Key Points

This Public Health Bulletin (BSP) presents a regional overview of the surveillance of waterborne acute gastroenteritis for the period from January 2010 to December 2021. These analyses are produced at the national level and across all regions based on indicators derived from health insurance data and information collected regionally as part of health and environmental investigations conducted by the Regional Health Agencies (ARS).

• Surveillance of waterborne acute gastroenteritis outbreaks

  • A unique nationwide multi-source surveillance system led by Santé publique France in collaboration with the Directorate General for Health and the Regional Health Agencies, designed to:

    • provide epidemiological indicators (signals of clusters of acute gastroenteritis cases) related to the infectious risk associated with the consumption of tap water;

    • improve understanding of the health impact of these events;

    • target measures to secure and control water distribution systems against infectious risks

  • Enabling the identification of water distribution units involved in clusters of acute gastroenteritis and the circumstances under which contamination entered the network;

  • Operational nationwide since March 2019, with retrospective data analysis dating back to 2010.

• Study periods for this BSP:

  • From January 2010 to December 2021 for all detected signals

  • Particular focus on the period from 2019 to 2021, corresponding to the prospective implementation period of the system

• Key data for Provence-Alpes-Côte d’Azur (January 2010 to December 2021, data as of 02/07/2023)

  • 533 statistical signals detected during the 2010–2021 period corresponding to clusters of cases of acute gastroenteritis with a plausible waterborne origin, including:

    • 168 alerts with epidemiological characteristics particularly consistent with the hypothesis of a waterborne outbreak, including 34 since early 2019;

    • 88 signals considered a priority for environmental investigations due to drinking water distribution units repeatedly implicated in multiple signals (86 units);

  • 20 investigated reports confirming an environmental origin for 16 outbreaks (including 11 since 2019):

    • 95% of investigated reports were waterborne (positive predictive value of the system);

    • The likelihood of a waterborne origin was rated as high for 9 reports (45%), probable for 2 (10%), and possible for 9 (45%).