Cross posted from Nature’s Spoonful of Medicine blog. Written by Elie Dolgin.

The death toll from AIDS has topped 25 million people, but new infections are dropping sharply, according to a report released yesterday by the Joint United Nations Programme on HIV/AIDS (UNAIDS) and the World Health Organization (WHO).

First, the bad news: according to the new report, titled AIDS Epidemic Update 2009, last year some 2.7 million people became infected with the virus. That brings the total number of people living with the disease to around 33.4 million worldwide.

The good news is that this rate of new HIV infection has been reduced by 17% over the past eight years. Since 2001, HIV incidence has fallen by 15% in sub-Saharan Africa and 25% in East Africa. In South and South East Asia, HIV infections declined by 10% in the same time period.

The report also concluded that the number of AIDS-related deaths has dropped by more than 10% over the past five years. That change, it says, is due in large part to more widespread availability of life saving anti-retroviral treatments.

The report’s rosy glow is no license for complacency, however. “This is a sign that HIV infection prevention efforts are making a difference, but we’re still not moving fast enough to break the trajectory of the virus,” UNAIDS deputy executive director Paul De Lay said at a press conference.

For example, a new case study published in this month’s issue of the journal AIDS describes a particularly nasty strain of HIV that killed a previously healthy 20-year-old within 6 months of infection, even though the virus didn’t show up on standard antibody tests. So, while infections and deaths may be on the decline overall, clinicians and researchers need to stay vigilant to detect the next trick up HIV’s sleeve.

“It is now a morel imperative that we sustain and strengthen the global response to this epidemic,” Teguest Guerma, acting director of the WHO’s HIV/AIDS department, said at the press conference.

Image: UNAIDS