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An Outbreak of Acanthamoeba
Keratitis Among Contact Lens
Users – Florida, 2005-2007Statewide Epidemiology Seminar
May 2008
Kateesha McConnell, MPH
Florida Epidemic Intelligence Service Fellow
Roberta M. Hammond, PhD, RS – Bureauof Community Environmental Health, Food and
Waterborne Disease Program
Roger Sanderson, RN, MA
Regional Epidemiologist 2
Acanthamoeba keratitis (AK)
Rare and serious eye infection
Incidence of the disease in the US is estimated at 1-2cases per million contact lens (CL) users
Healthy individuals can get infection but AK primarily inCL users
Unhygienic CL practices, hx of trauma, environmentalfactors
Can cause severe vision outcomes
3
Acanthamoeba
Microscopic amoeba
Common to the Environment
Water
Soil
Air
Drinking water
Sewage systemsSource: Clinical Microbiology Reviews 2003;(16)2; 273-307.
4
Acanthamoeba
Cause of several infections in humans
Acanthamoeba keratitis (AK)
Granulomatous Amebic Encephalitis (GAE)
Disseminated infection
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Risk Factors for AK
Improper storage and handling of lenses
Improper disinfection of lenses (ie. Use of tap water orhomemade solutions to clean the lenses)
Swimming, using a hot tub, or showering while wearinglenses
Coming into contact with contaminated water
Having a history of trauma to the cornea
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Symptoms / Diagnosis
Diagnosis of AK is difficult
Often misdiagnosed
Diagnosis complicated byfrequent occurrence ofsecondary bacterialinfections
Treatment can complicate
diagnosis
Early detection is key
Symptoms
Eye pain
Redness
Blurred vision
Sensitivity to light
Sensation of something ineye
Excessive tearing
(Photo courtesy of Dan B. Jones, M.D.)
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CDC Investigation
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Background
Source: CDC, 2007 “Multi-state Outbreak ofAcanthamoeba Keratitis associated with a ContactLens Solution” – IDSA poster
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Methodology
Source: CDC, 2007 “Multi-stateOutbreak of Acanthamoeba Keratitisassociated with a Contact LensSolution”– IDSA poster 10
CDC Findings
Source: CDC, 2007 “Multi-state Outbreak ofAcanthamoeba Keratitis associated with a Contact
Lens Solution” – IDSA poster
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CDC Findings
Source: CDC, 2007 “Multi-stateOutbreak of Acanthamoeba Keratitisassociated with a Contact LensSolution”– IDSA poster
Survey of Ophthalmology Centersfor AK Cases 1999-2006
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CDC Findings
Source: CDC, 2007 “Multi-stateOutbreak of AcanthamoebaKeratitis associated with a ContactLens Solution” – IDSA poster
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CDC Findings
Source: CDC, 2007 “Multi-state Outbreak ofAcanthamoeba Keratitis associated with aContact Lens Solution”– IDSA poster
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CDC Findings
Source: CDC, 2007 “Multi-state Outbreak ofAcanthamoeba Keratitis associated with aContact Lens Solution”– IDSA poster
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CDC Findings
Source: CDC, 2007 “Multi-stateOutbreak of Acanthamoeba Keratitisassociated with a Contact LensSolution”– IDSA poster
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Conclusions
Source: CDC, 2007 “Multi-state Outbreak
of Acanthamoeba Keratitis associated witha Contact Lens Solution”– IDSA poster
Florida AK Cases
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Case Identification
Websites/Listservs/Emails:
Public health related
Ophthalmology/optometry
Infection control and clinical microbiology
EpiCom and Merlin
Major ophthalmology centers in Florida
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Florida AK Cases
30 cases initially reported
28 from Bascom Palmer Eye Institute(Miami)
2 from out of state sources
26/30 (86.7%) met case criteria for study
symptom onset on or after 1/1/05
culture confirmed
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Florida AK Cases
Of the 26 confirmed cases meeting the
case definition 21 (80.8%) residents
5 (19.2%) non-residents
Most of the 21 cases found in residentswere from south Florida
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Case Demographics
8 total cases 50% -Male
50% - Female
Race/Ethnicity 1 Black – Non-Hispanic
2 White – Non-Hispanic
3 White – Hispanic
2 Other/Unknown – Hispanic
Age Range 16-61 yrs Median age = 30.5 yrs
Mean age = 33.3 yrs
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Case Identification & Interviews
Case Identification
Each case given a unique IDnumber
State ID number
County of residence
Month/year received bystate
Numerical order of receipt• Ex. 01-0507-02
(Alachua County, May2007, Case#2)
FL cases were also assignedan additional ID number by theCDC
Interviews
Case patient interviewsconducted via telephone
8 out of 21 cases (38.1%)participated in this phase
2 refusals byparents/guardians
2 unable to be located
9 did not respond to
repeated requests toparticipate
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Case Identification, Interviews, &
Specimen Collection
Additional case information also obtained from:
Primary Eye Care Provider Interviews
Treating Ophthalmologist Interviews
Review of Medical Records
Specimens retrieved from patients that completed an interview
Specimens shipped to CDC laboratory for analysis
Five specimens from 3 different patients were shipped to CDC foranalysis
3 CL cases
1 box of CLs
1 bottle of CL solution (AMO Complete Moisture Plus)
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Further Investigation
Control interviews conducted for 3 out of 8 cases in thestudy
Random digit dialed phone list from streets surrounding
reference (case) patient
Specified numbers on each list called until matchedcontrols were found Original goal: 2 controls/case
Modified goal:1 control/case
3 controls recruited out of 329 call attempts
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Summary of Florida AK Cases
History of eye injury
3/8 (37.5%)
Swim w/CLs
3/8 (37.5%)
CL use < 5yrs
3/8 (37.5%)
Topping of Solution
5/8 (62.5%)
Sometimes/never washhands before inserting CLs
1/8 (12.5%)
Used AMO Complete
Moisture Plus
4/8 (50.0%)
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Summary of Florida AK Cases
Results of Laboratory specimens
3 CL cases - culture and PCR (-)
1 box of CLs - culture and PCR (-)
1 bottle AMO Complete solution - culture (-) andweakly PCR (+) for Acanthamoeba
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Summary of Florida AK Cases
Clinical outcomes
2 - Corneal transplant
2 - Receiving medical Tx
2 - Resolved
2 - Unknown status
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Next Steps
The CDC is currently in the process ofconducting advanced analysis of the datareceived in 2007
Completed findings will be published in thenear future
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Acknowledgments
Dr. Roberta Hammond
Roger Sanderson
Dr. Thomas ColemanAndre Ourso
Dr. Jennifer Verani
AK Team
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References Cabral FM and Cabral G. Acanthamoeba spp. as agents of disease in humans.
2003;16(2)273-307. Clinical Microbiology Reviews.
Centers for Disease Control and Prevention. Acanthamoeba keratitis associated withcontact lenses-United States. MMWR Morb Mortality Wkly Rep. 1986;35(25);405-8.
Centers for Disease Control and Prevention. Acanthamoeba keratitis in soft-contact lenswearers. MMWR Morb Mortality Wkly Rep. 1987;36(25);397-8,403-4.
Centers for Disease Control and Prevention. Update: Fusarium keratitis –United States,2005-2006. MMWR Morb Mortality Wkly Rep. 2006;55(20);563-4.
Centers for Disease Control and Prevention. Acanthamoeba keratitis multiple states,2005-2007. MMWR Morb Mortality Wkly Rep. 2007;56(21);532-4.
Acanthamoeba infection homewww.cdc.gov/ncidod/dpd/parasites/acanthamoeba/index.htm - Accessed 01/23/08
Acanthamoeba keratitis fact sheetwww.cdc.gov/ncidod/dpd/parasites/acanthamoeba/factsht_acanthamoebakeratitis.htm - Accessed 01/23/08