Back to Annual Meeting

Back to Annual Meeting

APHA Scientific Session and Event Listing

Charlotte E. Joslin, School of Public Health, University of Illinois at Chicago, 2121 West Taylor Street, Chicago, IL 60612, (312) 996-6625, jrinsky@asph.org

Purpose: Acanthamoeba keratitis (AK) is a severe corneal infection causing scarring. It is extremely rare, with US annualized incidence rates between 1.65-2.01 cases per million contact lens wearers. The purpose is to characterize AK cases and analyze geographical distribution. Methods: All AK cases diagnosed at the UIC Cornea Service between 6/1/03–11/30/05 were included in analysis. Patients with keratitis were defined as cases through confocal microscopy, histology and/or positive cultures. Exploratory analyses were performed to evaluate the AK geographical case distribution. County population data was extracted from Census 2000 data and rates were age-standardized to Cook County. Poisson regression analysis was used to estimate the rate ratio (RR) between AK cases and county of residence. Current cases (6/1/03–11/30/05) were compared to historical cases (6/1/00–11/30/02) to determine if current AK diagnosis rates differed from historical. Results: Forty-two AK cases were diagnosed between 6/1/03–11/30/05. Average age was 28.7 ± 15.2 (SD), 52.4% were male, and 92.9% used contact lenses. Estimated RR measures demonstrated increased rates for all counties relative to Cook, which were significant for DuPage (RR=4.04; 95%CI=1.68-9.22) and Will (4.39; 1.55-10.94). Current AK diagnosis rates were significantly elevated compared to historical rates (7.00; 3.22-18.35). Conclusions: AK case frequency is increasing, and cases are unevenly distributed geographically. We are hypothesizing that recent U.S. EPA changes decreasing allowable amounts of carcinogenic disinfection byproducts in the water supply may have shifted microbial risk balances and increased AK risk. Further research is warranted to better understand the increase and unusual geographical distribution.

Learning Objectives: At the conclusion of the session, the participant will be able to

• describe the recent increase in AK;
• describe the geographical distribution of AK cases; and,
• understand the hypothesis and biological plausibility behind the increase in AK risk.

Keywords: Disease Data, Data/Surveillance

Presenting author's disclosure statement:

Not Answered