Imagine a time and place where most people die before they reach 30, where no one has the strength or the money even to hold funerals, where everyone is hungry and many are starving because there are no able-bodied adults to work in the fields. This might sound like a description of medieval Europe in the time of the plague, but in fact it may, in a few years, be a description of the state of large parts of the world, ravaged by AIDS.

Yet it seems reprehensible, particularly for Americans, to declare hopelessness on behalf of people dying of a treatable disease. Hopelessness is only an easy way out, and it is far from justified.

The current tools for fighting HIV, though hardly perfect, could begin to stanch the pandemic. Therapy has reduced mortality by 90 percent in places where antiretroviral drugs are widely administered. Brazil's attempt to provide nationwide prevention and treatment has already led to significant declines in new infections there -- and, as a collateral benefit, has reduced the number of people newly infected with tuberculosis, the world's other horrifying pandemic.

Of course, Brazil is a relatively wealthy nation, while most of the places severely afflicted with AIDS are impoverished. They lack not just money to buy antiretroviral drugs for themselves but also clean water, food, electricity, serviceable roads and medical facilities and expertise. To many authorities in international health, comprehensive programs for AIDS treatment and prevention have seemed unimaginable in such places, the very places that need them most.

Haiti is one of those. It is the poorest country in the Western Hemisphere and has the hemisphere's largest burden of AIDS. But recently it has also become something like a laboratory for the world, the site of what has so far been a successful effort to bring AIDS treatment and prevention to a mountainous, deforested, mostly unelectrified and famished region -- served by roads that resemble dry riverbeds -- known as the central plateau.

The effort is being led by a relatively small public charity with headquarters in Boston, Partners in Health, which was founded by Tom White, a wealthy philanthropist, and Paul Farmer, an infectious disease specialist at the Brigham and Women's Hospital and a professor of medicine and medical anthropology at Harvard University.

Over the past 20 years, PIH has created a system of public health in the poorest section of Haiti's central plateau, providing free medical care, vaccinations and a broad range of health-related measures that have vastly improved local nutrition and housing and supplies of potable water.

Now, in collaboration with the Haitian Ministry of Public Health, PIH is attempting to expand its system, including its already existing program for treating and preventing AIDS, throughout about one-eighth of Haiti. The money for expanding AIDS treatment and prevention -- about $2.5 million a year -- comes from a grant to Haiti made by the Global Fund to Fight AIDS, Tuberculosis and Malaria, an international organization financed by wealthy governments and foundations.

To fight AIDS effectively, PIH believes, it must identify and treat all sexually transmitted diseases and all cases of tuberculosis (HIV and TB share what's been called "a noxious synergy"; that is, an active case of one tends to make a latent case of the other active, too.) They must also pay special attention to the overall health of women and try to prevent the transmission of HIV from mothers to babies. And, finally, they have to employ various other prevention measures and provide antiretroviral therapy.

PIH and its Haitian colleagues are now treating about 1,000 AIDS patients and are providing nutritional and social support and testing to another 8,000 who are infected with HIV but don't yet need therapy. The costs are remarkably low by international standards -- about $400 a year for each of the 8,000 not yet being treated with antiretroviral drugs and about $700 for each of those in therapy (and that figure will soon fall, along with drug prices, by about $150).

About 800 people are working on the expansion. Only four are American; the rest are Haitian. Sixteen are doctors. Most of the rest, about 700, are community health workers, Haitians of the peasant class, some of them former patients of PIH. All have been trained -- they receive further training from the professional medical staff at least once a month -- to recognize the symptoms of a range of diseases including AIDS and also the complications of HIV and the side- effects of anti-AIDS drugs.

Each health worker tends to the needs of about six patients. They bring the medicines and watch as the patients take them -- a technique for minimizing drug-resistance that has worked well in tuberculosis control. They also provide aid, comfort and health education to the patients and their families.

The community health workers all receive salaries. The sums would be laughably small in a place like New York, but they are substantial in the central plateau, where an official unemployment rate of 70 percent probably understates the case. And given the fact that most Haitian peasants have large extended families, the salutary effects of those wages are undoubtedly magnified. This project has just started and is still expanding. Since 1988 PIH has used an almost identical system for treating TB in the central plateau, and in all those years has not lost a single patient from its catchment area to an uncomplicated case of that disease. So the prospects seem good for AIDS treatment and prevention in Haiti's central plateau.

Of course, there is no way of knowing for sure that versions of this project would work in other parts of the world -- not unless and until earnest attempts are made. But the basic principle, heavy reliance on community health workers, seems transferable; most poor countries lack decent health systems, but most, like Haiti, have an abundance of potential health workers. High-tech AIDS testing is desirable but not necessary in the initial phases of a project. PIH has recently acquired the equipment to measure the health of patients' immune systems, but for many years they treated AIDS successfully without it.

Partners In Health has a record for creating replicable solutions to complicated health problems. In 1995, the organization began a small project in a periurban slum of Lima, Peru, a project to treat a dreadful form of drug-resistant tuberculosis. The strategy they came up with is now being used in 16 different countries.

As for treating AIDS, PIH has imported the general techniques it uses in Haiti to a project for treating underserved patients in various rundown parts of Boston -- with notable success so far. Those techniques have been watched closely by various African countries, governments and international organizations that have launched pilot programs for treating and preventing AIDS; in several places pilot projects are being scaled up.

It's never hard to find reasons for skepticism. Many people acquainted with PIH's work have imagined that they do things no one else can do, that their success depends on the dogged brilliance of Paul Farmer. But much of the work in Haiti goes on without Farmer now. It often takes a person of dogged brilliance to show the rest of us what's possible. The same could be said of the organization he founded.

Worldwide control of AIDS would not be easy. It would not be accomplished in a decade, or even in two decades. But PIH and its Haitian partners have already made it hard to argue that control is impossible. Thanks to this growing effort in one of the world's poorest countries, the rich nations of the world now face a choice -- a choice about the kind of planet future generations will inherit.

Tracy Kidder is a Pulitzer Prize- winning author whose most recent book is "Mountains Beyond Mountains: The Quest of Dr. Paul Farmer, a Man Who Would Cure the World" (Random House).