Half of all men carrying the AIDS virus who were tested in a Chicago survey were unaware they were infected, according to a study released Friday by the Chicago Public Health Department.

Although HIV infection rates have been tracked by the city for years, this is the first time the Health Department has conducted HIV tests on men who have sex with men as part of a survey on HIV infection, city officials said.

In the study, conducted in 2008 by two Health Department epidemiologists, 524 men were tested and 91 of them were HIV positive. Half of those who tested positive did not know they were infected.

Overall, the rate of infection among the sampled group was 17.4 percent, an indication that an estimated 1 in 5 gay men in Chicago are HIV-Positive. Among all men in Chicago, the rate is about 1.2 percent, according to the study.

The findings confirm prior information about the AIDS epidemic in Chicago, and are consistent with rates in other large cities. Still, the results emphasize the need for more work to combat HIV transmission in Chicago, said Assistant Health Commissioner Christopher Brown.

"These rates are unacceptably high -- and clearly there is a need for continued, substantial efforts to reach people at risk with effective HIV education and testing services," Brown said.

The HIV infection rates among minorities are higher than whites and higher among older men than younger, according to the survey results.

Among 18- to 24-year-olds, the infection rate was 13.6 percent; for those older than 45, it was 22 percent. Among white men, the infection rate was 11.3 percent; among black men, it was 30.1 percent; and among Hispanic men, it was 12 percent.

"This report presents a sobering look at one very troubling aspect of the HIV epidemic and should serve as a call to action for everyone," added Alicia Ozier, Executive Director of TaskForce Prevention and Community Services. "Everyone engaged in the fight against HIV---from grassroots activists to service providers to grant writers and researchers---should use this document as a tool to better understand and better confront HIV in Chicago."

The document was released at a press conference at the West Side headquarters of TaskForce Prevention and Community Services. It was co-authored by CDPH epidemiologists Nikhil Prachand and Britt Skaathun Livak.

ChicagoBreakingNews.com contributed to this story.

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