BARCELONA, July 7 -- The AIDS pandemic will cause a decline in life expectancy in 51 countries in the next two decades, a demographic effect essentially without precedent in modern times, according to a study released here on the opening day of the 14th International AIDS Conference.

Seven countries in sub-Saharan Africa now have average life expectancies under 40 years. In tiny Botswana, the hottest of AIDS hot spots, life expectancy is now 39 years, instead of the 72 it would have been without the emergence of AIDS.

By the end of this decade, 11 countries in the region will have life expectancies of less than 40 years, a level they have not experienced since the end of the 1800s, according to Karen A. Stanecki, a demographer at the U.S. Census Bureau, where the calculations were made.

"The AIDS pandemic is dramatically changing the demographic makeup of African countries. Unfortunately, many . . . are only beginning to see the impact of these high levels of HIV prevalence," she said.

The falling life expectancy reflects not only the death of people in young adulthood, but also an increase in infant mortality.

AIDS is eroding decades of increasing child survival, the demographers found. Zimbabwe and South Africa each have higher child mortality rates now than in 1990. In Botswana, Zimbabwe, South Africa and Namibia, more infants will die from human immunodeficiency virus (HIV) infection in 2010 than from all other causes, according to the research, which was funded by the U.S. Agency for International Development.

Longevity is also in decline in some nations in the Caribbean (the region second only to Africa in HIV prevalence). In Haiti, life expectancy is now 51 years instead of 59; in the Bahamas it is 66 instead of 74.

In Africa, about 55 percent of infected people are women, and the number of female cases is increasing. Among teenagers, girls are more likely to be infected than boys. In a survey in the Kenyan city of Kisumu, for example, the rate of infection among teenagers ages 15 to 19 was 23 percent in females, while it was 3.5 percent in males.

The increasing likelihood that AIDS will kill more women than men has potentially worrisome implications. "Current evidence indicates that older men are infecting younger women, who then go on to infect their partners, particularly through marriage. This vicious cycle could result in even higher HIV infection levels," Stanecki wrote.

Noting similar statistics at a pre-conference press briefing yesterday, Stephen Lewis, U.N. special envoy on HIV/AIDS in Africa, said, "This pandemic has become a war on women. AIDS has become the ultimate symbol of gender inequality."

Lewis predicted that in a decade or so "we're going to have a demographic rupture. . . . We're going to have all kinds of men without partners, wandering the landscape on a continent where there is already substantial instability."

The AIDS conference, which opened yesterday and will end Friday, is the largest one ever, with about 15,000 delegates, including journalists and commercial representatives. The last conference, two years ago in Durban, South Africa, had just under 10,000.

The U.S. delegation is headed by Health and Human Services Secretary Tommy G. Thompson, who will address the gathering on Tuesday. At a news conference yesterday, he said the United States is "committed to the fight against global HIV/AIDS. We want to serve those most in need, and we're ready not just to discuss and learn, but to act."

He noted that the Bush administration has provided more money to fight AIDS overseas than any previous administration, including that of former president Bill Clinton, who will speak at the conference's closing ceremonies.

In other data released yesterday, figures from 25 states suggest the number of new cases of HIV infection reported every three months in the United Statesis at 1998 levels. Between 1994 and 1998, the number of new cases fell by 24 percent.

However, it is difficult for two reasons to know whether that prolonged plateau represents the current state of the nation as a whole. The count is only complete through 2000. More importantly, California, New York and Florida, the three states with the largest number of HIV cases, aren't in the sample. They were not included because when the 25-state survey began in 1993, those states didn't require that new HIV patients be reported to public health authorities either by name or by a number-coded identifier.

Hidden in that seemingly stable picture, however, is evidence of a mini-epidemic of HIV infection in black women, and of continual risky behavior in many gay men that could potentially send the epidemic curve upward again. From 1994 through 2000, 27 percent of new HIV infections in the United States were acquired through heterosexual contact. In the last two years of that period, however, HIV diagnoses among heterosexuals grew by 10 percent. The biggest growth was among black women, who accounted for about half of all cases of HIV infection acquired heterosexually.

"Black women are suffering a highly disproportionate toll in the epidemic now," said Ronald Valdiserri, deputy director of AIDS prevention at the Centers for Disease Control and Prevention.

About 43 percent of infections in the last half of the 1990s occurred in gay or bisexual men. At that time, CDC epidemiologists conducted a survey of young gay men in six American cities. The men, all under 30, were interviewed at dance clubs, health clubs, bars and community centers. About 10 percent were HIV positive, but few of them knew it, and many believed they weren't at high risk.

Among the black men who were infected, 91 percent were unaware; among Latinos, 70 percent, and among whites, 60 percent. Slightly more than half of the entire group of infected people had either never been tested for AIDS or hadn't been tested in more than a year.

In the group of infected men who had been previously unaware, half reported having engaged in unprotected anal intercourse -- an extremely high-risk activity -- in the previous six months. Asked why they did not use a condom, about half said they were relying on a previous negative blood test from either themselves or their partner to convince them they weren't at risk for getting the virus.

FAIR USE NOTICE: This page contains copyrighted material the use of which has not been specifically authorized by the copyright owner. Global Action on Aging distributes this material without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes. We believe this constitutes a fair use of any such copyrighted material as provided for in 17 U.S.C § 107. If you wish to use copyrighted material from this site for purposes of your own that go beyond fair use, you must obtain permission from the copyright owner.