The stigma surrounding AIDS is a key reason why the South has half of all new cases in the United States, although it has only a little more than a third of the country’s population, according to the federal Centers for Disease Control and Prevention.

The South also has the highest death rate due to HIV.

“It’s not a new trend,” said J. Michael Kilby, professor of medicine and chief of infectious diseases at the Medical University of South Carolina.

“It’s something that we’ve known about for years, but for some reason the public has been a little slow to pick up on it. The Deep South in general has had the most HIV cases for a long time now. We’re one of the states driving this epidemic in the United States.”

Scientists, diplomats, politicians and more are meeting in Washington, D.C., this week for AIDS 2012, the 19th annual international AIDS conference.

South Carolina ranks ninth in the nation in HIV/AIDS cases, according to the Kaiser Family Foundation’s December 2010 fact sheet. Nearly 15,000 men and women are estimated to be living with the infection, and more than 9,000 of them are ages 25-49.

“Really the main issues are poverty, discrimination, stigma, lack of education, and poor access to health care and preventive care,” said Ashley Redmond, director of the Ryan White Program and Wellness Center at Roper St. Francis Healthcare. “Testing, outreach and education are the keys.”

When the center asked people in the community about their perception of HIV/AIDS, it found that many didn’t hear much about the disease, “yet our numbers are still growing, so it’s up to us as a program that serves this community ... to get the information out there,” she said. “We need to be able to get into the schools, to get into the churches.”

The center held an HIV/AIDS clergy symposium to help create discussions, she said.

“A lot of our population is African-American and they are so tied with their churches that when they receive news of their HIV diagnosis, they don’t feel they can talk to anybody,” Redmond said. “We’re working with clergy to start these conversations with their congregations.”

Carolyn McAllaster, director of the Southern HIV/AIDS Strategy Initiative, said one reason HIV is so prevalent in the South is that people don’t get tested. Nearly 20 percent of those who are HIV positive don’t know it, according to Kaiser.

“We see sad cases here all the time of people who present with blindness or meningitis or pneumonia, and that’s the way they get diagnosed with HIV/AIDS,” Kilby said. “In an ideal world, they should have been diagnosed years before that.”

Those who earn less than $10,000 a year are three times more likely to be infected with HIV than those who make more than $50,000, according to the CDC.

“HIV is clearly a disease of poverty,” said Michael Saag, director of the Center for AIDS Research at the University of Alabama at Birmingham. “And there is a lot of poverty in the South.”

Once infected, poor people face steep obstacles to adequate care. They often have no health insurance and little money for medicine, tests and doctor’s appointments.

African-Americans have been hit hardest. They account for half of men, and nearly three-quarters of women, in the South whose HIV infections are newly diagnosed, according to the CDC.

Rates are especially high for gay black men in the South; a 2011 study by researchers at the Florida Department of Health calculated that one in five were infected with HIV.

Researchers say that African-Americans in the South are especially likely to see homosexuality as immoral. In response, gay black men in the South often live on the “down low,” leading ostensibly straight lives with girlfriends and wives while having sex with men.

“In the African-American community, men who are gay are more likely to hide their sexual activity,” said Saag, who also directs a HIV clinic in Birmingham. “So it’s more common for the virus to spread from gay men to heterosexual women.”

Because so many people in the South do not get tested for HIV, many who are infected don’t know it, and are likely to keep infecting others.

A significant number of people diagnosed with HIV simply don’t get treatment, even though state and federal government aid often provides medicine for those who can’t pay.

Throughout the South, sex education and HIV-prevention education tend to be limited, with most states and counties relying on abstinence as the touchstone. In general, state public health departments in the region are badly underfunded and have a hard time meeting the varied needs of people who have HIV or are at risk of being infected.

Patients in the South often live far from doctors and specialists and lack transportation to get to them. In South Carolina, one in four of those with HIV live in rural areas, as do four in 10 in Mississippi, by far the highest percentage in the country. Many of these patients can’t afford a vehicle and have trouble getting to doctors, who are often 100 or more miles away.

“We can get creative with providing transportation by van or bus or whatever it takes to get people in from smaller towns,” Kilby said.

David Kohn, a freelance writer for The Washington Post, contributed to this report. Reach Brenda Rindge at 937-5713 or www.facebook.com/brindge.