03033nas a2200289 4500000000100000008004100001260003700042653005700079653002400136100001100160700001100171700001100182700001300193700002200206700001300228700001600241700001300257700001400270700001200284700001400296245008400310856009900394300001300493490000700506520221600513022001402729 2020 d bPublic Library of Science (PLoS) 10 aPublic Health, Environmental and Occupational Health 10 aInfectious Diseases 1 aBah YM 1 aPaye J 1 aBah MS 1 aConteh A 1 aRedwood-Sawyerr V 1 aSonnie M 1 aVeinoglou A 1 aKoroma J 1 aHodges MH 1 aZhang Y 1 aTurner JD 00 aAchievements and challenges of lymphatic filariasis elimination in Sierra Leone uhttps://journals.plos.org/plosntds/article/file?id=10.1371/journal.pntd.0008877&type=printable ae0008877 0 v14 3 a
Background
Lymphatic filariasis (LF) is targeted for elimination in Sierra Leone. Epidemiological coverage of mass drug administration (MDA) with ivermectin and albendazole had been reported >65% in all 12 districts annually. Eight districts qualified to implement transmission assessment survey (TAS) in 2013 but were deferred until 2017 due to the Ebola outbreak (2014–2016). In 2017, four districts qualified for conducting a repeat pre-TAS after completing three more rounds of MDA and the final two districts were also eligible to implement a pre-TAS.
Methodology/Principal findings
For TAS, eight districts were surveyed as four evaluation units (EU). A school-based survey was conducted in children aged 6–7 years from 30 clusters per EU. For pre-TAS, one sentinel and one spot check site per district (with 2 spot check sites in Bombali) were selected and 300–350 persons aged 5 years and above were selected. For both surveys, finger prick blood samples were tested using the Filariasis Test Strips (FTS).
For TAS, 7,143 children aged 6–7 years were surveyed across four EUs, and positives were found in three EUs, all below the critical cut-off value for each EU. For the repeat pre-TAS/pre-TAS, 3,994 persons over five years of age were surveyed. The Western Area Urban had FTS prevalence of 0.7% in two sites and qualified for TAS, while other five districts had sites with antigenemia prevalence >2%: 9.1–25.9% in Bombali, 7.5–19.4% in Koinadugu, 6.1–2.9% in Kailahun, 1.3–2.3% in Kenema and 1.7% - 3.7% in Western Area Rural.
Conclusions/Significance
Eight districts in Sierra Leone have successfully passed TAS1 and stopped MDA, with one more district qualified for conducting TAS1, a significant progress towards LF elimination. However, great challenges exist in eliminating LF from the whole country with repeated failure of pre-TAS in border districts. Effort needs to be intensified to achieve LF elimination.
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