A decade ago, widespread adoption of safer-sex practices by gay men and new drug therapies had nearly stabilized the US AIDS epidemic, with death rates dropping by two-thirds and new HIV infections decreasing. Now, a new trend is eroding that progress.

Use of methamphetamine, or crystal meth, in the gay community has spurred an increase in unprotected anal sex that alarms activists and health officials. "The bottom line is that crystal meth is a dangerous drug" and "also increases HIV risk," said New York City Health Commissioner Dr. Thomas Frieden.

Addictive and easily available, meth's effects include impaired judgment, loss of control, a voracious sexual appetite and a sense of invulnerability. Experts say the combination creates a perfect environment for the spread of HIV.

Gay bathhouses - where drug use is widespread, albeit prohibited - are the front line of the problem. Some patrons stay high for an entire weekend and engage in sex with dozens of partners. However, even if bathhouses were shut down or it were possible to enforce regulations requiring condom use, crystal meth would still fuel anonymous sex encounters arranged through the Internet, said AIDS activist Peter Staley, a recovering crystal user. Recently, Staley personally funded a $6,000 anti-meth ad campaign in New York.

Although there is a lack of hard data connecting crystal to HIV, studies have found that gay men on meth are less likely to use condoms and more likely to have multiple, anonymous partners. They are more likely to contract STDs and to be infected with HIV.

New York City officials plan to launch a $300,000-plus program and task force to fight crystal meth use in the gay community this summer, but Frieden pointed out that "one of the real challenges is that we don't have a treatment for it," aside from support groups such as 12-step programs.