Given worldwide advances in wastewater-based epidemiology (WBE), its implementation is also emerging in international sporting events. The WBE application to a major international sporting event held under winter and cold-climate conditions remains unexplored. The Milano-Cortina 2026 Winter Olympic and Paralympic Games, hosted in the Alpine region, provided a unique opportunity to explore the potential of wastewater surveillance during the winter period, when seasonal diseases also drive pathogen circulation. This paper presents the results of the WBE surveillance conducted in the Province of Trento, over six months (November 2025-April 2026) and covering the periods before, during, and after the Winter Olympic and Paralympic Games. A total of 96 wastewater samples were collected from six wastewater treatment plants (WWTPs) serving the Fiemme and Fassa valleys, with a total census population of about 29,000 but reaching 143,000 population equivalents during tourist periods. The WBE monitoring involved quantitative analyses of SARS-CoV-2, influenza A/B, RSV A/B, and Norovirus GI/GII, as well as screening for measles. Norovirus GI/GII and RSV A/B circulated as the number of event-related visitors increased, whereas SARS-CoV-2 and influenza viruses remained at background or seasonal levels. Clinical surveillance data in the Province of Trento effectively complemented this multi-pathogen WBE. In conclusion, this experience provided non-invasive, community-wide information and demonstrated the operational feasibility and usefulness of WBE as a multi-pathogen sentinel tool for situational awareness to complement public health surveillance.

Antimicrobial resistance (AMR) is increasingly recognized as an environmental issue, with wastewater treatment plants (WWTPs) acting both as receptors and potential dispersal points. This study compared a conventional activated sludge (CAS) and a membrane bioreactor (MBR, hollow-fiber, 0.04 µm) operating in parallel at a full-scale municipal WWTP (120,000 population equivalent, Trento, Italy), fed by the same primary-settled wastewater. Over six months, 24-h composite samples were collected at four points (raw influent, primary-settled wastewater, CAS effluent, MBR permeate) and analyzed by qPCR for six targets (16S rRNA, intI-1, qnrS, blaCTX-M, blaKPC, vanA) and by shotgun metagenomics. Primary settling had negligible impact on ARG abundance (0.05 log removal), whereas biological treatment achieved substantial reductions, with the MBR (3.3 logs, up to 4.9) significantly outperforming CAS (1.9 logs). Removal was gene-specific, highest for qnrS and blaCTX-M, and correlated with influent flow rate, mixed-liquor suspended solids, and organic matter. Metagenomics showed that the MBR reduced not only abundance but also the richness and diversity of bacteria and resistance genes, limiting their potential to spread further. These findings support MBR technology as a robust, though not absolute, barrier against AMR dissemination, pointing to the role that quaternary treatment could play in future wastewater management.