Epidemiological Characteritic of a Chicago-area Acanthamoeba Keratiti Outbreak Original Reearch Article

Purpoe To characterize Acanthamoeba keratiti (AK) cae and analyze the geographical ditribution within the Chicago-Gary-Kenoha metropolitan area, Chicago, Illinoi, UA. Deign Retropective, population-baed cohort tudy. Method All AK cae diagnoed at the Univerity of Illinoi at Chicago Cornea ervice from June 1, 2003, to November 30, 2005, were included in analyi. Patient with keratiti were defined a cae through confocal microcopy, hitology, and/or poitive culture. Exploratory analye were performed to evaluate whether AK cae were unequally ditributed geographically. County population data were extracted from U Cenu 2000 data, and rate were age-tandardized to Cook County. Poion regreion analyi wa ued to etimate the age-tandardized rate ratio (RR) between AK cae and county of reidence. Current cae (June 1, 2003 to November 30, 2005) were compared with hitorical cae (June 1, 2000 to November 30, 2002) to determine if the current rate of AK diagnoi differed from hitorical rate. Reult Forty AK cae were diagnoed between June 1, 2003 and November 30, 2005. The average (±D) age of patient with AK wa 28.0 ± 15.0 year (range, 13 to 70 year), 52.5% were men, and 95.0% wore contact lene. Etimated RR meaure demontrated increaed rate for all countie relative to Cook, and were ignificant for both DuCounty (RR 3.59; 95% confidence interval [95% CI] 1.44, 8.39) and Will County (RR 3.66; 95% CI 1.18 to 9.56). Current AK diagnoi rate were ignificantly higher than hitorical rate (RR 6.67; 95% CI 3.05 to 17.52). Concluion AK cae are increaing in frequency. The increaed rate are unevenly ditributed in the tudy area. Further reearch i warranted to better undertand the increae and unuual geographical ditribution.