Milan area Legionella outbreak: 53 cases and 4 deaths in few months

A note released by the Italian Institute of Health (ISS) indicates that a significant Legionellosis outbreak occurred in Milan between April and August 2024, with 53 cases reported by August 26. The mean age of patients was 71.7 years, and 48 (91%) had pre-existing risk factors. So far, 37 patients have been discharged from the hospital, 12 remain hospitalized, and 4 individuals, all over the age of 70 with preexisting medical conditions, have succumbed to their illnesses. The Milan Health Protection Agency (ATS) is conducting a thorough investigation that includes epidemiological, microbiological, and environmental studies to identify the source of infection and devise preventive strategies against further cases. This involves collecting samples from private homes and more than 80 potential risk sites, such as cooling towers in public and industrial buildings. Additionally, molecular typing of Legionella strains is underway to determine the bacterial spread mechanisms and pinpoint the infection’s origin.