Evidence map›Paper›PMID 41996520›Full record

ArticlePloS one2026

Diagnostic testing intensity for Legionnaires' disease: Spatio-temporal assessment and its effect on surveillance case reporting, Denmark, 2014-2022.

Emmanuel Robesyn, Søren Anker Uldum, Karsten Dalsgaard Bjerre, Charlotte Kjelsø, Marc Struelens, Cecilia Stålsby Lundborg, Steen Ethelberg, Christel Faes

Abstract read
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Article in PloS one, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

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1citing papers in PubMed
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1 · What the graph read from it

What it found

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2 · The registry

The trial behind it

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3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

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4 · The record

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PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

Emmanuel RobesynDepartment of Global Public Health, Karolinska Institutet, Stockholm, Sweden.ORCID https://orcid.org/0000-0002-7487-9439
Søren Anker UldumESCMID Study Group for Legionella Infections (ESGLI), Basel, Switzerland.
Karsten Dalsgaard BjerreDepartment of Data Integration and Analysis, Statens Serum Institut, Copenhagen, Denmark.
Charlotte KjelsøDepartment of Infection Epidemiology and Prevention, Statens Serum Institut, Copenhagen, Denmark.
Marc StruelensFaculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium.
Cecilia Stålsby LundborgDepartment of Global Public Health, Karolinska Institutet, Stockholm, Sweden.ORCID https://orcid.org/0000-0001-6525-1861
Steen EthelbergDepartment of Infection Epidemiology and Prevention, Statens Serum Institut, Copenhagen, Denmark.ORCID https://orcid.org/0000-0002-9709-356X
Christel FaesData Science Institute, I-Biostat, Hasselt University, Hasselt, Belgium.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundThe global, national and subnational geographical and temporal distribution of reported Legionnaires' disease is extremely heterogeneous, and it is unknown to what extent this accurately reflects the variation in true disease incidence. We studied how diagnostic testing intensity varied across Danish municipalities between 2014 and 2022, how it influenced epidemiological surveillance, and how testing-adjusted reporting can be used to improve the study of disease incidence and its determinants. METHODS AND

findingsWe used data from the clinical Danish Microbiology Database and the Epidemiological Surveillance System and considered a tentative causal model of how Legionella infections give rise to the observed Legionnaires' disease surveillance data. We fitted spatio-temporal models using an approximate Bayesian inference for latent Gaussian models (INLA), providing probabilistic estimates. These allowed us to identify areas of increased risk and spatio-temporal interaction. Our assessment of the Legionnaires' disease testing intensity in Denmark showed considerable spatio-temporal variation across the country. The estimated municipal annual testing intensity ranged from 128 to 2,446 persons receiving at least one Legionella urinary antigen or PCR test per 100,000 inhabitants. The median increased between 2014 and 2022 steadily from 275 to 620 tested persons per 100,000 inhabitants, reflecting an upward trend. The proportion of tested persons with age over 70 increased from 44.8% to 56.4%. Increasing testing intensity leads to higher case reporting, until testing intensity reaches approximately 1000-1200 tested persons per 100 000 inhabitants. The estimated municipal annual testing-adjusted case reporting ranged from 1.4 to 12.0 per 100 000 inhabitants. The median fluctuated over the study period between 2.5 (range 1.4-6.2) in 2014 and 5.2 (range 1.5-11.7) in 2022 with a flat overall time effect.

conclusionsWe obtained estimates of the spatio-temporal variation of Legionnaires' disease among Danish municipalities. We quantified the positive effect of testing intensity on Legionnaires' disease reporting and found a threshold of annually testing slightly over 1% of the population above which the yield of new cases does not further increase. Despite limitations and possible bias, our study of testing-adjusted case reporting suggests that no substantial increase in Legionnaires' disease has occurred over the nine-year study period. Instead, case ascertainment by physicians has improved considerably through increased Legionella testing, particularly in elderly patients. Insight in the variation of testing intensity and its effect on Legionnaires' disease reporting can be used to improve guidance for Legionnaires' disease diagnosis, to better study determinants of Legionnaires' disease, and ultimately to improve Legionnaires' disease prevention and control.

Indexed as

Legionnaires' DiseaseAdolescentAdultAgedAged, 80 and overBayes TheoremChildChild, PreschoolDenmarkFemaleHumansIncidenceMaleMiddle AgedPopulation SurveillanceSpatio-Temporal Analysis

Identifiers

PMID41996520
PMCPMC13089883

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.