Large outbreak of Legionnaires' disease and Pontiac fever at a military base

Ambrose, John F; Hampton, Lee M.; Fleming-Dutra, Katherine E.; Marten, C.A.; McCLUSKY, C.; Perry, C. A.; Clemmons, Nakia; McCormic, Zachary D.; Peik, Samuel; Mancuso, James D.; Brown, Ellen; Kozak, Natalia A.; Travis, Tatiana; Lucas, Claressa E.; Fields, Barry S.; Hicks, Lauri A.; Cersovsky, Steven B.

doi:10.1017/s0950268813003440

Cited by 22 publications

(27 citation statements)

References 39 publications

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“…Old age, 23 smoking, 33 diabetes, 34 and COPD 23 are also among the most common comorbidities positively associated with legionellosis. Despite these risk factors, relatively healthy individuals are also commonly infected, 35 making the term “opportunistic pathogen” somewhat of a misnomer for Legionella .…”

Section: Introductionmentioning

confidence: 99%

Ten questions concerning the aerosolization and transmission of Legionella in the built environment

Prussin

Schwake

Marr

2017

Building and Environment

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Legionella is a genus of pathogenic Gram-negative bacteria responsible for a serious disease known as legionellosis, which is transmitted via inhalation of this pathogen in aerosol form. There are two forms of legionellosis: Legionnaires' disease, which causes pneumonia-like symptoms, and Pontiac fever, which causes influenza-like symptoms. Legionella can be aerosolized from various water sources in the built environment including showers, faucets, hot tubs/swimming pools, cooling towers, and fountains. Incidence of the disease is higher in the summertime, possibly because of increased use of cooling towers for air conditioning systems and differences in water chemistry when outdoor temperatures are higher. Although there have been decades of research related to Legionella transmission, many knowledge gaps remain. While conventional wisdom suggests that showering is an important source of exposure in buildings, existing measurements do not provide strong support for this idea. There has been limited research on the potential for Legionella transmission through heating, ventilation, and air conditioning (HVAC) systems. Epidemiological data suggest a large proportion of legionellosis cases go unreported, as most people who are infected do not seek medical attention. Additionally, controlled laboratory studies examining water-to-air transfer and source tracking are still needed. Herein, we discuss ten questions that spotlight current knowledge about Legionella transmission in the built environment, engineering controls that might prevent future disease outbreaks, and future research that is needed to advance understanding of transmission and control of legionellosis.

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Section: Introductionmentioning

confidence: 99%

Ten questions concerning the aerosolization and transmission of Legionella in the built environment

Prussin

Schwake

Marr

2017

Building and Environment

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“…Temperatures in the range of 20 °C to 45 °C together with stagnancy, sediment, sludge, scale, rust and microbial multispecies biofilms with protozoa within the water system provide favorable conditions for Legionella growing [1]. Free-living thermo-tolerant amoebae play a crucial role in the lifecycle of Legionella species as they provide a habitat for Legionella environmental survival and replication and also this intra-cel-nella transmission and cause either LD or Pontiac fever [6,10,14]. Reported legionellosis outbreaks with both LD and PF are relatively rare [10].…”

Section: Introductionmentioning

confidence: 99%

“…Free-living thermo-tolerant amoebae play a crucial role in the lifecycle of Legionella species as they provide a habitat for Legionella environmental survival and replication and also this intra-cel-nella transmission and cause either LD or Pontiac fever [6,10,14]. Reported legionellosis outbreaks with both LD and PF are relatively rare [10]. Virulence and viability of Legionellae, size of respirable particles and susceptibility of exposed people are decisive for disease development.…”

Section: Introductionmentioning

confidence: 99%

“…They include mostly open-circuit cooling towers that can range in size from small towers used in air conditioning to large towers for heavy industrial applications [15]. Aerosols generated from open cooling towers can through water droplets transmit legionellae over large distances to susceptible hosts [16] and cause legionellosis in community [10,14] as well as in hospitals [17]. It is imperative that CT are managed to prevent legionella colonization and the potential release of contaminated aerosols.…”

Section: Introductionmentioning

confidence: 99%

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Risk of Legionellosis from Exposure to Water Aerosol from Industrial Cooling Tower

Spaleková¹,

Kotrbancová²,

Fulová³

et al. 2019

Int Arch Public Health Community Med

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Background: Community-acquired cases of Legionella infection or even outbreaks can be attributed to inhalation of aerosols from devices such as hot water system, cooling towers, hot tubs, industrial equipment and indoor fountains. Legionellae survive in water in temperatures between 20 °C and 50 °C and tend to colonize particularly water systems rich of sludge, rust, biofilms and amoebae where they can multiply. Cooling towers (CT) in industry are used as heat-transfer devices in which warm water is cooled by evaporation in atmospheric air. Aerosols can transmit Legionellae to susceptible hosts, who can contract either Legionnaires´ disease (elderly with many risk factors) or Pontiac fever (young or middle-aged people relatively healthy without any risk factors). Aim: Aim of the study was risk assessment of legionellosis for workers in contact with contaminated water aerosol from industrial cooling towers. Methods: Water samples from industrial cooling towers and air samples were processed by standard manner (EN ISO 11731) and plated on special buffered charcoal yeast extract agar with 0.1% ketoglutarate and L-cysteine (BCYα medium) containing glycine, vancomycin, polymyxin B, cycloheximide (GVPC medium) for Legionella isolation. Exposure of workers to water aerosols was evaluated by interview, questionnaire, serological testing (agglutination test), cultivation of sputum on BMPA (BCYα medium with cefamandole, polymyxin B, anisomycin), detection of Legionella antigen in urine by ELISA and DNA Legionella in sera by PCR. Results: Sampling water from 6 cooling towers revealed isolates of Legionella pneumophila (L.p.) serogroups 1, 5, 10 from four of them (1,6 × 10 2-1,49 × 10 4 /200 ml). Investigation of air around three CT showed contamination by L. p. serogroup 12 in one of them. Antibodies only against this L. p. serogroup 12 were detected in single sera (1:128-1:256) in 13 workers, i.e. in two external workers working directly inside CT (diving) and 11 internal workers, who attended instruction meeting lasting several hours close to this tower. The workers contracted non-pneumonic infection-Pontiac fever with mild clinical symptoms. Conclusion: Exposure to water aerosols produced by the industrial cooling tower led to the cluster of non-pneumonic professional Legionella infection in workers. Results of the study were used for recommendation of repressive (disinfection, operating regimen of towers) and preventive (respiratory protective equipment, monitoring of Legionella colonization, etc.) measures.

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“…All species are found in the environment and about half of these can cause a life-threatening illness in humans. L. pneumophila is the major pathogen of this group and is further subdivided into 16 serogroups with the majority (80-84%) of legionellosis cases caused by Lp1 (Ambrose et al, 2014)(Kozak-Muiznieks et al, 2014)(Raphael et al, 2016). Since the first description of Legionnaires disease in 1976 when a large outbreak of pneumonia occurred at an American Legion conference in Philadelphia (Fraser et al, 1977), this infection has been implicated in multiple sporadic cases and community outbreaks globally, most commonly in males over 50, people with co-morbidities and smokers (Frieden, Jaffe, Stephens, & Thacker, 2011).…”

Section: Introductionmentioning

confidence: 99%

Genome sequencing links persistent outbreak of legionellosis in Sydney to an emerging clone ofLegionella pneumophilaST211

Timms

Rockett

Bachmann

et al. 2017

Preprint

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The city of Sydney, Australia, experienced a persistent outbreak of Legionella pneumophila serogroup 1 (Lp1) pneumonia in 2016. To elucidate the source and bring the outbreak to a close we examined the genomes of clinical and environmental Lp1 isolates recovered over 7 weeks. A total of 48 isolates from patients and cooling towers were sequenced and compared using SNP-based, core-genome MLST and pangenome approaches. All three methods confirmed phylogenetic relatedness between isolates associated with outbreaks in the Central Business District (March and May) and Suburb 1. These isolates were designated “Main cluster” and consisted of isolates from two patients from the CBD March outbreak, one patient and one tower isolate from Suburb 1 and isolates from two cooling towers and three patients from the CDB May outbreak. All main cluster isolates were sequence type ST211 which has only ever been reported in Canada. Significantly, pangenome analysis identified mobile genetic elements containing a unique T4ASS that was specific to the main cluster and co-circulating clinical strains, suggesting a potential mechanism for increased fitness and persistence of the outbreak clone. Genome sequencing was key in deciphering the environmental sources of infection among the spatially and temporally coinciding cases of legionellosis in this highly populated urban setting. Further, the discovery of a unique T4ASS emphasises the potential contribution of genome recombination in the emergence of successful Lp1 clones.

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Large outbreak of Legionnaires' disease and Pontiac fever at a military base

Cited by 22 publications

References 39 publications

Ten questions concerning the aerosolization and transmission of Legionella in the built environment

Ten questions concerning the aerosolization and transmission of Legionella in the built environment

Risk of Legionellosis from Exposure to Water Aerosol from Industrial Cooling Tower

Genome sequencing links persistent outbreak of legionellosis in Sydney to an emerging clone ofLegionella pneumophilaST211

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