Investments in prevention efforts in some countries were starting to pay off, but far more was needed, according to this year's AIDS epidemic update report, published Monday.

AIDS has killed more than 25 million people since it was first recognized in 1981, making it one of the most destructive epidemics in history. An estimated 3.1 million people died from AIDS-related illnesses last year, and another 4.9 million people became infected with HIV, the virus that causes AIDS.

Only a handful of countries have made serious efforts, the report said. Worldwide, less than one in five people at risk has access to basic prevention services, and only one in 10 infected HIV has been tested and made aware of the infection, the report said.

Fewer New Infections

For the first time, though, there was evidence that increased efforts to combat the disease over the last five years have resulted in fewer new infections, UNAIDS chief Peter Piot said.

Previous improvements -- such as in Senegal, Uganda and Thailand -- were considered exceptions, but falling infection rates among youths or pregnant women in several countries indicated a positive, overall trend.

"Now we have Kenya, several of the Caribbean countries and Zimbabwe with a decline," Piot said. "If you see a decrease in prevalence in young people, that reflects a decrease in recent infections." Infection rates among pregnant women are also considered a good indicator of what is going on in the population.

Many of the recent decreases were attributed to safer sexual behavior, Piot said.

"People are starting later with their first sexual intercourse; they are having fewer partners; there's more condom use," Piot said. "It's a consistency now that's a really good sign."

Dramatic Drops in Prevalence

For years, sub-Saharan Africa and the Caribbean have been the two regions with the highest rates of HIV infection.

The epidemic has continued to intensify in southern Africa, as well as in Eastern Europe and in Central and East Asia. Five years ago, one in 10 new infections were in Asia. Today it is one in four or one in five.

Piot said he believed, however, that more countries were improving. "We see similar (positive) trends in countries in East Africa, but the evidence was not good enough to put in the report," he said.

The most dramatic drops in prevalence were among pregnant women in urban Kenya, where in some areas infection rates dropped from about 28 percent in 1999 to 9 percent in 2003.

In the Caribbean, declines were evident in Barbados, the Bahamas and Bermuda, Piot said. Urban Haiti registered a drop in the number of cases, but Piot cautioned that figures there may have been affected by an increase in AIDS-related deaths.

In southern Africa, Zimbabwe showed the most improvement. HIV prevalence among pregnant women in the capital, Harare, declined from 35 percent in 1999 to 21 percent in 2004, Piot said. Zimbabwe, which was among the region's countries first hit by the virus, began intensive prevention programs earlier than others.

Rapid Scale-Up in Scope

"This year's epidemic update shows that HIV prevention programs are working, in pockets. We need to make it work at the world level," said Purnima Mane, UNAIDS director of policy, evidence and partnerships.

"A rapid scale-up in the scope of HIV prevention programs is urgently needed," she told a London news conference.

Dr. Jim Kim, HIV chief at the World Health Organization, also said the global effort had gained momentum.

"Everyone is sort of jumping on the bandwagon," he said. "There's been a fundamental change, even in the past one year, in all the efforts in HIV."

The recent availability of HIV treatments in the developing world gave new energy and hope in fighting AIDS, Kim said. With drugs attainable, more people are open to being tested for the virus, which is crucial for prevention efforts, he said.

Drug treatments last year prevented about 300,000 AIDS-related deaths, the report said.

Spur for Rich Countries

In 2004, slightly more than US$8 billion (€6.85 billion) was spent on tackling HIV in the developing world, compared with US$6 billion last year -- far short of what the UN says is needed.

UNAIDS estimated US$15 billion (12.8 billion) would be needed next year, though only US$9 billion (€7.7 billion) has been pledged to the effort.

AIDS activists called on rich countries Monday to dramatically increase funding to fight the disease in poor nations.

"These figures ... must be the spur for rich countries to turn their promises into action," said Simon Wright of London-based ActionAid.

Asia was among regions where HIV infection rates expanded the most, with China, Papua New Guinea and Vietnam registering significant increases. There were also alarming signs that Pakistan and Indonesia could be on the verge of serious epidemics, the report said.

In both Asia and Eastern Europe, intravenous drug use and commercial sex were the main reasons cited for the increases.