MASHAI, Lesotho >> At a clinic in the mountains, reached only by crossing a churning river in a rowboat, Dr. Paul Young, a pediatrician raised in the housing projects of Savannah, Ga., soothed a fussy baby. She stared at him, fascinated, as he made soft popping sounds with his lips and listened to her heart through a stethoscope.

“I used to be afraid to look at the babies’ test results,” he said after examining a bunch of children, who were born healthy despite having HIV-positive mothers. “But now, most of them are negative.”

Young, 33, and the nurses he trained here have persuaded many pregnant women to get tested and take the drugs that prevent them from passing the disease to their newborns. It is all part of a charitable effort he joined in 2008 for $40,000 a year and the chance to work in this AIDS-afflicted country, which has just one pediatrician in its entire government health system.

“If this was the last thing I did, if this was the only job I ever had in life, I would have served my purpose,” he said.

Young represents the surging interest of young Americans in combating the deadly epidemics ravaging the world’s poorest countries, fueled in part by the billions of dollars that the American government, the Bill & Melinda Gates Foundation and other organizations have poured into international health in recent years.

Across sub-Saharan Africa, an extreme shortage of health workers remains a critical barrier to fighting illness. The region bears a quarter of the world’s burden of disease, but has only 3 percent of its health care workers, according to the World Health Organization.

Public health experts say efforts like the one involving Young have proved particularly useful on a continent that sorely needs pediatricians, surgeons and other specialists to train African doctors and nurses in the field.

And demand for such opportunities is rising. More than 70 universities in the United States and Canada now offer formal academic programs in global health, most of them developed in just the past five years, according to the Consortium of Universities for Global Health.

“Today’s students really want to make a difference in the world,” said Michael H. Merson, director of Duke University’s Global Health Institute. “They have a passion for sacrifice and service. It reminds me of the ’60s.”

The children of powerful politicians are part of this new generation of global health enthusiasts. Vanessa Kerry, 34, a Harvard-trained doctor and the daughter of Sen. John Kerry, D-Mass., is advocating a Peace Corps-like federal program that would send American doctors and nurses to work and train health workers in developing countries.

And Barbara Bush, 29, a daughter of former President George W. Bush, co-founded the nonprofit Global Health Corps, which this year sent 36 college graduates from eight countries to work with nonprofit groups, mostly in Rwanda, Burundi, Malawi and Uganda. More than 1,000 people applied for the yearlong fellowships.

The Pediatric AIDS Corps that sent Young here, largely financed by the Bristol-Myers Squibb Foundation and the Baylor College of Medicine, never advertised for applicants after the first class of doctors was recruited in 2005. Word of mouth produced far more highly qualified physicians from universities all over the United States than the project could ever hire.

In addition to the salary, the program paid down as much as $40,000 of the doctors’ educational debt for each year of service — making it possible for Young to join, though he owed $170,000 after his undergraduate and medical studies. His mother was an assembly-line worker, and in hard times the family relied on Medicaid. Young himself never had a steady pediatrician as a child.

With a laugh, he said that his friends back home asked him if he had running water or used an outhouse in Africa. “We’re not roughing it here by any means,” he tells them. He drives a 10-year-old Opel Corsa, but lives in a pleasant town house in the sleepy capital, Maseru, with wireless Internet and a housekeeper who comes twice a week. For the first time in his life, he has gone skiing — in Lesotho’s breathtaking mountains.

But it is the work that gives the job its meaning, the doctors say. Lineo Thahane attended Princeton University and got her medical degree at Washington University in St. Louis. It was a 2003 rotation in Lesotho’s main public hospital during her residency — when children were still dying of AIDS for lack of antiretroviral treatment — that made her want to return to Africa. Her parents were both from Lesotho, but she was born and raised in the suburbs of Washington, D.C.

Thahane, 35, joined the first crop of Pediatric AIDS Corps doctors in Lesotho, and now helps her mother, Dr. Edith Mohapi, 64, who for 20 years managed pediatric outpatient services at Arlington Hospital in Virginia, to run Baylor’s pediatric HIV programs in Lesotho.

“I felt, ‘This is where the need is,”’ Thahane said.

Over the past five years, the corps has had 50 to 60 doctors working in Lesotho, Swaziland, Malawi and Botswana. The hospitals and clinics they supervise now care for more than 50,000 HIV-positive children, Baylor estimates.

The project’s impact should also last beyond its financing, which ends in June. The 128 doctors who served in the corps over the last five years trained about 3,000 African professionals, who will carry on. And in July, Baylor will start another project with 32 pediatricians to work on a broader array of diseases.

Dr. Grace Phiri, an overworked Malawian who has been the only pediatrician in Lesotho’s government service for most of the past 17 years, said the arrival of 10 AIDS Corps doctors in 2006 — just as AIDS drugs for children were becoming more widely available — drastically improved the survival chances of HIV-positive children.

Until 2005, not a single child with AIDS was on publicly financed antiretroviral therapy in Lesotho.

“Every morning, I had to check on who is alive and who is not alive,” she recalled. “So many passed away. Most of those dying were under the age of 2. It went on for years. You see, in the ’90s we didn’t even have enough kits for HIV testing.”

More than 6,500 children in Lesotho, a country with a population of 2 million people and the world’s third-highest rate of HIV infection, now receive the lifesaving medications. While that is progress, it is still only about a quarter of those in need of treatment, according to UNAIDS, the U.N. AIDS agency.

© 2011 The New York Times Company