Blacks account for nearly half of the more than 1 million Americans with HIV, according to federal data released on Monday that suggests the battlelines of the nation’s AIDS epidemic are marked as much by race as by sexual orientation.

An estimated 1,039,000 to 1,185,000 Americans were living with HIV at the end of 2003, the Centers for Disease Control and Prevention said at the 2005 National HIV Prevention Conference in Atlanta.

Forty-seven percent were black, a disproportionate figure considering that blacks make up about 13 percent of the U.S. population. Whites accounted for 34 percent of the HIV-positive population and Hispanics 17 percent.

Gay and bisexual men made up 45 percent of the total.

“The HIV epidemic, initially most prominent among white gay men, has expanded to affect a wide range of populations, with African-Americans now most severely impacted,” Dr. Ron Valdiserri, deputy director of the CDC’s HIV, STD and TB prevention programs, told reporters in a conference call.

In a separate analysis of 1,767 men who have sex with men, CDC researchers found that 46 percent of blacks were infected. That compared to 21 percent of whites in the group and 17 percent of the Hispanics, according to the study, which was carried out in five U.S. cities and presented at the conference.

MOST UNAWARE

The researchers also discovered that 67 percent of the black men in the group did not know they were infected before participating in the study, more than three times the percentage of whites who were unaware.

Valdiserri said providing gay and bisexual black men and other high-risk subgroups with testing and prevention services was a key step to halting the spread of HIV.

AIDS, which destroys the immune system and leaves victims vulnerable to opportunistic infections and cancers, has killed about a half million Americans and at least 22 million people worldwide since 1981.

Health experts have been warning of a possible resurgence of the epidemic, which eased in the early 1990s following the development of antiretroviral drugs targeting the disease.

Since the late 1990s, when U.S. deaths from AIDS stabilized at 16,000 per year and new HIV infections stabilized at 40,000 per year, the disease has shown signs of a comeback among gay and bisexual men and intravenous drug users.

The CDC, however, said it was possible that the make-up of the HIV positive population would shift in coming years to reflect a higher proportion of infections among blacks, women and individuals infected by high-risk heterosexual contact.

To combat the changing scope of HIV, the U.S. government is emphasizing programs that focus on testing and counseling people who are already infected.

AIDS activists, however, attack the approach, which was introduced two years ago, because they believe it leads to reduced funding for programs that emphasize condom use and other safe-sex practices for uninfected people.

The government recommends that pregnant women, intravenous-drug users and anyone who engages in unsafe sex receive routine HIV testing.