Scientific article
Open access

Legionnaires' disease in Switzerland: rationale and study protocol of a prospective national case-control and molecular source attribution study (SwissLEGIO)

Published inInfection, vol. 51, no. 5, p. 1467-1479
Publication date2023-10
First online date2023-03-11

Switzerland has one of the highest annual Legionnaires' disease (LD) notification rates in Europe (7.8 cases/100,000 population in 2021). The main sources of infection and the cause for this high rate remain largely unknown. This hampers the implementation of targeted Legionella spp. control efforts. The SwissLEGIO national case-control and molecular source attribution study investigates risk factors and infection sources for community-acquired LD in Switzerland. Over the duration of one year, the study is recruiting 205 newly diagnosed LD patients through a network of 20 university and cantonal hospitals. Healthy controls matched for age, sex, and residence at district level are recruited from the general population. Risk factors for LD are assessed in questionnaire-based interviews. Clinical and environmental Legionella spp. isolates are compared using whole genome sequencing (WGS). Direct comparison of sero- and sequence types (ST), core genome multilocus sequencing types (cgMLST), and single nucleotide polymorphisms (SNPs) between clinical and environmental isolates are used to investigate the infection sources and the prevalence and virulence of different Legionella spp. strains detected across Switzerland. The SwissLEGIO study innovates in combining case-control and molecular typing approaches for source attribution on a national level outside an outbreak setting. The study provides a unique platform for national Legionellosis and Legionella research and is conducted in an inter- and transdisciplinary, co-production approach involving various national governmental and national research stakeholders.

  • Case–control study
  • Legionella spp
  • Legionnaires’ disease
  • Surveillance
  • Switzerland
  • Whole genome sequencing
  • Humans
  • Legionnaires' Disease / epidemiology
  • Legionnaires' Disease / diagnosis
  • Legionella pneumophila / genetics
  • Switzerland / epidemiology
  • Prospective Studies
  • Disease Outbreaks
  • Case-Control Studies
Citation (ISO format)
FISCHER, Fabienne et al. Legionnaires” disease in Switzerland: rationale and study protocol of a prospective national case-control and molecular source attribution study (SwissLEGIO). In: Infection, 2023, vol. 51, n° 5, p. 1467–1479. doi: 10.1007/s15010-023-02014-x
Main files (1)
Article (Published version)
ISSN of the journal0300-8126

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