The rate of new HIV infections in the U.S. fell over the last decade, but progress wasn't equal for all groups, according to a new government report.

Across the country, new diagnoses of HIV, the virus that causes AIDS, fell by about 20 percent between 2005 and 2014. But the Centers for Disease Control and Prevention (CDC) says gay and bisexual men and people living in the South didn't see the same benefit.

"There is uneven progress and ongoing severe disparities," said Dr. Jonathan Mermin, who is director of the National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention at the CDC in Atlanta.

For example, he told Reuters Health by phone, in 2014, about 70 percent of new diagnoses of HIV, or human immunodeficiency virus, were among men who have sex with men - including those who inject drugs.

Over the last decade, new HIV infections increased by 24 percent among Latino gay and bisexual men but fell by 18 percent among their white counterparts.

Diagnoses also rose by 22 percent among black gay and bisexual men but leveled off since 2010. Younger black gay and bisexual males, ages 13 to 24, had an 87 percent increase in new HIV infections, but that too leveled off and even declined slightly after 2010.

Southern U.S. states, home to a third of the country's population, accounted for 44 percent of its HIV-infected individuals in 2012. And HIV patients in those states died at three times the rate of people living with HIV in other parts of the country.

"We’ve shown great differences among states, especially in the South, where they are years behind the rest of the U.S. in providing key preventive services," Mermin said. "That manifests itself in different health outcomes."

People in Southern states also tended to be less likely to know their HIV status, according to the report, which was released Sunday at the beginning of the National HIV Prevention Conference in Atlanta.

Jennifer Kates, director of global health and HIV policy at the Kaiser Family Foundation in Washington, D.C., told Reuters Health it's important for people to know if they're infected, because they can protect their own health and that of others by getting treatment quickly.

"As soon as someone is HIV positive they should get on antiretroviral therapy right away," said Kates, who wasn't involved with the new report.

She said people in the south face a "perfect storm" of problems with healthcare access and broader socioeconomic issues, including stigma and discrimination, poverty, lower education levels, greater numbers of uninsured, and higher rates of non-HIV sexually transmitted infections.

"These data tell us there is hope for making a bigger difference in the epidemic, but we need to provide access and treatment to those who remain at greatest risk," Mermin said.