Sustaining Lymphatic Filariasis Elimination: A Systematic Review of Post-Intervention and Post-Validation Challenges

Background:
The Global Programme to Eliminate Lymphatic Filariasis (GPELF) has made substantial progress, with 21 countries confirmed as having eliminated lymphatic filariasis (LF) as a public health problem and 14 under surveillance. However, sustaining elimination following mass drug administration (MDA) and during post-validation phases remains a major challenge. This review aimed to systematically identify and characterize challenges affecting the sustainability of LF elimination globally.

Methods:
A systematic review was conducted in accordance with the PRISMA guidelines. PubMed/MEDLINE, Europe PubMed Central, DOAJ, and Scopus were searched (July–October 2025) without time restrictions. Search terms combined LF-related keywords (e.g., lymphatic filariasis, Wuchereria bancrofti, Brugia malayi) with post-elimination concepts (e.g., post-MDA, surveillance, recrudescence) and challenges. Studies reporting challenges were included and categorized into biological, vector-related, socio-behavioural, and health system domains. Data were extracted and synthesized thematically.

Results:
Fourteen studies from eight countries met the inclusion criteria, spanning three WHO regions: African (57%), South-East Asia (36%), and Western Pacific (7%). Most studies evaluated post-intervention settings (79%). Biological challenges were most frequently reported (86%), including persistent microfilaremia and circulating filarial antigen (CFA) positivity following MDA cessation, suggesting ongoing transmission. Limited post-validation evidence indicated possible persistence, with CFA prevalence around 2.2% up to seven years after validation. Health system challenges (86%), particularly surveillance gaps and operational weaknesses, were also prominent. Socio-behavioural (50%) and vector-related (43%) factors further contributed to continued transmission risk.

Conclusion:
Sustained LF elimination is hindered by persistent infection reservoirs, surveillance gaps, and socio-behavioural barriers. Regional variation highlights the need for context-specific strategies. Strengthening surveillance and response systems is essential to prevent recrudescence and ensure long-term elimination.