THE SMALL AD on the No. 88 bus that rumbles through Cambridge and Somerville is easy to miss: 1.4 million treated for hiv/aids, 41 million more to go. For years, AIDS researchers pretty much ignored that message. Their job was to find new drugs, not to deliver them. But, among the scientists who gathered in Boston recently for the 10th Conference on Retroviruses and Opportunistic Infections, that parochial attitude is clearly out of date.

Nearly 4000 researchers — including immunologists, molecular biologists, and pharmacologists — filled the Hynes Convention Center earlier this month, and for the first time, the global, as opposed to domestic, AIDS epidemic occupied a prominent place on the conference’s agenda.

Not that there isn’t trouble here at home. Seven years after these same scientists helped produce the life-extending cocktail of AIDS drugs, new problems are emerging. Instead of worrying about pneumonia and blindness, people with AIDS now cope with liver disease and heart attacks. On top of that, the three-drug combination that has saved so many lives no longer does the job for many. Drug resistance is the other shoe, and it’s dropping.

The scientists at the conference addressed all those typically front-burner domestic issues, but it would have been difficult for them not to turn their attention overseas as well — especially after Zinhle Thabethe, a slight, young South African woman, gave them a powerful look into the face of the African AIDS epidemic. Thabethe came to Boston with Sinikithemba Choir, a group of HIV-positive men and women from Durban, who performed their flawless harmonies during the event. Wearing her red, beaded isicholo, a wide, flattop Zulu hat, Thabethe stepped up to the podium during the opening session and stole the show from the next speaker — who happened to be Bill Clinton.

In the lyrical English of South Africa, Thabethe resurrected a picture of AIDS that has all but faded from consciousness in the US and Europe — weekly funerals and the unmistakable signs of illnesses such as Kaposi’s sarcoma (KS) an AIDS-related cancer. "We have watched each other lose weight, have the dark spots of KS appear on our skin, listened to the deep cough of TB, [and] wiped each other’s tears after one of us lost a six-year-old child to AIDS," she said.

At one point, Thabethe herself lost so much weight and became so weak that she accepted her imminent death. Then, last year, she enrolled in a drug study and began getting better. Today, she carries no visible signs of her illness.

In that, she represents a tiny fraction of Africans with the disease. Most AIDS patients in the US and Western Europe can get lifesaving drugs, but despite a drop in drug prices, the adoption of simpler dosing regimens, and a mounting international-access campaign, those same drugs remain scarce in poor countries. According to the World Health Organization, in sub-Saharan Africa, less than one percent of AIDS victims are treated; less than four percent in Asia. One of the major arguments against providing the complicated therapy in what are politely described as "resource-poor settings" is that patients won’t stick to it. If AIDS patients take their drugs intermittently, they can develop and spread drug-resistant forms of the disease. Thabethe told the group that despite being unemployed and living in her mother’s home with no income, no electricity, and no running water, "I have never missed a dose ... never." In response, the quiet audience broke out in applause.

"Thank you for all you have done so far, developing treatments that are saving lives," she said, pausing to contain her tears. "And thank you in advance for what you are going to do. The word sinikithemba means ‘give us hope.’ You do that for us through your work. You give us hope — hope that we will all someday have treatment that will save our lives."

Paul Harding, an assistant in the pediatric infectious-disease lab at the University of Colorado Health Science Center, was struck by the audience response. "All these research scientists who are so stoic," he said. "They were crying."

THE NEXT MORNING, it was back to business at the Hynes. In contrast with the raucous 2002 International AIDS Conference, there were no protesters heckling Bush-administration officials, no exhibit halls full of drug-company reps, and little talk of the emerging ethical issues with overseas vaccine and therapy research. This smaller convention focused on science, not policy or politics. The drug companies’ scientists were invited; the drug-company marketers were not. A Bristol-Myers Squibb rep stood alone in the atrium outside the convention center, handing out press releases about a new drug to anyone with a conference press pass.

Even if the direct-action crowd had shown up, there were no high-level Bushies to shout down. And there was little talk of the president’s promise to increase funding for AIDS research and treatment. Most attendees had an "I’ll believe it when I see it" attitude about that. Others expressed disappointment that the money would not be channeled through the Global Fund, a year-old, well-connected project trying to increase worldwide AIDS spending. Only Bill Clinton — who has taken on AIDS as one of his post-presidency projects — spoke positively about Bush’s move. "I know there are a lot of questions about how the money will be spent," he said. "I have to say that I’m very grateful.... It’s a huge step forward."

News in the "step backward" category came from Ronald Valdiserri, of the Centers for Disease Control. He reported that, for the first time since 1996, the number of new AIDS cases in the US rose in 2001 — up one percent to 41,311. "We can’t say whether that represents a trend," he said. "We have to very carefully monitor the situation."

Two reports — one looking at gay men who met partners via the Internet and the other looking at recently released prisoners — seemed to help explain the increase. Unprotected sex was common among people with AIDS in both groups.

About 13 percent of all US HIV patients are resistant to one or more of the drugs that have been keeping them alive for the past seven years. At one of the meeting’s daily press conferences, John Mellors of the University of Pittsburgh gushed on about the "bumper crop" of promising new drugs that would begin to address this problem.

"The pipeline of new drugs has an impressive number of candidates and this is something we haven’t seen in a few years," he said. But the three scientists Mellors introduced looked a bit less excited and spoke more cautiously. One of them, Dr. Daniel Kuritzkes, of Brigham and Women’s Hospital, reported good results with an experimental drug called TNX-355. Such drugs, called "entry inhibitors," are eagerly anticipated because they stop the AIDS virus at a different stage than do existing drugs, with the goal of keeping the virus from invading healthy cells, hijacking their genetic machinery, and reproducing. The hope is that entry inhibitors will induce fewer side effects and offer a second line of treatment for drug-resistant patients. In a small test involving 30 patients, Kuritzkes’s drug reduced HIV levels significantly, and one shot of it seemed to work for several weeks. "This is a preliminary study," Kuritzkes warned, adding that his team needs to do at least two more years of research before they can say the drug is safe and really works.

In the wake of life-prolonging treatments, long-term problems of living with AIDS are beginning to emerge. Side effects spring not only from the drugs, but from survival itself. A Danish study, involving 2400 people, added evidence to previous studies linking anti-AIDS drugs and the risk of heart attack. Additionally, many AIDS patients have hepatitis and are now living long enough for it to destroy their livers. In the past, transplant wasn’t an option, but a study conducted at the University of Pittsburgh confirmed earlier reports that AIDS patients survive such operations just as well as HIV-negative people do.

On the vaccine-development front, progress is slow and somewhat unsure. Women now make up more than half the world’s AIDS patients. Anti-AIDS drugs can help prevent them from passing the virus on to their children. And researchers had promising reports on potential "microbicides" — chemicals women can put in their vaginas to prevent HIV infection. Another study found that anti-AIDS drugs seem to work as well in women as they do in men, but noted that women have unique complications, including a possible risk of osteoporosis.

WHILE THE SCIENTISTS were digesting all this, a stone-faced Dr. Srdan Matic, from the European office of the World Health Organization (WHO), brought them back to the kind of reality that faces the vast majority of people with AIDS. "I know that it is usual to start with a joke, for a speech in the US," he said, "but unfortunately, I don’t think it would be appropriate." He went on to describe an AIDS epidemic emerging in Eastern Europe, fueled, for the most part, by kids who like to shoot up. Drug users make up 70 percent of all new cases of HIV infection in the region, and 84 percent of them are younger than 30. "Cheap heroin is the drug of choice for both recreational and long-term users," Matic said.

At the same time, only about one percent of the region’s AIDS patients have access to antiviral drugs — about the same access rate as in Africa. And infected drug users tend to end up in jail rather than in treatment, he observed. The WHO supports the use of "evidence-based approaches" to address these problems, Matic said. In other words, officials must channel funds into well-tested strategies. Such strategies are emerging, and studies presented at the meeting from places such as Haiti and Soweto, South Africa, show that drug treatment is doable, even under the worst conditions.

Ann Williams, a Yale nursing professor who does HIV work in China, has been to all 10 conferences on retroviruses and opportunistic infections. Although she was heartened by word of possible new drugs, overall she found the session "sobering.... There is no suggestion that there is going to be a magic bullet. It’s just more hard work."

But that work will have a broader focus now that scientists are ready to address the epidemic on an the international level, said Andrew Pavia, a pediatric-AIDS researcher from the University of Utah. "I think people are beginning to connect the two [domestic and international] efforts," he said. "We’ve got a ways to go, but it’s no longer lip service."

Tinker Ready is a Cambridge-based health and science writer. She can be reached at tinkerr@attbi.com