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Yao XH, Shen F, Hao J, Huang L, Keng B. A review of Legionella transmission risk in built environments: sources, regulations, sampling, and detection. Front Public Health 2024; 12:1415157. [PMID: 39131570 PMCID: PMC11309999 DOI: 10.3389/fpubh.2024.1415157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 07/08/2024] [Indexed: 08/13/2024] Open
Abstract
The risk of Legionella transmission in built environments remains a significant concern. Legionella can spread within buildings through aerosol transmission, prompting the exploration of airborne transmission pathways and proposing corresponding prevention and control measures based on building characteristics. To this end, a comprehensive literature review on the transmission risk of Legionella in built environments was performed. Four electronic databases (PubMed, Web of Science, Google Scholar, and CNKI) were searched from inception to March 2024 for publications reporting the risk of Legionella transmission in built environments. Relevant articles and gray literature reports were hand-searched, and 96 studies were finally included. Legionella pollution comes from various sources, mainly originates in a variety of built environments in which human beings remain for extended periods. The sources, outbreaks, national standards, regulations, and monitoring techniques for Legionella in buildings are reviewed, in addition to increases in Legionella transmission risk due to poor maintenance of water systems and long-distance transmission events caused by aerosol characteristics. Air and water sampling using various analytical methods helps identify Legionella in the environment, recognize sources in the built environments, and control outbreaks. By comparing the standard regulations of national organizations globally, the authors further highlight gaps and deficiencies in Legionella surveillance in China. Such advancements offer essential insights and references for understanding and addressing Legionella transmission risk in the built environment, with the potential to contribute to safeguarding public health and building environment safety.
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Affiliation(s)
- Xiao Hui Yao
- Department of Environmental Health, Beijing Center for Disease Prevention and Control, Beijing, China
| | - Fan Shen
- Department of Environmental Health, Beijing Center for Disease Prevention and Control, Beijing, China
| | - Jing Hao
- Department of Environmental Health, Beijing Fengtai District Center for Disease Prevention and Control, Beijing, China
| | - Lu Huang
- Department of Environmental Health, Beijing Dongcheng District Center for Disease Prevention and Control, Beijing, China
| | - Bin Keng
- Department of Environmental Health, Beijing Huairou District Center for Disease Prevention and Control, Beijing, China
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Moffa MA, Rock C, Galiatsatos P, Gamage SD, Schwab KJ, Exum NG. Legionellosis on the rise: A scoping review of sporadic, community-acquired incidence in the United States. Epidemiol Infect 2023; 151:e133. [PMID: 37503568 PMCID: PMC10540183 DOI: 10.1017/s0950268823001206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 06/14/2023] [Accepted: 07/19/2023] [Indexed: 07/29/2023] Open
Abstract
Over the past two decades, the incidence of legionellosis has been steadily increasing in the United States though there is noclear explanation for the main factors driving the increase. While legionellosis is the leading cause of waterborne outbreaks in the US, most cases are sporadic and acquired in community settings where the environmental source is never identified. This scoping review aimed to summarise the drivers of infections in the USA and determine the magnitude of impact each potential driver may have. A total of 1,738 titles were screened, and 18 articles were identified that met the inclusion criteria. Strong evidence was found for precipitation as a major driver, and both temperature and relative humidity were found to be moderate drivers of incidence. Increased testing and improved diagnostic methods were classified as moderate drivers, and the ageing U.S. population was a minor driver of increasing incidence. Racial and socioeconomic inequities and water and housing infrastructure were found to be potential factors explaining the increasing incidence though they were largely understudied in the context of non-outbreak cases. Understanding the complex relationships between environmental, infrastructure, and population factors driving legionellosis incidence is important to optimise mitigation strategies and public policy.
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Affiliation(s)
- Michelle A. Moffa
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Clare Rock
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Hospital Epidemiology and Infection Control, Johns Hopkins Hospital, Baltimore, MD, USA
| | - Panagis Galiatsatos
- Medicine for the Greater Good, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shantini D. Gamage
- U.S. Department of Veterans Affairs, National Infectious Diseases Service, Veterans Health Administration, Washington, DC, USA
- Division of Infectious Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kellogg J. Schwab
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Natalie G. Exum
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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Pampaka D, Gómez-Barroso D, López-Perea N, Carmona R, Portero RC. Meteorological conditions and Legionnaires' disease sporadic cases-a systematic review. ENVIRONMENTAL RESEARCH 2022; 214:114080. [PMID: 35964674 DOI: 10.1016/j.envres.2022.114080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 07/29/2022] [Accepted: 08/05/2022] [Indexed: 06/15/2023]
Abstract
A number of studies suggest that meteorological conditions are related to the risk of Legionnaires' disease (LD) but the findings are not consistent. A systematic review was conducted to investigate the association of weather with sporadic LD and highlight the key meteorological conditions related to this outcome. PubMed, EMBASE, The Cochrane Library and OpenGrey were searched on 26-27 March 2020 without date, language or location restrictions. Key words included "legionellosis", "legionnaires' disease", combined with "meteorological conditions", "weather", "temperature", "humidity", "rain", "ultraviolet rays", "wind speed", etc. Studies were excluded if they did not examine the exposure of interest, the outcome of interest and their association or if they only reported LD outbreak cases. The study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and it was registered in PROSPERO (#CRD42020168869). There were 811 articles, of which 17 were included in the review. The studies investigated different meteorological variables and most of them examined the combined effect of several variables. The most commonly examined factors were precipitation and temperature, followed by relative humidity. The studies suggested that increased precipitation, temperature and relative humidity were positively associated with the incidence of LD. There was limited evidence that higher wind speed, pressure, visibility, UV radiation and longer sunshine duration were inversely linked with the occurrence of LD. A period of increased but not very high temperatures, followed by a period of increased precipitation, favour the occurrence of LD. Increased awareness of the association of temperature and precipitation and LD occurrence among clinicians and public health professionals can improve differential diagnosis for cases of sporadic community-acquired pneumonia and at the same time contribute to improving LD surveillance.
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Affiliation(s)
- Despina Pampaka
- National Centre of Epidemiology, Instituto de Salud Carlos III, Madrid, Spain; European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
| | - Diana Gómez-Barroso
- National Centre of Epidemiology, Instituto de Salud Carlos III, Madrid, Spain; CIBER Epidemiologia y Salud Publica, Instituto de Salud Carlos III, Madrid, Spain
| | - Noemí López-Perea
- National Centre of Epidemiology, Instituto de Salud Carlos III, Madrid, Spain; CIBER Epidemiologia y Salud Publica, Instituto de Salud Carlos III, Madrid, Spain
| | - Rocio Carmona
- National Centre of Epidemiology, Instituto de Salud Carlos III, Madrid, Spain
| | - Rosa Cano Portero
- National Centre of Epidemiology, Instituto de Salud Carlos III, Madrid, Spain; CIBER Epidemiologia y Salud Publica, Instituto de Salud Carlos III, Madrid, Spain
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Gamage SD, Jinadatha C, Coppin JD, Kralovic SM, Bender A, Ambrose M, Decker BK, DeVries AS, Goto M, Kowalskyj O, Maistros AL, Rizzo V, Simbartl LA, Watson RJ, Roselle GA. Factors That Affect Legionella Positivity in Healthcare Building Water Systems from a Large, National Environmental Surveillance Initiative. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:11363-11373. [PMID: 35929739 DOI: 10.1021/acs.est.2c02194] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Legionella growth in healthcare building water systems can result in legionellosis, making water management programs (WMPs) important for patient safety. However, knowledge is limited on Legionella prevalence in healthcare buildings. A dataset of quarterly water testing in Veterans Health Administration (VHA) healthcare buildings was used to examine national environmental Legionella prevalence from 2015 to 2018. Bayesian hierarchical logistic regression modeling assessed factors influencing Legionella positivity. The master dataset included 201,146 water samples from 814 buildings at 168 VHA campuses. Overall Legionella positivity over the 4 years decreased from 7.2 to 5.1%, with the odds of a Legionella-positive sample being 0.94 (0.90-0.97) times the odds of a positive sample in the previous quarter for the 16 quarters of the 4 year period. Positivity varied considerably more at the medical center campus level compared to regional levels or to the building level where controls are typically applied. We found higher odds of Legionella detection in older buildings (OR 0.92 [0.86-0.98] for each more recent decade of construction), in taller buildings (OR 1.20 [1.13-1.27] for each additional floor), in hot water samples (O.R. 1.21 [1.16-1.27]), and in samples with lower residual biocide concentrations. This comprehensive healthcare building review showed reduced Legionella detection in the VHA healthcare system over time. Insights into factors associated with Legionella positivity provide information for healthcare systems implementing WMPs and for organizations setting standards and regulations.
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Affiliation(s)
- Shantini D Gamage
- National Infectious Diseases Service, Specialty Care Program Office, Veterans Health Administration, Department of Veterans Affairs (VA), Washington, D.C. 20571, United States
- Division of Infectious Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, United States
| | - Chetan Jinadatha
- Department of Medicine, Central Texas Veterans Health Care System, Temple, Texas 76504, United States
- College of Medicine, Texas A&M University, Bryan, Texas 77807, United States
| | - John D Coppin
- Department of Research, Central Texas Veterans Health Care System, Temple, Texas 76504, United States
| | - Stephen M Kralovic
- National Infectious Diseases Service, Specialty Care Program Office, Veterans Health Administration, Department of Veterans Affairs (VA), Washington, D.C. 20571, United States
- Division of Infectious Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, United States
- Cincinnati VA Medical Center, Cincinnati, Ohio 45220, United States
| | - Alan Bender
- Booz Allen Hamilton, McLean, Virginia 22102, United States
| | - Meredith Ambrose
- National Infectious Diseases Service, Specialty Care Program Office, Veterans Health Administration, Department of Veterans Affairs (VA), Washington, D.C. 20571, United States
| | - Brooke K Decker
- Division of Infectious Diseases, VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania 15240, United States
| | - Aaron S DeVries
- Minneapolis VA Healthcare System, Minneapolis, Minnesota 55417, United States
| | - Michihiko Goto
- Iowa City VA Health Care System, Iowa City, Iowa 52246, United States
- University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, United States
| | - Oleh Kowalskyj
- Office of Healthcare Engineering, Healthcare Environment and Facilities Program, Veterans Health Administration, VA, Washington, D.C. 20571, United States
| | - Angela L Maistros
- VA Capitol Health Care Network, Veterans Integrated Service Network (VISN) 5, Linthicum, Maryland 21090, United States
| | - Vincent Rizzo
- Office of Healthcare Engineering, Healthcare Environment and Facilities Program, Veterans Health Administration, VA, Washington, D.C. 20571, United States
| | - Loretta A Simbartl
- National Infectious Diseases Service, Specialty Care Program Office, Veterans Health Administration, Department of Veterans Affairs (VA), Washington, D.C. 20571, United States
| | - Richard J Watson
- Occupational Health and Safety Program Office, Veterans Health Administration, VA, Washington, D.C. 20571, United States
| | - Gary A Roselle
- National Infectious Diseases Service, Specialty Care Program Office, Veterans Health Administration, Department of Veterans Affairs (VA), Washington, D.C. 20571, United States
- Division of Infectious Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, United States
- Cincinnati VA Medical Center, Cincinnati, Ohio 45220, United States
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Riccò M, Peruzzi S, Ranzieri S, Giuri PG. Epidemiology of Legionnaires' Disease in Italy, 2004-2019: A Summary of Available Evidence. Microorganisms 2021; 9:microorganisms9112180. [PMID: 34835307 PMCID: PMC8624895 DOI: 10.3390/microorganisms9112180] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/14/2021] [Accepted: 10/18/2021] [Indexed: 01/11/2023] Open
Abstract
Legionnaires’ disease (LD) incidence has been increasing in several European countries since 2011. Currently, Italy is experiencing high notification rates for LD, whose cause still remains scarcely understood. We sought to summarize the available evidence on the epidemiology of LD in Italy (2004–2019), characterizing the risk of LD by region, sex, age group, and settings of the case (i.e., community, healthcare, or travel-associated cases). Environmental factors (e.g., average air temperatures and relative humidity) were also included in a Poisson regression model in order to assess their potential role on the annual incidence of new LD cases. National surveillance data included a total of 23,554 LD cases occurring between 2004 and 2019 (70.4% of them were of male gender, 94.1% were aged 40 years and older), with age-adjusted incidence rates increasing from 1.053 cases per 100,000 in 2004 to 4.559 per 100,000 in 2019. The majority of incident cases came from northern Italy (43.2% from northwestern Italy, 25.6% from northeastern Italy). Of these, 5.9% were healthcare-related, and 21.1% were travel-associated. A case-fatality ratio of 5.2% was calculated for the whole of the assessed timeframe, with a pooled estimate for mortality of 0.122 events per 100,000 population per year. Poisson regression analysis was associated with conflicting results, as any increase in average air temperature resulted in reduced risk for LD cases (Incidence Rate Ratio [IRR] 0.807, 95% Confidence Interval [95% CI] 0.744–0.874), while higher annual income in older individuals was associated with an increased IRR (1.238, 95% CI 1.134–1.351). The relative differences in incidence between Italian regions could not be explained by demographic factors (i.e., age and sex distribution of the population), and also a critical reappraisal of environmental factors failed to substantiate both the varying incidence across the country and the decennial trend we were able to identify.
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Affiliation(s)
- Matteo Riccò
- Servizio di Prevenzione e Sicurezza Negli Ambienti di Lavoro (SPSAL), AUSL—IRCCS di Reggio Emilia, Via Amendola n.2, I-42022 Reggio Emilia, Italy
- Correspondence: or ; Tel.: +39-3392-994-343 or +39-522-837-587
| | - Simona Peruzzi
- Laboratorio Analisi Chimico Cliniche e Microbiologiche, Ospedale Civile di Guastalla, AUSL—IRCCS di Reggio Emilia, I-42016 Guastalla, Italy;
| | - Silvia Ranzieri
- Department of Medicine and Surgery, School of Occupational Medicine, University of Parma, Via Gramsci n.14, I-43123 Parma, Italy;
| | - Pasquale Gianluca Giuri
- Dipartimento Internistico Interaziendale, Struttura Operativa Semplice Dipartimentale “Medicina Infettivologica”, AUSL—IRCCS di Reggio Emilia, Ospedale “Sant’Anna”, I-42035 Castelnovo ne’ Monti, Italy;
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Effects of climate changes and road exposure on the rapidly rising legionellosis incidence rates in the United States. PLoS One 2021; 16:e0250364. [PMID: 33886659 PMCID: PMC8061983 DOI: 10.1371/journal.pone.0250364] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 03/30/2021] [Indexed: 11/27/2022] Open
Abstract
Legionellosis is an infection acquired through inhalation of aerosols that are contaminated with environmental bacteria Legionella spp. The bacteria require warm temperature for proliferation in bodies of water and moist soil. The legionellosis incidence in the United States has been rising rapidly in the past two decades without a clear explanation. In the meantime, the US has recorded consecutive years of above-norm temperature since 1997 and precipitation surplus since 2008. The present study analyzed the legionellosis incidence in the US during the 20-year period of 1999 to 2018 and correlated with concurrent temperature, precipitation, solar ultraviolet B (UVB) radiation, and vehicle mileage data. The age-adjusted legionellosis incidence rates rose exponentially from 0.40/100,000 in 1999 (with 1108 cases) to 2.69/100,000 in 2018 (with 9933 cases) at a calculated annual increase of 110%. In regression analyses, the rise correlated with an increase in vehicle miles driven and with temperature and precipitation levels that have been above the 1901–2000 mean since 1997 and 2008, respectively, suggesting more road exposure to traffic-generated aerosols and promotive effects of anomalous climate. Remarkably, the regressions with cumulative anomalies of temperature and precipitation were robust (R2 ≥ 0.9145, P ≤ 4.7E-11), implying possible changes to microbial ecology in the terrestrial and aquatic environments. An interactive synergy between annual precipitation and vehicle miles was also found in multiple regressions. Meanwhile, the bactericidal UVB radiation has been decreasing, which also contributed to the rising incidence in an inverse correlation. The 2018 legionellosis incidence peak corresponded to cumulative effects of the climate anomalies, vast vehicle miles (3,240 billion miles, 15904 km per capita), record high precipitation (880.1 mm), near record low UVB radiation (7488 kJ/m2), and continued above-norm temperature (11.96°C). These effects were examined and demonstrated in California, Florida, New Jersey, Ohio, and Wisconsin, states that represent diverse incidence rates and climates. The incidence and above-norm temperature both rose most in cold Wisconsin. These results suggest that warming temperature and precipitation surplus have likely elevated the density of Legionella bacteria in the environment, and together with road exposure explain the rapidly rising incidence of legionellosis in the United States. These trends are expected to continue, warranting further research and efforts to prevent infection.
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Brigmon RL, Turick CE, Knox AS, Burckhalter CE. The Impact of Storms on Legionella pneumophila in Cooling Tower Water, Implications for Human Health. Front Microbiol 2020; 11:543589. [PMID: 33362725 PMCID: PMC7758282 DOI: 10.3389/fmicb.2020.543589] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 11/02/2020] [Indexed: 12/03/2022] Open
Abstract
At the U.S. Department of Energy’s Savannah River Site (SRS) in Aiken, SC, cooling tower water is routinely monitored for Legionella pneumophila concentrations using a direct fluorescent antibody (DFA) technique. Historically, 25–30 operating SRS cooling towers have varying concentrations of Legionella in all seasons of the year, with patterns that are unpredictable. Legionellosis, or Legionnaires’ disease (LD), is a pneumonia caused by Legionella bacteria that thrive both in man-made water distribution systems and natural surface waters including lakes, streams, and wet soil. Legionnaires’ disease is typically contracted by inhaling L. pneumophila, most often in aerosolized mists that contain the bacteria. At the SRS, L. pneumophila is typically found in cooling towers ranging from non-detectable up to 108 cells/L in cooling tower water systems. Extreme weather conditions contributed to elevations in L. pneumophila to 107–108 cells/L in SRS cooling tower water systems in July–August 2017. L. pneumophila concentrations in Cooling Tower 785-A/2A located in SRS A-Area, stayed in the 108 cells/L range despite biocide addition. During this time, other SRS cooling towers did not demonstrate this L. pneumophila increase. No significant difference was observed in the mean L. pneumophila mean concentrations for the towers (p < 0.05). There was a significant variance observed in the 285-2A/A Tower L. pneumophila results (p < 0.05). Looking to see if we could find “effects” led to model development by analyzing 13 months of water chemistry and microbial data for the main factors influencing the L. pneumophila concentrations in five cooling towers for this year. It indicated chlorine and dissolved oxygen had a significant impact (p < 0.0002) on cooling tower 785A/2A. Thus, while the variation in the log count data for the A-area tower is statistically greater than that of the other four towers, the average of the log count data for the A-Area tower was in line with that of the other towers. It was also observed that the location of 785A/2A and basin resulted in more debris entering the system during storm events. Our results suggest that future analyses should evaluate the impact of environmental conditions and cooling tower design on L. pneumophila water concentrations and human health.
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Affiliation(s)
- Robin L Brigmon
- Savannah River National Laboratory, Environmental Science and Biotechnology Group, Aiken, SC, United States
| | - Charles E Turick
- Savannah River National Laboratory, Environmental Science and Biotechnology Group, Aiken, SC, United States
| | - Anna S Knox
- Savannah River National Laboratory, Environmental Science and Biotechnology Group, Aiken, SC, United States
| | - Courtney E Burckhalter
- Savannah River National Laboratory, Environmental Science and Biotechnology Group, Aiken, SC, United States
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