A virologist and Director of the national OBEPINE+ platform (France 2030 / SGPI), Professor Maréchal leads a research network of 22 academic and industrial partners dedicated to the development of wastewater-based epidemiology, notably to deliver early-warning systems and epidemic surveillance tools. He is also the lead or co-lead of several research programs aimed at implementing wastewater epidemiology in resource-limited settings (the ATLANTES Project, supported by the Agence Française de Développement), improving early detection of respiratory infections (the SISP&Eau Project, France 2030, PEPR MIE), and monitoring sexually transmitted infections (the PapillEau Project, ANRS-MIE). These approaches, central to the “One Health” strategy, aim to support public-sector stakeholders in preventing infectious risks, particularly emerging zoonotic infectious diseases. This work aligns with strategies that place prevention within a global and transnational health framework.