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Background of Disease 1a Legionnaires' disease acquired its name in July 1976 when an outbreak of pneumonia and other respiratory illnesses occurred among.

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Presentation on theme: "Background of Disease 1a Legionnaires' disease acquired its name in July 1976 when an outbreak of pneumonia and other respiratory illnesses occurred among."— Presentation transcript:

1 Background of Disease 1a Legionnaires' disease acquired its name in July 1976 when an outbreak of pneumonia and other respiratory illnesses occurred among people attending a convention of the American Legion in Philadelphia On January 18, 1977 the causative agent was identified as a previously unknown bacterium, subsequently named Legionella Causative agent: Ubiquitous gram-negative bacillus that is largely aquatic but can thrive in areas other than lakes and streams Reference: Heymnann, D. L. (2008) Control of Communicable Diseases Manual (19 th ed.). Washington, DC: American Public Health Association.

2 Clinical Description 1b Legionalla can cause two distinct clinical diseases: Legionnaires’ disease – Febrile illness primarily associated with pneumonia – Incubation 2-10 days (most commonly 5–6 days) – Treatment usually necessary, can be severe Pontiac fever – Less severe form of disease, flu-like symptoms – Incubation 5-72 hrs (most commonly 24–48 hours) – Resolves without treatment in 2-5 days Reference: Heymann, D.L. (2008). Control of Communicable Diseases Manual (19 ed.). Washington, DC: American Public Health Association

3 Two distinct clinical diseases 1b Legionnaires’ disease – Febrile illness primarily associated with pneumonia – Incubation 2-10 days (most commonly 5–6 days) – Treatment usually necessary, can be severe Pontiac fever – Less severe form of disease, flu-like symptoms – Incubation 5-72 hrs (most commonly 24–48 hours) – Resolves without treatment in 2-5 days Reference: Heymann, D.L. (2008). Control of Communicable Diseases Manual (19 ed.). Washington, DC: American Public Health Association

4 Susceptibility 1c Risk Factor for Illness include: Increasing age (most cases are over 50) Males Smokers (increases risk 2-7 fold) Diabetes mellitus Chronic lung or renal disease Cancer (especially lung cancer or leukemia) Immunocompromised (increases risk 2-6 fold) Reference: Heymann, D.L. (2008). Control of Communicable Diseases Manual (19 ed.). Washington, DC: American Public Health Association

5 Reservoir and Transmission 1d Warm water (  F) supports the highest concentration of organisms Naturally Occurring Lakes Streams Man-made Whirlpools Showers Cooling towers Transmission thought to occur via inhalation of aerosolized water or aspiration Reference: Heymann, D.L. (2008). Control of Communicable Diseases Manual (19 ed.). Washington, DC: American Public Health Association

6 Public Health Response 2a Federal, state and local public health collaborative efforts identified and investigated a cluster of Legionella cases whose only commonality was staying at the same hotel in Fillmore, Utah Infection occurred June 2009-December 2009 First notification of cases came in November 2009 No cases were found from other facilities using the Fillmore water system Environmental Assessment Sample Collection & Laboratory Testing Remediation & Case Investigation

7 Local Environmental Health 2b Environmental Health Scientist visited the site and conducted an environmental assessment to determine possible reservoirs for Legionella This also served to guide sampling methods and remediation recommendations

8 Legal and Regulatory Concerns 2c The hotel owner worked well with public health for the assessment and remediation It was difficult to acquire a guest list for notifying patrons of exposure due to the influence of the hotels’ insurance adjustor Legal powers were required to obtain the guest list

9 Results and Remediation 2d Preliminary test result were positive and hotel was temporarily closed Remediation began immediately including: – Flushing water system – Superheating (over 138 o F) – Hyper-chlorination (Note: Some showerheads were ruined by corrosion during remediation) Maximum hot water temperatures at the end of the water system line was found to be low (90 o F) The temperature on the water heater thermostat had been reduced per guest complaint of water being too hot

10 Case Summary 3a =Hotel Stay CaseAgeSexResidencePool or Spa Use ShoweredAte in Hotel Restaurant Case 141MWashingtonYYY Case 272FUnited KingdomYYY Case 370FIdahoYYY Case 477MArizonaYYN Case 561MMontanaYYY

11 Final Laboratory Results 3b PositiveNegativeTotal Swab12 (46%)14 (54%)26 1L Bottles21 (70%)9 (30%)30 Total33 (59%)23 (41%)56 Two types of samples were obtained 1 L bottle samples taken from hot water sources Routine sample for the lab Swab samples from showerheads and faucets This was the first time the lab had processed swab samples Final results were positive for over half (59%) of the samples. Pool and spa samples were negative.

12 Case Finding 3c Once the guest list from the previous two weeks was secured, letters were sent alerting patrons of exposure Calls were fielded to answer questions and cross-jurisdictional collaboration ensued No other cases were found on the Fillmore water system

13 Wrap-up & Post Remediation 3d Post-remediation testing results were negative Follow-up testing continued monthly thereafter for 6 months (through May 2010) The hotel assumed all costs for follow-up testing Since results were negative, subsequent post- remediation testing were only done on six sites –The thermostat settings on the water heaters were increased –The hotel was advised to retrofit mixing valves in guest rooms All follow-up lab results were negative –The hotel was advised to perform periodic testing


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