Background of Disease - PowerPoint Presentation

Slide1

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 PhiladelphiaOn January 18, 1977 the causative agent was identified as a previously unknown bacterium, subsequently named LegionellaCausative agent: Ubiquitous gram-negative bacillus that is largely aquatic but can thrive in areas other than lakes and streamsReference: Heymnann, D. L. (2008) Control of Communicable Diseases Manual (19th ed.).  Washington, DC: American Public Health Association. Slide2

Clinical Description

1bLegionalla can cause two distinct clinical diseases:Legionnaires’ diseaseFebrile illness primarily associated with pneumonia Incubation 2-10 days (most commonly 5–6 days) Treatment usually necessary, can be severePontiac feverLess severe form of disease, flu-like symptomsIncubation 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 AssociationSlide3

Two distinct clinical diseases 1b

Legionnaires’ diseaseFebrile illness primarily associated with pneumonia Incubation 2-10 days (most commonly 5–6 days) Treatment usually necessary, can be severe Pontiac feverLess severe form of disease, flu-like symptomsIncubation 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 AssociationSlide4

Susceptibility 1c

Risk Factor for Illness include:Increasing age (most cases are over 50)MalesSmokers (increases risk 2-7 fold)Diabetes mellitusChronic lung or renal diseaseCancer (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 AssociationSlide5

Reservoir and Transmission 1d

Warm water (77-107F) supports the highest concentration of organismsNaturally OccurringLakesStreamsMan-madeWhirlpools 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 AssociationSlide6

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, UtahInfection occurred June 2009-December 2009First notification of cases came in November 2009No cases were found from other facilities using the Fillmore water systemSlide7

Local Environmental Health

2bEnvironmental 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 Slide8

Legal and Regulatory Concerns

2cThe 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 adjustorLegal powers were required to obtain the guest listSlide9

Results and Remediation 2d

Preliminary test result were positive and hotel was temporarily closed Remediation began immediately including:Flushing water systemSuperheating (over 138o 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 Slide10

Case Summary 3a

=Hotel Stay

Case

Age

Sex

Residence

Pool or Spa Use

Showered

Ate in Hotel Restaurant

Case 1

41

M

Washington

Y

Y

Y

Case 2

72

F

United Kingdom

Y

Y

Y

Case 3

70

F

Idaho

Y

Y

Y

Case 4

77

M

Arizona

Y

Y

N

Case 5

61

M

Montana

Y

Y

YSlide11

Final Laboratory Results 3b

PositiveNegativeTotalSwab12 (46%)14 (54%)261L Bottles21 (70%)9 (30%)30Total

33

(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.Slide12

Case Finding

3cOnce the guest list from the previous two weeks was secured, letters were sent alerting patrons of exposureCalls were fielded to answer questions and cross-jurisdictional collaboration ensuedNo other cases were found on the Fillmore water systemSlide13

Wrap-up & Post Remediation 3d

Post-remediation testing results were negativeFollow-up testing continued monthly thereafter for 6 months (through May 2010)The hotel assumed all costs for follow-up testingSince 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