Reframing Leishmania 360° in the MISEV2023 Era: A Translational Framework for Extracellular Vesicle Biomarkers and One Health Implementation

Extracellular vesicles (EVs) mediate communication between Leishmania parasites and their hosts through the transfer of proteins, lipids and nucleic acids that influence immune responses, parasite persistence and disease progression. Despite more than a decade of investigation, translation of EV-associated discoveries into clinical, veterinary and public-health applications remains limited. Methodological heterogeneity, inconsistent reporting practices and insufficient validation continue to impede the development of clinically actionable biomarkers. Concurrently, the evolution from MISEV2018 to MISEV2023 reflects the broader maturation of extracellular-vesicle science, shifting the field from descriptive characterisation towards greater emphasis on reproducibility, functional validation and translational relevance. Here, we revisit the Leishmania 360° concept through the complementary lenses of MISEV2023, translational medicine and One Health. We argue that the principal challenge is no longer the identification of vesicular cargo, but the establishment of evidence-based frameworks capable of determining whether EV-associated signals are sufficiently validated to support clinical, veterinary or public-health decision-making. A central conceptual advance is the Dual-Compartment Liquid Biopsy Paradigm, whereby parasite-derived and host-response EVs are interpreted as complementary indicators of pathogen biology and host pathophysiology, providing a multidimensional framework for diagnosis, prognosis, treatment monitoring and surveillance. Building upon this concept, we introduce LEV-MISEV, a claim-to-evidence framework that extends MISEV2023 principles beyond methodological reporting by linking biological, clinical and public-health claims to proportional evidentiary requirements. We further propose a staged translational framework comprising the Translational Readiness Level for Extracellular Vesicles (TRL-EV) and the Leishmania 360° Translational Evidence Matrix. Whereas TRL-EV evaluates biomarker maturity along the pathway from discovery to implementation, the Translational Evidence Matrix assesses the overall strength of evidence across biological, analytical, clinical, operational and One Health domains. Together, these complementary frameworks identify translational bottlenecks, prioritise validation efforts and support evidence-based implementation planning. Finally, we position EV signatures as a molecular intelligence layer within climate-informed One Health surveillance systems integrating human, canine, vector and environmental data. Application of these frameworks indicates that no EV-based application in leishmaniasis has yet progressed beyond the stage of clinically associated biomarker candidates. We therefore propose a translational roadmap that integrates biological plausibility, analytical validity, clinical validity, implementation readiness and One Health utility. Collectively, these concepts reposition EVs not merely as sources of candidate biomarkers, but as components of a translational platform capable of supporting precision diagnostics, therapeutic monitoring, risk assessment and integrated surveillance. More broadly, the proposed framework may provide a transferable model for evidence-based biomarker development across infectious, parasitic and vector-borne diseases beyond leishmaniasis.