{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T11:12:36Z","timestamp":1789729956860,"version":"4.0.1"},"reference-count":27,"publisher":"Public Library of Science (PLoS)","issue":"8","license":[{"start":{"date-parts":[[2024,8,20]],"date-time":"2024-08-20T00:00:00Z","timestamp":1724112000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Coalition for Operational Research on Neglected Tropical Disesaes"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:sec id=\"sec001\">\n<jats:title>Background<\/jats:title>\n<jats:p>Lymphatic filariasis (LF), a mosquito-borne helminth infection, is an important cause of chronic disability globally. The World Health Organization has validated eight Pacific Island countries as having eliminated lymphatic filariasis (LF) as a public health problem, but there are limited data to support an evidence-based approach to post-validation surveillance (PVS). Tonga was validated as having eliminated LF in 2017 but no surveillance has been conducted since 2015. This paper describes a protocol for an operational research project investigating different PVS methods in Tonga to provide an evidence base for national and regional PVS strategies.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec002\">\n<jats:title>Methods<\/jats:title>\n<jats:p>Programmatic baseline surveys and Transmission Assessment Surveys conducted between 2000\u20132015 were reviewed to identify historically \u2018high-risk\u2019 and \u2018low-risk\u2019 schools and communities. \u2018High-risk\u2019 were those with LF antigen (Ag)-positive individuals recorded in more than one survey, whilst \u2018low-risk\u2019 were those with no recorded Ag-positives. The outcome measure for ongoing LF transmission will be Ag-positivity, diagnosed using Alere\u2122 Filariasis Test Strips. A targeted study will be conducted in May-July 2024 including: (i) high and low-risk schools and communities, (ii) boarding schools, and (iii) patients attending a chronic-disease clinic. We estimate a total sample size of 2,010 participants.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec003\">\n<jats:title>Conclusions<\/jats:title>\n<jats:p>Our methodology for targeted surveillance of suspected \u2018high-risk\u2019 populations using historical survey data can be adopted by countries when designing their PVS strategies. The results of this study will allow us to understand the current status of LF in Tonga and will be used to develop the next phase of activities.<\/jats:p>\n<\/jats:sec>","DOI":"10.1371\/journal.pone.0307331","type":"journal-article","created":{"date-parts":[[2024,8,20]],"date-time":"2024-08-20T18:08:30Z","timestamp":1724177310000},"page":"e0307331","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":13,"title":["Operational research to inform post-validation surveillance of lymphatic filariasis in Tonga study protocol: History of lymphatic filariasis elimination, rational, objectives, and design"],"prefix":"10.1371","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9699-8201","authenticated-orcid":true,"given":"Harriet","family":"Lawford","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"\u2018Ofa","family":"Tukia","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joseph","family":"Takai","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarah","family":"Sheridan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Colleen L.","family":"Lau","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2024,8,20]]},"reference":[{"issue":"5","key":"pone.0307331.ref001","doi-asserted-by":"crossref","first-page":"e0008289","DOI":"10.1371\/journal.pntd.0008289","article-title":"A systematic review of alternative surveillance approaches for lymphatic filariasis in low prevalence settings: Implications for post-validation settings.","volume":"14","author":"N Riches","year":"2020","journal-title":"PLoS Negl Trop Dis"},{"key":"pone.0307331.ref002","volume-title":"Human filariasis. 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