The workers offer condoms and free HIV tests to anyone out on the streets they're walking that night. A quick swab of your mouth and you can find out in two weeks if you have the sexually-transmitted, potentially lethal virus that causes AIDS.

Here is what the test-givers hear:

No. I'm not gay.

No. I'm married.

No. You should go to (insert the name of a predominantly black neighborhood.)

More than two decades after human immunodeficiency virus and its severest form, acquired immune deficiency syndrome, became part of the American consciousness, more than a year since St. Lucie County had the highest infection rate in Florida among black women and sixth-highest in the state for white women, people still act as if HIV and AIDS are someone else's problem.

And that — that denial, that ignorance, that refusal to talk about it — keeps HIV infection rates high in St. Lucie County despite the few prevention programs in place.

"People don't perceive themselves as being at risk because they fit into a certain class, or because they're not a sex worker or because they're not on drugs," said Dawn Jones, HIV/AIDS program coordinator for St. Lucie County Health Department. "It's destroying the community."

If you don't think you're at risk, Jones said you don't change behavior. You don't protect yourself with abstinence, a condom or regular testing.

Heterosexual women — of all races — are the most at risk on the Treasure Coast. A rising number of cases involve women infected by a man who, unbeknownst to the woman, has had sexual activity with other men, Jones said. HIV is most easily transmitted from a man.

Jones attributed some of these cases, especially in the black community where infection rates are highest, to time in prison.

"They were surviving in prison," Jones said. "Of course they don't want to admit that happened because they want to reclaim their manhood. So they go back to their girlfriends or their wives."

But ignorance of risk isn't the only factor keeping rates high. Sometimes people don't even know how HIV works.

"You've got people who still think you can get it by sitting on a toilet seat," said Olive Wedderburn, who represents the Treasure Coast on a state HIV prevention panel.

HIV is transmitted through blood, semen and vaginal fluids and primarily transmitted through sex, sharing needles or by being exposed to it before birth or by breastfeeding. Some teenagers in the community hear "sex," think only vaginal sex counts and end up putting themselves at even greater risk by participating in anal or oral sex, said Wedderburn, who also runs Yes Inc., an outreach program for St. Lucie County teens.

Churches and other community leaders preach abstinence and monogamy, if they address sexual health at all. Health officials agree abstinence is the only completely effective prevention method, but say the reality is many young people aren't practicing that.

Nearly half of the 1,876 HIV/AIDS cases in St. Lucie County are people younger than 40 years old.

"Everyone's sleeping with everyone," said Jeron Atwater, one of the street outreach workers from In the Image of Christ. "It just flows. It flows."

Some young girls are looking for older men, Atwater said. These men — who might or might not have HIV, who might not care if they infect someone else — drive flashy cars and throw around cash, giving the girls generous gifts. And once they're done, the girl — who might now have HIV — goes back to dating young boys, boys who see manhood as sleeping with many different women.

Blacks are sleeping with whites who are sleeping with Hispanics, Atwater said. No one is discriminating.

Because HIV-infected people can live for years now on medication, the virus seems like a small risk for some teens.

And then there are the people who just don't want to know.

Whether they have HIV or not, there are people who don't want to talk or think about HIV, AIDS — or even sex, health officials and activists said.

In The Image of Christ does street testing because some people refuse to go to the health department for fear of others assuming they have HIV. Others figure as long as they don't know they have it, HIV isn't going to affect their lives.

"I know it's not an easy subject to talk about," Jones said. "HIV has always been taboo. But the more we talk about it, the more we decrease the stigma."

•HIV is transmitted through blood, semen and vaginal fluids and primarily transmitted through sex, sharing needles or by being exposed to it before birth or by breastfeeding.

•Heterosexual women — of all races — are the most at risk on the Treasure Coast.

•Nearly half of the 1,876 HIV/AIDS cases in St. Lucie County are people younger than 40 years old.