The one health approach applied to surveillance and control of Legionnaires’ disease in Switzerland

ISSUE/PROBLEM: Legionnaires’ disease numbers have been increasing in Switzerland since 2001. With a reporting rate of 6.5 / 100'000 inhabitants in 2022, Switzerland has one of the highest incidences in Europe. The reported cases are mainly severe, about 87 % are diagnosed by hospitals, about 5 % have already died at the time of reporting. In the majority of cases the infection source is unknown. DESCRIPTION OF THE PROBLEM: Because the causative agent, Legionella spp., is ubiquitous in humid environments, including building plumbing systems, a collaborative, multisectoral and transdisciplinary approach is key for an efficient response to this public health threat. RESULTS: At the national level, a close collaboration between the federal offices for public health, food safety (public shower and bath water) and energy (buildings and energy) was established in 2019 with the creation of a dedicated legionellosis expert group. Goals were to strengthen the coordination and to improve measures to combat the observed increase. LESSONS: Stakeholders from authorities responsible for implementing measures but also building and sanitary experts, specialists in cooling technology, laboratory experts and scientists have been involved in multiple activities coordinated by the national legionellosis expert group. Together they revise recommendations for prevention and control of legionellosis, and develop factsheets for building technology engineers and an outbreak investigation toolbox. A coordinated communication to the public is ensured, for example in view of possible energy shortage measures. Knowledge gaps have been identified and scientific research to fill them is coordinated, mutually funded and the results will be transferred into practice in the coming years. KEY MESSAGES: • The One Health approach has proven to be very effective in coordination of activities and communication. • The future will reveal if the joint efforts will have an impact on the high incidence.