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Published Date: 2007-05-27 13:00:01
Subject: PRO/EDR> Acanthamoeba keratitis - USA (Multistate)
Archive Number: 20070527.1703

ACANTHAMOEBA KERATITIS - USA (MULTISTATE)
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A ProMED-mail post
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International Society for Infectious Diseases
<http://www.isid.org>
Date: Sat 26 May 2007
Source: CDC Morbidity & Mortality Weekly report Dispatch [edited]
<http://www.cdc.gov/mmwr/preview/mmwrhtml/mm56d526a1.htm?s_cid=mm56d526a1_e>

In May 2006, the Illinois Department of Public Health (IDPH) informed
CDC about a possible increase in _Acanthamoeba keratitis_ (AK) at an
ophthalmology center in Illinois during the preceding 3 years. The
University of Illinois at Chicago (UIC) was investigating this
possible increase. In October 2006, IDPH updated CDC about the
ongoing UIC investigation. At that time, CDC informally contacted
multiple ophthalmology centers in the United States to assess whether
the potential increase in cases extended beyond Illinois. Responses
from the ophthalmology centers were inconclusive. In January 2007,
CDC initiated a retrospective survey of 22 ophthalmology centers
nationwide to assess whether cases were increasing throughout the
United States. In March 2007, data received from 13 centers
demonstrated an increase in culture-confirmed cases of AK with wide
geographic distribution. The increase in cases had begun in 2004 and
continued to the present. On 16 Mar 2007, CDC initiated a multistate
investigation to look for risk factors associated with this increase
in AK cases. This report summarizes recent preliminary results of
that investigation, which indicated an association with AK in soft
contact lens wearers who used Advanced Medical Optics (Santa Ana,
California) Complete MoisturePlus (AMOCMP) multipurpose cleaning
solution. CDC and the Food and Drug Administration (FDA) are taking
steps to notify the public and the medical and public health
communities of this preliminary association. The manufacturer has
undertaken a voluntary recall of the product.
AK, a rare but potentially blinding infection of the cornea, is
caused by a ubiquitous, free-living ameba (_Acanthamoeba_) that is
found commonly in the environment, including water (e.g., tap and
recreational water), soil, sewage systems, cooling towers, and
heating/ventilation/air conditioning (HVAC) systems. AK primarily
affects otherwise healthy persons who wear contact lenses; an
estimated 85 percent of U.S. cases occur in contact lens wearers
(including wearers who follow recommended contact lens-care
practices) (1). Persons who improperly store, handle, or disinfect
their lenses (e.g., by using tap water or homemade solutions for
cleaning); swim, use hot tubs, or shower while wearing lenses; come
in contact with contaminated water; have minor damage to their
corneas; or have previous corneal trauma are at increased risk for
infection (2). Based on an analysis of cases reported to CDC during
1985-1987, the incidence of AK in the United States has been
estimated at one to 2 cases per million contact lens users (3,4). An
estimated 30 million persons in the United States wear soft contact lenses (5).
Initial case finding for this investigation was facilitated through
postings on the Epidemic Information Exchange (Epi-X), on
ophthalmology/optometry/infection control listservs and websites, and
through queries of clinical microbiology laboratories. As of 24 May
2007, a total of 138 patients with onset of symptoms on or after 1
Jan 2005 and positive _Acanthamoeba_ cultures from corneal specimens
had been reported to CDC by public health authorities and
ophthalmologists from 35 states and Puerto Rico. Standardized
telephone interviews of patients, ophthalmologists, and primary
eye-care providers are being conducted by state and local health
officials and CDC. Laboratory testing of clinical specimens, contact
lenses, bottles of solution, and contact lens cases received from AK
patients, including typing of _Acanthamoeba_ spp. isolates, is
ongoing. An initial analysis was conducted using data from the 1st 46
completed patient interviews.
Among the 46 culture-confirmed patients who were interviewed, the
median age was 40 years (range: 15--77 years); 6 (13 percent) were
aged <18 years. 27 (59 percent) were female. Of the 37 of these
patients for whom clinical data were available, medical therapy was
unsuccessful for 9 (24 percent), and they were required or expected
to undergo corneal transplantation. Of the 46 patients, 39 (85
percent) wore soft contact lenses, 3 (7 percent) wore rigid lenses,
and 4 (9 percent) reported no contact lens use. Among the 42 contact
lens users, 16 (38 percent) reported swimming while wearing contact
lenses and 35 (83 percent) reported showering while wearing contact
lenses during the month before symptom onset.
Among the 39 soft contact lens users, 36 reported using one or more
specific types of contact lens solution, 21 of these (58 percent)
reported any use of AMOCMP in the month before symptom onset, 20 (56
percent) reported using AMOCMP as their primary solution, and 14 (39
percent) reported using AMOCMP as their exclusive solution. Exposure
data from the 36 patients who wore soft contact lenses and used any
type of contact lens solution were compared with exposure data from
controls who were interviewed as part of the 2006 CDC _Fusarium_
keratitis outbreak investigation (6). These controls, who were
selected as geographically matched controls for the _Fusarium_
keratitis cases, represented a sample of adult soft contact lens
wearers from different U.S. states who were asked about product use
and behaviors during March 2006 (6).
The 14 AK soft contact lens-wearing case-patients with symptom onset
dates before 1 Apr 2006 (the period most comparable to _Fusarium_
controls) who reported use of a single solution were compared with
115 controls from the _Fusarium_ investigation who reported using a
single solution. The results indicated that (29 percent) of the 14 AK
case-patients had used AMOCMP, compared with 6 (5 percent) of the 115
_Fusarium_ controls (odds ratio: 7.3 [95 percent confidence interval
(CI) = 1.7--30.1]). In a separate comparison, 36 soft contact
lens-wearing AK case-patients with symptom onset dates before 24 May
2007 who reported use of one or more solutions were compared with 124
_Fusarium_ controls who reported using one or more solutions. The
results indicated that 21 (58 percent) of the 36 AK case-patients had
used AMOCMP, compared with 8 (6 percent) of the 124 _Fusarium_
controls (odds ratio: 20.3; [CI = 7.6--53.9]). AMOCMP lot numbers
were available for 10 patients who reported using the solution; no
single lot number was repeated, suggesting that AMOCMP was not
intrinsically contaminated. Analysis of the reported use of other
brands of contact lens solution did not reveal any statistically
significant associations.
The AK investigation by CDC, state and local health departments, FDA,
and other partners, is continuing, and interviews of the remaining
patients with culture-confirmed AK, their treating ophthalmologists,
and their primary eye- care providers are ongoing. Although the
results of initial analyses are preliminary, they suggest that use of
AMOCMP increases the risk for AK. Additional studies will provide a
more definitive assessment of the risk associated with use of AMOCMP.
However, based on the preliminary findings, persons who wear soft
contact lenses and who use AMOCMP should 1) stop using the product
immediately and discard all remaining solution, including partially
used or unopened bottles; 2) choose an alternative contact lens
solution; 3) discard current lens storage container; 4) discard their
current pair of soft lenses; 5) see a health-care provider if they
experience any signs of eye infection, including eye pain or redness,
blurred vision, sensitivity to light, sensation of something in the
eye, or excessive tearing.
Contact lens users with questions regarding which solutions are best
for them should consult their eye-care provider. Patients should also
consult their eye-care provider if they have any of the following
symptoms: eye pain or redness, blurred vision, sensitivity to light,
sensation of something in the eye, and/or excessive tearing. AK
symptoms, which can last several weeks to months, vary among
patients. Early in the infection, symptoms can be similar to the
symptoms of other more common eye infections; however, AK can result
in vision loss or blindness if untreated.
All contact lens wearers should follow established guidelines to help
reduce the risk for eye infections, including AK. Primary-care
clinicians evaluating contact lens users with symptoms of eye pain or
redness, tearing, decreased visual acuity, discharge, sensitivity to
light, or foreign body sensation should consider the diagnosis of AK
and refer patients to an ophthalmologist, if appropriate. Diagnosis
of AK requires a high degree of suspicion, especially in a contact
lens wearer with a recent diagnosis of another form of keratitis,
such as herpes simplex virus keratitis, who is not responding to
therapy. Diagnosis of AK is based on clinical presentation and
isolation of organisms from corneal culture or detection of
trophozoites and/or cysts on histopathology. However, a negative
culture does not necessarily rule out _Acanthamoeba_ infection.
Confocal microscopy and polymerase chain reaction assays to detect
_Acanthamoeba_ can also assist with diagnosis. Early diagnosis can
greatly improve treatment efficacy.
Clinicians should consider obtaining clinical specimens (e.g.,
corneal scrapings) for culture before initiating treatment.
Clinicians or microbiology laboratories should report cases of AK to
state and local health departments or directly to CDC at telephone
770-488-7775. _Acanthamoeba_ isolates should be submitted to state
laboratories according to instructions provided by local and state
public health laboratories. Public inquiries should be made via
telephone 800-CDC-INFO. Further information regarding _Acanthamoeba_
infections is available at
<http://www.cdc.gov/ncidod/dpd/parasites/acanthamoeba /index.htm>.
[Reported by: K Bryant, J Bugante Los Angeles County Health Dept; T
Chang, DVM, S Chen, MPH, J Rosenberg, MD, California Dept of Health
Svcs. R Hammond, PhD, K McConnell, MPH, R Sanderson, MA, Florida Dept
of Health. J Elm, MS, M Nakata, C Wakida, Hawaii Dept of Health. C
Austin, DVM, J Bestudik, MG Bordson, C Conover, MD, Illinois Dept of
Public Health. L Granzow, MPH, Indiana Dept of Health. A Pelletier,
MD, V Rea, MPH, Maine Dept of Health and Human Svcs. A Chu, MHS, E
Luckman, MPH, Maryland Dept of Health and Mental Hygiene. K Signs,
DVM, Michigan Dept of Community Health. J Harper, MS, Minnesota Dept
of Health. T Damrow, PhD, E Mosher, Montana Dept of Public Health and
Human Svcs. K Kruger, North Dakota Dept of Health. E Saheli, MPH,
Ohio Dept of Health. M Cassidy, J Hatch, Oregon Public Health Div,
Dept Human Svcs. A Weltman, MD, Pennsylvania Dept of Health. EJ
Garcia Rivera, MD, Y Garcia, MPH, Puerto Rico Dept of Health. MA
Kainer, MD, Tennessee Dept of Health. J Archer, MS, Wisconsin Dept of
Health and Family Svcs. C Joslin, OD, Univ of Illinois Chicago. P
Cernoch, Methodist Hospital of Houston; D Jones MD, M Hamill MD, A
Matoba MD, S Pflugfelder MD, K Wilhelmus, MD, Baylor College of
Medicine, Texas. S Beavers, MD, T Chen, MD, K Christian, DVM, M
Cooper, MD, D Dufficy, DVM, M Gershman, MD, M Glenshaw, PhD, A Hall,
DVM, S Holzbauer, DVM, A Huang, MD, A Langer, DVM, Z Moore, MD, AS
Patel, PhD, LR Carpenter, DVM, J Schaffzin, MD, J Su, MD, I Trevino,
DVM, T Weiser, MD, P Wiersma, MD, S Lorick, DO, JR Verani, MD, EIS
officers, CDC]

Acknowledgments:
The findings in this report are based, in part, on contributions by M
Bonhomme, N Pressly, M Robboy, OD, J Saviola, OD, E Woo, Food and
Drug Admin. MJ Beach, PhD, C Braden, MD, S Brim, MA, D Chang, MD, F
Chow, A daSilva, PhD, AJ Deokar, MPH, R Greco Kone, MPH, S Johnston,
MS, AS Kusano, MS, B Park, Y Qvarnstrom, PhD, MD, S Persaud, S Roy,
MD, G Visvesvara PhD, D Wagner, K Wannemuehler, MS, JS Yoder, MPH,
National Center for Zoonotic, Vector-Borne, and Enteric Diseases, CDC.
References:
1. Stehr-Green JK, Bailey TM, Brandt FH, Carr JH, Bond WW, Visvesvara
GS. Acanthamoeba keratitis in soft contact lens wearers: a
case-control study. JAMA 1987;258:57--60.
2. Parmar DN, Awwad ST, Petroll WM, Bowman RW, McCulley JP, Cavanagh
HD. Tandem scanning confocal corneal microscopy in the diagnosis of
suspected Acanthamoeba keratitis. Ophthalmology 2006;113:538--47.
3. Schaumberg DA, Snow KK, Dana MR. The epidemic of Acanthamoeba
keratitis: where do we stand? Cornea 1998;17:3--10.
4. Stehr-Green JK, Bailey TM, Visvesvara GS. The epidemiology of
Acanthamoeba keratitis in the United States. Am J Ophthalmol 1989;107:331--6.
5. US Environmental Protection Agency. Do you wear contact lenses?
There's something you should know. Available at
<http://www.epa.gov/waterscience/acanthamoeba>.
6. Chang DC, Grant GB, O'Donnell K, et al. Multistate outbreak of
_Fusarium_ keratitis associated with use of a contact lens solution.
JAMA 2006;296:953-- 63.
--
Communicated by: ProMED-mail rapporteur Brent Barrett
[The manufacturer of Advanced Medical Optics (Santa Ana, California)
Complete MoisturePlus (AMOCMP) multipurpose cleaning solution has
undertaken a voluntary recall of the product. With a estimated
incidence of approximately 2 per one million users of the contact
lenses it is very difficult to detect an increased risk. A high level
of suspicion and appropriate sampling as described above is needed to
detect the infections as early as possible. - Mod.EP]

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