Preventing Legionella Transmission An Environmental Health View

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1 Preventing Legionella Transmission An Environmental Health View April 25, 2013 Erin Reinsborough Environmental Health Specialist

2 Mission Statement Together with the Halton community, the Health Department works to achieve the best possible health for all. 2

3 Outline Overview of Legionella bacteria and Legionellosis History, Transmission and Sources of Legionella Legionellosis trends in Ontario and Halton Region Susceptible populations Laboratory testing Risk factors for growth of or exposure to Legionella Minimizing risk of Legionella Industry Best Practice Documents City of Toronto Outbreak Legislation What are we doing at Halton Region Heath Department? 3

4 What is Legionella? bacteria naturally occurring in the environment grows in biofilms or slime on the surface of lakes, rivers and streams 52 species, 70 serogroups identified found worldwide 4

5 Legionella - Challenges can grow to high concentrations under the right conditions relatively resistant to chlorine can cause serious disease with high fatality rate affects most vulnerable residents difficult to determine source of exposure disease caused by Legionella appears to be on the rise in Ontario 5

6 Legionellosis caused by Legionella pneumophila and related bacteria severity varies from mild febrile illness (Pontiac fever) to a potentially fatal form of pneumonia (Legionnaires Disease) can affect anyone principally affects those susceptible due to age, illness, immunosuppression and other risk factors, such as smoking not everyone exposed to the organism develops symptoms of disease both Pontiac Fever and Legionnaires Disease are reportable Source: Legionella and the prevention of legionellosis, WHO

7 Pontiac Fever milder form of disease influenza-like illness without pneumonia symptoms include fever, lack of appetite, headache and aching muscles incubation period: 1-2 days recovery usually 2-5 days high attack rate (up to 95%) no deaths reported (PHO/WHO) 7

8 Legionnaires Disease More severe form of illness that causes pneumonia Symptoms: high fever chills cough fatigue headache aching muscles chest pain loss of appetite 8

9 Legionnaires Disease incubation period of 2-10 days, up to 20 days low attack rate (up to 5%) high case fatality rate (5-40%) complications include kidney/respiratory failure and septic shock many cases are treated successfully with antibiotics 9

10 Legionnaires Disease L. pneumophila sg. 1 accounts for over 60% of legionellosis cases in Ontario frequent (unrecognized) cause of communityacquired pneumonia second most common cause of pneumoniarelated admission to ICU Source: Epidemiology of legionellosis, June 5, 2012 Presentation Slides - Public Health Ontario 10

11 History of Legionnaire s Disease L. pnemophila bacteria first identified in American Legion Convention in Philadelphia, USA 240 people ill and 34 deaths retrospectively identified as the cause of outbreaks of Legionnaires disease since 1947 Source: Legionella and the prevention of legionellosis, WHO

12 Mode of transmission inhalation or aspiration of high numbers of Legionella bacteria no established dose response relationship directly from contaminated water (e.g. wound infections no est. link to pulmonary disease) not transmitted from person-to-person Source: Legionella and the prevention of legionellosis, WHO

13 Sources of Legionella Bacteria Linked to Exposures Natural and artificial sources: domestic hot and cold water systems, incl. showers, faucets and toilets wet cooling systems: cooling towers (CT s) and evaporative condensers (EC s) whirlpool spas (spa pools, hot tubs) natural spas humidifiers respiratory therapy equipment/nebulizers 13

14 Sources of Legionella Bacteria Linked to Exposures cont fountains/sprinkler systems grocery store misters compost and potting soil 14

15 Cooling Towers and Evaporative Condensers 15

16 Cooling Towers and Evaporative Condensers implicated in many outbreaks provide cooling for industrial processes and cool water for air-conditioning to buildings heat-transfer devices - warm water cooled by evaporation in atmospheric air air movement through the tower or condenser produced by fans or by natural convection aerosols generated during operation infections linked to sources up to 3.2 km away Source: Legionella and the prevention of legionellosis, WHO

17 Exposure Categories Community-acquired Domestically-acquired Nosocomial Travel-associated (hotels, cruise ships) Source: Legionella and the prevention of legionellosis, WHO

18 Exposure Categories nosocomial cases usually make up a small proportion of reported cases of legionellosis. proportion of fatal cases tends to be much higher with nosocomial infections than with community-acquired infections Source: Legionella and the prevention of legionellosis, WHO

19 Historical Trends Incidence of legionellosis: Ontario, *; Canada and Europe, Note: 2012 counts only include cases reported up to September 5, Source: Epidemiology of legionellosis, June 5, 2012 Presentation Slides - Public Health Ontario 19

20 Possible reasons for recent increased incidence in Ontario changes in local environmental conditions (differences in rainfall and humidity) increased air conditioner use increase in testing: improved recognition and diagnosis by clinicians urine antigen detection method (ease of use) Source: Epidemiology of legionellosis, June 5, 2012 Presentation Slides - Public Health Ontario 20

21 Confirmed cases of legionellosis by month and year: Ontario, * Note: 2012 counts only include cases reported up to September 5, Source: Epidemiology of legionellosis, June 5, 2012 Presentation Slides - Public Health Ontario 21

22 Legionellosis in Ontario, confirmed cases reported in iphis 71% cases identified as Legionnaires disease based on the diagnosis of pneumonia 65% of cases reported in Toronto, Peel, Hamilton and Durham health units Male to female ratio is 2.7:1 Average age is 62 years Source: Epidemiology of legionellosis, June 5, 2012 Presentation Slides - Public Health Ontario 22

23 Risk factors reported in the literature age greater than 50 male more likely than females heavy alcohol consumption those who smoke those having underlying chronic conditions such as: - cancer - chronic obstructive pulmonary disease - end-stage renal disease - diabetes receipt of immunosuppressant therapy (e.g. corticosteroid therapy) Source: Epidemiology of legionellosis, June 5, 2012 Presentation Slides - Public Health Ontario 23

24 Exposure sources among reported cases (iphis, 2011) Cases reported a variety of potential exposures including: Institutions (e.g. long-term care homes) Private homes: taps, showers and air conditioners Misting equipment in grocery stores or on farms Environmental water (e.g. streams, creeks, and lakes) Construction sites Travel outside of Canada Source: Epidemiology of legionellosis, June 5, 2012 Presentation Slides - Public Health Ontario 24

25 Severe outcomes: Ontario, 2011 Hospitalization was reported for 79% of legionellosis cases 9% of cases died Source: Epidemiology of legionellosis, June 5, 2012 Presentation Slides - Public Health Ontario 25

26 Halton Region Statistics, Legionellosis cases reported in iphis: 2011: 7 cases, 0 deaths 2012: 12 cases, 2 deaths 26

27 Testing methods and case identification Urine antigen detection is the most commonly used testing method Advantage: samples easily obtained from patients Limitations: detects L. pneumophila sg.1 but not other Legionella serotypes cannot be cultured cannot link human cases to environmental sources for cluster detection or source identification Source: Epidemiology of legionellosis, June 5, 2012 Presentation Slides - Public Health Ontario 27

28 Testing methods and case identification Diagnosis using lower tract respiratory specimens is recommended Better detection of disease caused by other Legionella serogroups Improved source identification (link human and environmental samples) Source: Epidemiology of legionellosis, June 5, 2012 Presentation Slides - Public Health Ontario 28

29 Legionellosis Chain of Infection amplification of bacteria aerosolization of contaminated source water inhalation/aspiration of contaminated water susceptible host increased risk of infection 29

30 Risk factors for growth of or exposure to Legionella in piped water systems poor water quality and treatment failures distribution system problems such as stagnation and low flow rate construction materials that contribute to microbial growth and biofilm formation Source: Epidemiology of legionellosis, June 5, 2012 Presentation Slides - Public Health Ontario 30

31 Risk factors for growth of or exposure to Legionella in piped water systems cont inefficient or ineffective disinfection water temperature of C presence of biofilms aerosol production Source: Epidemiology of legionellosis, June 5, 2012 Presentation Slides - Public Health Ontario 31

32 Risk factors for growth of or exposure to Legionella in CT s and EC s neglect or insufficient maintenance start-up of stagnant systems without adequate chemical treatment Source: Legionella and the prevention of legionellosis, WHO

33 Minimizing Risk of Legionellosis Cannot eliminate source but can reduce risk 33

34 Factors that promote growth of Legionella bacteria = factors that promote growth of biofilm scale and corrosion warm water temperature* survive and multiply between C optimal: C do not multiply below 20 C can withstand temperatures of up to 50 C for several hours, destroyed almost instantly at 70 C presence of nutrients, both in the source water and in the materials of the system stagnation or low flow * Source: PHO Legionella Workshop Questions and Answers, Public Health Ontario Jan 25,

35 Preventing growth of Biofilm in water systems Use best practices to maintain and operate system: minimize nutrients and microorganisms use chemical treatment to prevent scaling and corrosion prevent low flow and stagnation system design (limit complexity & deadlegs/deadends) frequent flushing of unused water lines temperature control (avoid temperature of C) where possible appropriate use of disinfection (biocides) Source: Legionella and the prevention of legionellosis, WHO

36 Minimizing Risk of Legionellosis follow manufacturer maintenance instructions for operation of CT s, EC s, water systems and hydro-massage tubs maintain mist-producing devices incl. shower heads, faucets, hot tubs and humidifiers Source: Legionella and the prevention of legionellosis, WHO

37 Minimizing Risk of Legionellosis use caution when shutting down to ensure safeguards in place ensure proper cleaning of equipment prior to restart respond to adverse situations: changes in functioning of apparatus external influences; nearby construction and high dust occurrences with CT s good infection control policies and guidelines Source: Recommendations made by Arlene King, Chief Medical Officer of Health 37

38 Best Practice Documents ASHRAE Guideline : Minimizing the Risk of Legionellosis Associated with Building Water Systems Cooling Tower Institute (CTI) Legionellosis Guideline: Best Practices for Control of Legionella 38

39 Legionnaires Disease Outbreak: Long-Term Care Home, City of Toronto fall of 2005 respiratory illness outbreak 135 people infected: 70 residents, 39 staff, 21 visitors, and 5 people who lived or worked nearby 23 residents died Source of outbreak unknown for the first 10 days Source: Report of the Expert Panel on the Legionnaires Disease Outbreak in the City of Toronto September/October 2005, Dr. B. Henry et al., Dec

40 Source: Report of the Expert Panel on the Legionnaires Disease Outbreak in the City of Toronto September/October 2005, Dr. B. Henry et al., Dec

41 Environmental Sampling 1) Water sampling (potable & non-potable) 2) Swab sampling (e.g. shower heads) 3) Solid material sampling (e.g. filters) Source: Public Health Inspector s Guide To the Principles and Practices of Environmental Microbiology, Public Health Ontario, Feb

42 Source of Outbreak cooling towers belonging to the building identified as source but cooling towers said to be well operated and maintained by city staff Source: Report of the Expert Panel on the Legionnaires Disease Outbreak in the City of Toronto September/October 2005, Dr. B. Henry et al., Dec

43 What led to Outbreak? Combination of unusual factors: record breaking summer heat heavier use of cooling system construction at hospital site nearby design of HVAC system Source: Report of the Expert Panel on the Legionnaires Disease Outbreak in the City of Toronto September/October 2005, Dr. B. Henry et al., Dec

44 Legislation Health Protection and Promotion Act Long-Term Care Homes Act Retirement Homes Act Occupational Health and Safety Act Safe Drinking Water Act Building Code Act 44

45 Source: Report of the Expert Panel on the Legionnaires Disease Outbreak in the City of Toronto September/October 2005, Dr. B. Henry et al., Dec

46 What are we doing at Halton Region Health Department? routine investigations for reported cases of Legionellosis educating stakeholders promoting best practices creating an inventory of cooling towers and evaporative condensing units in Halton Region 46

47 In Summary Legionella bacteria is found in the natural environment and in many types of water systems Legionella bacteria can cause severe disease, especially in susceptible populations Transmission occurs when high numbers of the bacteria are aerosolized and then inhaled or aspirated by the host Legionellosis appears to be on the rise in Ontario and Halton Region Operating and maintaining building water systems using industry best practice standards will help to prevent Legionellosis 47

48 Thank you! Questions? 48

49 Resources 1) ASHRAE Guideline : Minimizing the Risk of Legionellosis Associated with Building Water Systems, ) ASHRAE Position Document on Legionellosis, Jan ) Cooling Tower Institute (CTI) Legionellosis Guideline: Best Practices for Control of Legionella 4) Epidemiology of legionellosis, June 5, 2012 Presentation Slides - Public Health Ontario 5) Legionella and the prevention of legionellosis, WHO ) PHO Legionella Workshop Questions and Answers, Public Health Ontario Jan 25, ) Public Health Inspector s Guide To the Principles and Practices of Environmental Microbiology, Public Health Ontario, Feb ) Report Card: Progress in Protecting the Public s Health. Report of the Expert Panel on the Legionnaires Disease Outbreak in the City of Toronto September/October 2005, Dr. B. Henry et al., Dec pdf 49

Legionnaires Disease Q&A (General) (Source: OSHA) (4/29/10)

Legionnaires Disease Q&A (General) (Source: OSHA) (4/29/10) Q. What is Legionnaires Disease? A. Legionnaires disease is a common name for one of the several illnesses caused by Legionella bacteria. Legionnaires