03230nas a2200277   4500000000100000008004100001260003700042100001600079700001200095700001200107700001100119700001600130700001500146700001200161700001500173700001100188700001400199700001500213700001500228245016900243856009900412300000900511490000700520520241100527022001402938       2024                            d  bPublic Library of Science (PLoS)1 aNikièma AS1 aKoala L1 aPost RJ1 aKima A1 aCompaoré J1 aKafando CM1 aNana JB1 aBougouma C1 aFaye B1 aTraoré S1 aDabiré RK1 aFischer PU00aProgress towards elimination of onchocerciasis in the Region du Sud-Ouest of Burkina Faso which was previously subject to a recrudescence event after vector control  uhttps://journals.plos.org/plosntds/article/file?id=10.1371/journal.pntd.0012118&type=printable  a1-170 v183 a<p><strong>Background:&nbsp;</strong>The Sud-Ouest region of Burkina Faso (especially the Bougouriba valley) has been historically problematic with respect to onchocerciasis control, with a recrudescence of infections after vector control carried out the WHO Onchocerciasis Control Programme was halted in 1989. After 1996, mass drug administration of ivermectin was instigated to control the recrudescence so that it would no longer constitute a public health problem. However, in 2010 WHO changed its recommended policy from control to elimination, and in 2013 biannual Community-Directed Treatment with Ivermectin (CDTI) was instigated. Epidemiological surveys were carried-out in 2011 and 2018 to determine whether CDTI was producing a decline in infection levels and progress towards elimination.</p>

<p><strong>Methodology/Principal findings:</strong> A cross-sectional study was conducted across 20 villages in four health districts in 2011 and 29 villages in 2018. Individuals aged five years and above were examined by skin-snip, and the prevalence and microfilarial load was determined for each village. In 2011, 75% of villages had some infections and 20% had prevalences &gt;5%, with a mean prevalence across all villages of 2.63% (range 0.0–9.7%), and community microfilarial load ranging from 0 to 0.25 microfilariae per biopsy. In 2018, nine villages (= 31% of total) had some infections, with prevalences ranging from 0.41% to 3.54%, and a mean prevalence across all villages of 0.37%. Community microfilarial load ranged from 0 to 0.1. Amongst those people found to be microfilarial positive, 87% had a history of migration.</p>

<p><strong>Conclusions/significance:</strong> The endemicity of onchocerciasis infection in the Sud-Ouest region has declined to low levels and seems to be progressing towards elimination. Our findings indicated that biannual CDTI is having good effect, but it should continue for a number of years to ensure elimination of transmission. However, progress towards elimination has a troublesome history in this region, and it would be advisable to select more sentinel villages to have confidence in any future epidemiological and entomological surveys, especially Stop-MDA surveys. With positive individuals migrating between countries, cross-border collaboration needs more attention to ensure effective treatment for onchocerciasis elimination.</p>
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