An all-you-can-eat restaurant in Chambéry is the very probable source of a Savoie Legionnaires' disease outbreak that killed two people and infected 48.
The Regional Health Agency and Santé publique France identified the establishment in the Landiers business park after discovering that 30 of the 48 recorded patients had eaten there prior to falling ill.
Health authorities confirmed that 46 people were hospitalised during the outbreak, which began on 1 June. The two fatalities were patients aged over 80.
Between 1 June and 21 August, 39 of the 48 infected individuals resided in western Savoie, primarily around the Chambéry basin. Savoie is a department located in the Auvergne-Rhône-Alpes region of southeastern France, where Chambéry serves as the prefectural capital.
Misting system suspected at buffet
Investigators focused on the restaurant after noting that its food buffets were fitted with a water misting system. Legionnaires' disease is a severe lung infection caused by Legionella bacteria, which spread when individuals inhale fine droplets of contaminated water spray.
Health officials asked the owner of the establishment, who was described by authorities as very cooperative, to shut down the misting device. Use of the system ended on 5 August, and no further cases have been reported among restaurant customers since that date.
Although environmental samples collected inside the restaurant failed to isolate the bacterium, authorities said multiple lines of evidence point to the site. Genetic analysis showed that four clinical strains isolated from affected diners were extremely close.
Patients also reported developing symptoms roughly seven days after dining at the restaurant, closely matching the standard six-day average incubation period for the disease. Health authorities believe private water networks account for the remaining quarter of the outbreak cases.
Public health response and disease transmission
Santé publique France and the Regional Health Agency led the weeks-long investigation to trace the source of the Savoy cluster. Legionnaires' disease typically causes pneumonia-like symptoms and poses the highest risk to older adults and individuals with underlying health conditions.
