Global Lymphatic Filariasis Post-Validation Surveillance Activities in 2025: A Scoping Review

Following World Health Organization (WHO) validation of lymphatic filariasis (LF) elimination as a public health problem, countries are required to implement post-validation surveillance (PVS) to detect potential resurgence and ensure sustained elimination. Despite WHO guidelines to implement at least two of four PVS strategies – targeted surveys, integration into standardised surveys, health facility-based screening, and molecular xenomonitoring (MX) – implementation varies widely. This review syn-thesised global evidence on PVS activities from 2007–2025 in the 23 countries and territo-ries validated as having eliminated LF. Studies were identified through PubMed, Scopus, Embase, Web of Science, and WHO Institutional Repository for Information Sharing (IRIS). Data on publication information, surveillance strategies, priority populations, and opera-tional challenges and enablers were extracted. Narrative synthesis using deductive con-tent analysis was applied. Thirty documents from 17 countries were included. Targeted surveillance and integration of PVS with other health programs were the most common approaches noted (reported in ten and nine countries respectively), followed by MX (seven countries) and health facility-based screening (four countries). Surveillance often focused on migrants and previous hotspots, with operational challenges linked to limited funding, workforce, and supply chains. Documents indicated that Sri Lanka, Thailand, China, and South Korea developed sustained PVS through national policies and domestic funding. Findings highlight the need for clear, contextualised guidance to operationalise sustaina-ble PVS in different settings.