other NTDs. The success [Extracted from the article]

Background: A baseline survey in 2007–2008 found lymphatic filariasis (LF) to be endemic in Sierra Leone in all 14 districts and co-endemic with onchocerciasis in 12 districts. Mass drug administration (MDA) with ivermectin started in 2006 for onchocerciasis and was modified to add albendazole in 2008 to include LF treatment. In 2011, after three effective MDAs, a significant reduction in microfilaraemia (mf) prevalence and density was reported at the midterm assessment. After five MDAs, in 2013, mf prevalence and density were again measured as part of a pre-transmission assessment survey (pre-TAS) conducted per WHO guidelines. Methods: For the pre-TAS survey, districts were paired to represent populations of one million for impact assessment. One sentinel site selected from baseline and one spot check site purposefully selected based upon local knowledge of patients with LF were surveyed per pair (two districts). At each site, 300 people over five years of age provided mid-night blood samples and mf prevalence and density were determined using thick blood film microscopy. Results are compared with baseline and midterm data. Results: At pre-TAS the overall mf prevalence was 0.54% (95% CI: 0.36–0.81%), compared to 0.30% (95% CI: 0.19–0.47) at midterm and 2.6% (95% CI: 2.3–3.0%) at baseline. There was a higher, but non-significant, mf prevalence among males vs females. Eight districts (four pairs) had a prevalence of mf < 1% at all sites. Two pairs (four districts) had a prevalence of mf > 1% at one of the two sites: Koinadugu 0.98% (95% CI: 0.34–2.85%) and Bombali 2.67% (95% CI: 1.41–5.00%), and Kailahun 1.56% (95% CI: 0.72–3.36%) and Kenema 0% (95% CI: 0.00–1.21%). Conclusions: Compared to baseline, there was a significant reduction of LF mf prevalence and density in the 12 districts co-endemic for LF and onchocerciasis after five annual LF MDAs. No statistically significant difference was seen in either measure compared to midterm. Eight of the 12 districts qualified for TAS. The other four districts that failed to qualify for TAS had historically high LF baseline prevalence and density and had regular cross-border movement of populations. These four districts needed to conduct two additional rounds of LF MDA before repeating the pre-TAS. The results showed that Sierra Leone continued to make progress towards the elimination of LF as a public health problem. [ABSTRACT FROM AUTHOR]