ATLANTA (AP) — Americans have become complacent about safe sex. Revolutionary new drugs have allowed HIV-infected people to live longer. A new generation of gay men entered their 20s without the memory of the early days of AIDS devastation.

Health officials saw the signs and warned that AIDS — after declining for a decade — could make a comeback in this country.

Last week, new figures showed the predictions were right — AIDS diagnoses increased for the first time in 10 years.

Many Americans felt that AIDS had become an African epidemic, that the disease was under control here. That complacency is one of the main reasons that new HIV infections have been creeping up lately, especially among gay men in large cities.

“There needs to be a lot more attention paid to the HIV epidemic in the United States,” said Dr. Jim Curran, dean of Emory University’s Rollins School of Public Health, and a former AIDS director with the Centers for Disease Control and Prevention. “People need to realize there’s still no cure and no vaccine. Our greatest enemy in HIV prevention is ... complacency about our epidemic here.”

Last year, 42,136 new AIDS cases were diagnosed in the United States, up 2.2 percent from the previous year. The number of gay and bisexual men infected with HIV was up for the third year in a row after a decade of declining numbers.

Health officials say prevention efforts have stalled, and they are changing their strategy from one of preventing new cases to counseling those who already have HIV in an attempt to get them to stop spreading it.

The CDC estimates 850,000 to 950,000 Americans are living with HIV, and nearly 385,000 of those have full-blown AIDS.

“I don’t think we’re losing the war, but we’re certainly not finished with the war,” said Dr. Ronald Valdiserri, a CDC deputy director.

Since 1990, the U.S. HIV infection rate has been constant at 40,000 cases a year. The country is in danger of failing to meet its goal of cutting that number in half by 2005. Not meeting the goal will result in 130,000 more people infected with HIV by 2010 and a health care cost of $18 billion, researchers estimate.

New threats have emerged: up to 15 percent of new HIV cases in the country are believed to have drug-resistant strains of the virus.

Other statistics have indicated an increase of risky sexual behavior. Syphilis outbreaks have erupted in recent years among gay men in America’s largest cities.

The problem, and the answer, health officials say, lies in prevention. The new generation of sexually active Americans do not remember the devastation of the AIDS epidemic. AIDS-era veterans have suffered burnout from years of good-health messages and safe-sex practices. There’s also a lack of concern because of life-extending drugs. Some gay men use the term “pill fatigue” to describe what happens when someone tires of taking HIV medication for many years.

“Part of it is complacency, part of it is indifference — people may know it and they just don’t care,” said Terje Anderson of the National Alliance of People with AIDS. “Part of it is fatigue — guys have been trying to stay safe for 20 years, how do you keep doing it? At a certain point people are losing their ability to do that and it’s very troubling.”

In April, CDC director Dr. Julie Gerberding, noticing current efforts had stalled, announced a change in the country’s HIV prevention strategy. The new focus is on stopping HIV-positives from transmitting the virus to others.

The country’s previous strategy focused on prevention, by addressing potentially risky behavior in uninfected people.

The new strategy has been criticized by AIDS activists, who worry that it focuses too much on people who already have the virus and not enough on people at risk. AIDS groups also are worried they will lose vital funding to pay for the new effort.

Overall, the CDC initiative is a good approach, but prevention campaigns cannot neglect the power of small-group and community-level interventions, Anderson said.

“You’ve got to recognize the social environment risk happens in,” Anderson said. “There’s a shared responsibility for prevention and the recognition that (HIV) positives and negatives need a whole range of services. We need an approach that adds to both, not takes away from one.”