The rate of new infections declined in black women and in many black men -- with the exception of men having sex with other men, Durant's team reported.

"Despite reductions in diagnoses among African American men and women, HIV continues to pose a major health threat," the CDC said in a statement.

"Despite possible signs of success, HIV continues to exact a disproportionate and devastating toll on African Americans."

Durant and colleagues found that the rate of HIV diagnosis fell by 6.8 percent annually among black women and 4.4 percent annually among black men between 2001 and 2004.

The HIV diagnosis rate even fell by 9.7 percent every year on average among black male users of injected drugs, the CDC study found.

Blacks still had a substantially higher infection rate than other ethnic groups, the CDC team told the Conference on Retroviruses and Opportunistic Infections being held in Denver.

"For African-American men, it is seven times the rate of white men and for African-American women it is 21 times the rate of whites," Dr. Kevin Fenton, director of the National Center for HIV, sexually transmitted diseases and tuberculosis, said in an interview.

CDC officials noted the declines were in the number of new diagnoses -- not necessarily new infections.

IMPROVING AWARENESS

Fenton said public health experts need to work harder to make people aware that AIDS is still an epidemic, to inform them about the benefits of getting tested and to let them know there are treatments available that can keep them healthy, even if there is no cure.

"Some of the factors which are preventing them from getting tested are stigma and fear," Fenton said. People fear rejection from family and friends if they test positive for HIV.

"They hear that these treatments are expensive and wonder how they could possibly afford it," he added.

"What we need is a long-term and sustained effort."

Fenton said the entertainment industry, media and other community figures could be put to better use, and better options made available for people to get the often-expensive HIV drugs.

The human immunodeficiency virus that causes AIDS is spread by homosexual and heterosexual sex, by sharing needles with someone who is infected, or via blood transfusions. Infected mothers can pass the virus to their babies.

The virus infects close to 40 million people worldwide and more than 1 million people in the United States.

The CDC estimates that 40,000 Americans become infected with HIV each year.

A second study presented at the same conference found that 32 percent of black men in Baltimore who had sex with other men, which includes homosexual and bisexual activity, were infected with HIV.

More than 9 percent of the 891 men became infected with HIV during the year of the study.