Swimming pool-associated infectious disease outbreaks from 2020 to 2025: an updated literature review

Swimming pools and similar aquatic environments may harbour a range of microorganisms, including bacteria, viruses and protozoa capable of causing human disease. We conducted an updated literature review to characterise reported infectious disease outbreaks associated with swimming pools from 2020 onwards, with the aim of describing occurrence patterns and underlying causes across microbial groups. A systematic literature search covering the period 2020-2025 identified 872 publications, of which 23 peer-reviewed articles met the inclusion criteria for detailed analysis. Reported outbreaks remain frequent and are predominantly associated with operational and maintenance failures, particularly inadequate disinfection. Cryptosporidium and Legionella were the most frequently reported pathogens. These findings indicate that swimming pool-associated outbreaks continue to pose a public health concern. Strengthening operational management and integrating pathogen-specific control measures into comprehensive risk-based management frameworks may contribute to safer swimming pool environments.