LEGIONELLA - World Health Organization

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Box . Potent al sources of leg onellae to be nvest gated n a system assessment Hotels Potential sources of legionellae in hotels include: • hot and cold-water storage tanks • shower heads • taps • toilet cisterns • hot tubs and swimming pools (both cold water and heated pools) • cooling towers • air-conditioning humidifiers • condensation trays in air-conditioners and fan coils • evaporative coolers • fire-fighting systems • irrigation systems • ornamental fountains • food humidifiers. Sh ps Potential sources of legionellae in ships include: • humidifiers (including food display units) • stagnant areas of pipework • air-conditioning (suspected) and handling units • regions on the ship with higher ambient temperatures on board than on shore • the general complexity of onboard water storage and distribution systems. Source: Atlas (1999) 7.3.2 Assess hazards and prioritize risks This step involves collecting and evaluating information on hazards and conditions leading to their presence, to decide which are significant for safety and therefore should be addressed in a safety plan. A survey conducted in the United Kingdom showed that legionellae were more likely to be found in hotels that had a large number of supply tanks and hot-water outlets, a high-capacity calorifier, and piping made of a metal other than copper (Bartlett et al., 1985). In general, this situation is what would be expected from our knowledge of the ecology of Legionella (discussed in Chapter 2). 0 <strong>LEGIONELLA</strong> AND THE PREVENTION OF LEGIONELLOSIS
The risk of legionellosis is increased for those on board ships where legionellae are present in the water systems. Cruise vessels, in particular, have many similarities to hotels in the complexities and operations of their water systems. The risks in ships may also be exacerbated in a number of ways, outlined in Box 7.2. Box . Factors exacerbat ng r sks on board sh ps • When at sea, a ship is a closed environment, and might provide additional opportunities for the transmission of airborne infection. • Water storage and distribution systems on ships are complex, and may provide greater opportunities for bacterial contamination as ship movement increases the risk of surge and back-siphonage. • The risk of sediments in tanks being resuspended and dispersed may be increased by the ship’s movement and by adjustments to the water levels in tanks to maintain the trim of the vessel. • Loaded water may vary in quality and temperature. • In some tropical regions, the risk of bacterial growth in the cold-water system is increased because of higher ambient temperatures. • Ships’ engine rooms are hot, and may affect water temperatures in pipes passing nearby. • The movement of the ship could increase the potential for the formation of aerosols (e.g. in air-conditioning ductwork) where there would not be an equivalent risk ashore. • Proliferation could also result from long-term storage and stagnation of water in tanks or pipes, and this risk could be increased when vessels are laid up for several months. • Legionella can proliferate at temperatures sometimes experienced in stagnant warm water in ships’ plumbing systems, especially in tropical regions, and in storage tanks on ships. • Water can remain in a tank on a ship for a long time in comparison to on land, where storage is usually for less than 24 hours. Source: Edelstein & Cetron (1999) Regional aspects — risk factors Travel-associated infections tend to be diagnosed in the country of residence, because symptoms are often recognized after the patient returns home. The incidence of legionellosis in tourists varies with the country of residence or the outbound country, and the country of infection. The differences may be attributable to differences in diagnostic rates or reporting, rather than to a difference in susceptibility. Historically, the United Kingdom has reported more cases to EWGLINET than other countries, but France, Italy, Germany and the Netherlands have increased their reporting in recent years (EWGLI, 1999, 2001, 2004ab). This increase is probably due to a combination of improved ascertainment (i.e. the determination through diagnostic methodology of whether or not a person is infected with the disease) and improved surveillance. Cases from hotels have also been reported from Japan (Suzuki et al., 2002); Sri Lanka (Wahala & Wickramasinghe, 2000); Beijing, China (Deng, 1993; Peng et al., 2000); Australia (Bell et al., 1996); Serbia and Montenegro (Klismanicacute et al., 1990) and the Caribbean (Schlech et al., 1985). <strong>LEGIONELLA</strong> AND THE PREVENTION OF LEGIONELLOSIS
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LEGIONELLA AND THE PREVENTION OF LE
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LEGIONELLA AND THE PREVENTION OF LE
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Foreword Legionellosis is a collect
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Contents Foreword . . . . . . . . .
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Chapter 5 Cooling towers and evapor
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Chapter 9 Disease surveillance and
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Tables Table 1.1 Main characteristi
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Figure 8.1 Visible biofilm on inter
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Acknowledgements The World Health O
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• John Newbold, Health and Safety
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Executive summary Legionellosis is
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• Health-care facilities — Chap
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Chapter 1 Legionellosis Britt Horne
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Legionnaires’ disease is often in
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1.1.2 Pontiac fever Symptoms Pontia
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Table . Extrapulmonary nfect ons ca
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Proteins produced by the body’s i
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Aspiration may occur in patients wi
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Table . R sk factors for Legionella
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In the outbreak of Legionnaires’
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Table . Potent al treatments for d
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1.4.2 Species and serogroups associ
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Other causes of infection In Europe
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The interaction of virulent legione
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1.5.2 Surface structures involved i
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1.5.4 Host defence The host defence
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Chapter 2 Ecology and environmental
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L. pneumophila is thermotolerant an
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2.2.3 Environmental factors and vir
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Figure 2.1 Biofilm formation Biofil
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2.4 Sources of Legionella infection
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Chapter 3 Approaches to risk manage
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Table . Cool ng tower outbreaks Fac
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Even when a source reaches a state
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The WSP should be prepared in conju
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Identify control measures Control m
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F gure . Dec mal reduct on t mes fo
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Method Advantages D sadvantages Dos
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Validate effectiveness of water saf
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• clear statements of responsibil
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Chapter 4 Potable water and in-buil
Page 83 and 84: The remainder of this chapter provi
Page 85 and 86: 4.3.1 Document and describe the sys
Page 87 and 88: Construction materials — risk fac
Page 89 and 90: Where temperature controls (discuss
Page 91 and 92: 4.4.2 Monitor control measures This
Page 93 and 94: Chapter 5 Cooling towers and evapor
Page 95 and 96: 5.1.1 Cross-flow cooling towers As
Page 97 and 98: water treatments (including chemica
Page 99 and 100: 5.3 System assessment This section
Page 101 and 102: Spray drift — risk factors Even w
Page 103 and 104: The section on control measures for
Page 105 and 106: • periodic or continuous bleed-of
Page 107 and 108: Box . Po nts to be noted when clean
Page 109 and 110: In certain circumstances, samples m
Page 111 and 112: Table . Example documentat on for m
Page 113 and 114: Chapter 6 Health-care facilities Ma
Page 115 and 116: For 1999 and 2000, a total of 384 c
Page 117 and 118: 6.3 System assessment This section
Page 119 and 120: Table . Type of colon zat on of wat
Page 121 and 122: 6.4.1 Identify control measures Thi
Page 123 and 124: 6.5.1 Prepare management procedures
Page 125 and 126: Until the situation is under contro
Page 127 and 128: Chapter 7 Hotels and ships Roisin R
Page 129 and 130: F gure . Detected and reported case
Page 131 and 132: Table . Rev ew of outbreaks (more t
Page 133: 7.2 Water safety plan overview WSPs
Page 137 and 138: Kingdom to 66% in Spain (Starlinger
Page 139 and 140: Agency, Legionella Section, United
Page 141 and 142: Given the complexity of distributio
Page 143 and 144: Chapter 8 Natural spas, hot tubs an
Page 145 and 146: Spas “Natural spa”, denotes fac
Page 147 and 148: Rare cases of Legionnaires’ disea
Page 149 and 150: Process step P pework Water n hot t
Page 151 and 152: Hosepipes may sometimes be used to
Page 153 and 154: Hot tubs that are not effectively d
Page 155 and 156: Nutrients — control measures Bath
Page 157 and 158: Various additives may also be used
Page 159 and 160: • descriptions of any significant
Page 161 and 162: Table . Examples of m crob olog cal
Page 163 and 164: Chapter 9 Disease surveillance and
Page 165 and 166: Exposure histories allow cases to b
Page 167 and 168: F gure . Invest gat ng a s ngle cas
Page 169 and 170: Box . (cont nued) Since the incepti
Page 171 and 172: Country United Kingdom All reported
Page 173 and 174: F gure . Annual reported cases, - 0
Page 175 and 176: Training opportunities Trainees in
Page 177 and 178: Box . Example of terms of reference
Page 179 and 180: ecause doing anything more could un
Page 181 and 182: 9.4 Case studies This section descr
Page 183 and 184: 9.4.4 Concrete batcher process on a
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Chapter 10 Regulatory aspects David
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• validation of the effectiveness
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• operating conditions, such as t
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10.4.6 Outbreak investigation and n
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hot water (e.g. health-care facilit
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General prevent on Country DW Wp SB
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Country General prevent on DW Wp SB
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Chapter 11 Laboratory aspects of Le
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• detection of the bacterium in t
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Method Sens t v ty (%) PCR • Rapi
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11.2.2 Detecting Legionella antigen
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DFA has been used successfully with
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• Serologic testing can be used f
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Although not all strains can be rel
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Generally, any water source that ma
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During outbreak investigations, swa
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• other Legionella species that d
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Appendix 1 Example of a water syste
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Weekly water system check list Week
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Appendix 2 Example of a 2-week foll
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Travel Work/travel in the UK: ❑ Y
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Checklist of local places Health/sp
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Appendix 3 Example of a national su
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Strictly Confidential 2 Hospital Ac
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Glossary aerobic bacteria Bacteria
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health-care acquired Legionellosis
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surveillance The process of systema
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References Abu KY, Eisenstein BI, E
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Barbaree JM et al. (1987). Protocol
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Blatt SP et al. (1994). Legionnaire
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Byrne B, Swanson MS (1998). Express
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Crespi S (1993). Legionella y legio
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Edelstein PH (1982b). Comparative s
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Falguera M et al. (2001). Nonsevere
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Gaia V et al. (2003). Sequence-base
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Hayden RT et al. (2001). Direct det
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Ingram JG, Plouffe JF (1994). Dange
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Ko KS et al. (2003). Molecular evol
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Loret JF et al. (2003). Comparison
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McEvoy M et al. (2000). A cluster o
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Olaechea PM et al. (1996). A predic
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Regan CM et al. (2003). Outbreak of
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Schulze-Robbecke R, Rodder M, Exner
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Surman SB, Morton LHG, Keevil CW (1
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Tully M, Williams A, Fitzgeorge RB
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Welti M et al. (2003). Development
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