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The detection of a cluster of travel-associated Legionnaires’ disease (TALD) cases in any European Union/European Economic Area (EU/EEA) country prompts action at the accommodation, follow-up by health authorities and reporting of measures taken. Some accommodations incur further cases despite presumed implementation of adequate control measures.


To identify factors associated with the occurrence of a further TALD case after the implementation of control measures.


We conducted a retrospective cohort study of hotel and holiday rental accommodations in the EU/EEA associated with two or more TALD cases with onset dates less than 2 years apart (a ‘cluster’) and notification between 1 June 2011−31 December 2016. We fitted Cox regression models to estimate the association between accommodation characteristics and the occurrence of a further case, defined as any case with onset date after the report on measures taken.


Of the 357 accommodations in the analysis, 90 (25%) were associated with at least one further case after the report on measures taken (12.4/100 accommodation-years). Accommodations associated with two or more cases before the cluster notification were more likely to be associated with a further case, compared with those not previously associated with any case (adjusted hazard ratio 1.85; 95% confidence interval: 1.14–3.02). Neither the detection of in the water system nor the type of disinfection were found to be associated with the risk of a further case.


Accommodation size and previous TALD cases were predictive of further Legionnaires’ disease cases after implementation of control measures.


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  1. Fields BS, Benson RF, Besser RE. Legionella and Legionnaires’ disease: 25 years of investigation. Clin Microbiol Rev. 2002;15(3):506-26.  https://doi.org/10.1128/CMR.15.3.506-526.2002  PMID: 12097254 
  2. Correia AM, Ferreira JS, Borges V, Nunes A, Gomes B, Capucho R, et al. Probable Person-to-Person Transmission of Legionnaires’ Disease. N Engl J Med. 2016;374(5):497-8.  https://doi.org/10.1056/NEJMc1505356  PMID: 26840151 
  3. Beauté JThe European Legionnaires’ Disease Surveillance Network. Legionnaires’ disease in Europe, 2011 to 2015. Euro Surveill. 2017;22(27):30566.  https://doi.org/10.2807/1560-7917.ES.2017.22.27.30566  PMID: 28703097 
  4. Fraser DW, Tsai TR, Orenstein W, Parkin WE, Beecham HJ, Sharrar RG, et al. Legionnaires’ disease: description of an epidemic of pneumonia. N Engl J Med. 1977;297(22):1189-97.  https://doi.org/10.1056/NEJM197712012972201  PMID: 335244 
  5. Grist NR, Reid D, Najera R. Legionnaires’ disease and the traveller. Ann Intern Med. 1979;90(4):563-4.  https://doi.org/10.7326/0003-4819-90-4-563  PMID: 434635 
  6. Ricketts KD, Yadav R, Rota MC, Joseph CAEuropean Working Group for Legionella Infections. Characteristics of reoffending accommodation sites in Europe with clusters of Legionnaires disease, 2003-2007. Euro Surveill. 2010;15(40):19680.  https://doi.org/10.2807/ese.15.40.19680-en  PMID: 20946756 
  7. Phin N, Parry-Ford F, Harrison T, Stagg HR, Zhang N, Kumar K, et al. Epidemiology and clinical management of Legionnaires’ disease. Lancet Infect Dis. 2014;14(10):1011-21.  https://doi.org/10.1016/S1473-3099(14)70713-3  PMID: 24970283 
  8. Ricketts K, Joseph CEuropean Working Group for Legionella Infections. Travel-associated Legionnaires’ disease in Europe: 2003. Euro Surveill. 2004;9(10):480.  https://doi.org/10.2807/esm.09.10.00480-en  PMID: 15507729 
  9. European Centre for Disease Prevention Control (ECDC). Legionnaires' disease in Europe, 2011. ECDC surveillance report. Stockholm: ECDC; 2013.
  10. European Centre for Disease Prevention Control (ECDC). Legionnaires' disease in Europe, 2012. ECDC surveillance report. Stockholm: ECDC; 2014.
  11. European Centre for Disease Prevention Control (ECDC). Legionnaires' disease in Europe, 2013. ECDC surveillance report. Stockholm: ECDC; 2015.
  12. European Centre for Disease Prevention and Control (ECDC). Legionnaires' disease in Europe, 2014. ECDC surveillance report. Stockholm: ECDC; 2016.
  13. European Centre for Disease Prevention and Control (ECDC). Legionnaires' disease in Europe, 2015. ECDC surveillance report. Stockholm: ECDC; 2017.
  14. European Centre for Disease Prevention and Control (ECDC). European Legionnaires' Disease Surveillance Network (ELDSNet): operating procedures. ECDC technical document. Stockholm: ECDC; 2012.
  15. European Commission. 2012/506/EU: Commission Implementing Decision of 8 August 2012 amending Decision 2002/253/EC laying down case definitions for reporting communicable diseases to the Community network under Decision No 2119/98/EC of the European Parliament and of the Council. Official Journal of the European Union. Luxembourg: Publications Office of the European Union. 27.9.2012:L 262/1. Available from: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32012D0506
  16. Ricketts KD, Slaymaker E, Verlander NQ, Joseph CA. What is the probability of successive cases of Legionnaires’ disease occurring in European hotels? Int J Epidemiol. 2006;35(2):354-60.  https://doi.org/10.1093/ije/dyi317  PMID: 16434431 
  17. Bradburn MJ, Clark TG, Love SB, Altman DG. Survival analysis Part III: multivariate data analysis -- choosing a model and assessing its adequacy and fit. Br J Cancer. 2003;89(4):605-11.  https://doi.org/10.1038/sj.bjc.6601120  PMID: 12915864 
  18. Beauté J, Zucs P, de Jong B. Risk for travel-associated legionnaires’ disease, Europe, 2009. Emerg Infect Dis. 2012;18(11):1811-6.  https://doi.org/10.3201/eid1811.120496  PMID: 23092591 
  19. Vanaclocha H, Guiral S, Morera V, Calatayud MA, Castellanos M, Moya V, et al. Preliminary report: outbreak of Legionnaires disease in a hotel in Calp, Spain, update on 22 February 2012. Euro Surveill. 2012;17(8):20093. PMID: 22401506 
  20. Sánchez-Busó L, Guiral S, Crespi S, Moya V, Camaró ML, Olmos MP, et al. Genomic Investigation of a Legionellosis Outbreak in a Persistently Colonized Hotel. Front Microbiol. 2016;6:1556.  https://doi.org/10.3389/fmicb.2015.01556  PMID: 26834713 
  21. Mouchtouri V, Velonakis E, Hadjichristodoulou C. Thermal disinfection of hotels, hospitals, and athletic venues hot water distribution systems contaminated by Legionella species. Am J Infect Control. 2007;35(9):623-7.  https://doi.org/10.1016/j.ajic.2007.01.002  PMID: 17980243 
  22. Cervero-Aragó S, Rodríguez-Martínez S, Puertas-Bennasar A, Araujo RM. Effect of Common Drinking Water Disinfectants, Chlorine and Heat, on Free Legionella and Amoebae-Associated Legionella. PLoS One. 2015;10(8):e0134726.  https://doi.org/10.1371/journal.pone.0134726  PMID: 26241039 
  23. Rothman KJ, Greenland S, Lash TL. Modern epidemiology. 3rd ed. ed. Philadelphia: Lippincott Williams & Wilkins; 2008.
  24. Bonetta S, Bonetta S, Ferretti E, Balocco F, Carraro E. Evaluation of Legionella pneumophila contamination in Italian hotel water systems by quantitative real-time PCR and culture methods. J Appl Microbiol. 2010;108(5):1576-83.  https://doi.org/10.1111/j.1365-2672.2009.04553.x  PMID: 19796090 
  25. Doleans A, Aurell H, Reyrolle M, Lina G, Freney J, Vandenesch F, et al. Clinical and environmental distributions of Legionella strains in France are different. J Clin Microbiol. 2004;42(1):458-60.  https://doi.org/10.1128/JCM.42.1.458-460.2004  PMID: 14715805 
  26. Cowgill KD, Lucas CE, Benson RF, Chamany S, Brown EW, Fields BS, et al. Recurrence of legionnaires disease at a hotel in the United States Virgin Islands over a 20-year period. Clin Infect Dis. 2005;40(8):1205-7.  https://doi.org/10.1086/428844  PMID: 15791524 

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