Strengthening lymphatic filariasis elimination programmes with molecular xenomonitoring: critical utility and unmet operational needs

Molecular xenomonitoring (MX)-the detection of filarial DNA in mosquito vectors-has become an important component of post- mass drug administration surveillance within the Global Programme to Eliminate Lymphatic Filariasis (GPELF). MX offers non-invasive, high-sensitivity detection of residual or recrudescent Wuchereria bancrofti transmission, particularly where human microfilaraemia and antigenemia surveys have limited power. However, the current operational model relies heavily on gravid-trap-based sampling, which captures a physiologically narrow, behaviourally biased subset of mosquitoes, often dominated by zoophagic Culex quinquefasciatus. This restricts interpretation and programme decision-making. We propose a restructured MX approach focused on representative multi-physiological sampling, routine blood-meal profiling, stage-specific molecular assays and harmonized analytical frameworks. With these refinements, MX can evolve into an actionable transmission-intelligence platform vital for sustaining lymphatic filariasis elimination in the endgame phase.