Manuel Faustino Gomes, 15, lost both his parents during Angola's long civil war and spent years as a child of the streets, scrambling to survive in this battered city.

Yet on at least one score, Gomes, who has a baby face and a picture of Britney Spears wearing a lacey black bra by his bed, has been fortunate compared to boys in similar circumstances across southern Africa: He has come of age sexually in a country where the HIV infection rate has been relatively low.

Decades of warfare trapped Angola in a kind of medical time warp. Borders were closed. Civilians moved cautiously or not at all. And the disease that has ravaged this continent more than any other largely bypassed Angola.

The estimated HIV infection rate for Angola remains under 10 percent for non-elderly adults, less than half of the rate in neighboring Congo or Zambia, and about one-fourth the rate in Botswana, which despite being among the region's most prosperous and peaceful countries, has an HIV rate estimated at 38 percent.

The danger, humanitarian groups say, is that the situation in Angola is already changing quickly. Two years of peace, combined with the social dislocation, poor health and low education levels created by war, have put the country on the path to reach the infection rates of its neighbors in just a few years.

Adding to the danger are the opening of new trucking lanes and the surge of hundreds of thousands of refugees returning from camps in countries with far higher HIV rates. In addition, soldiers from both sides of the conflict are resettling across Angola, and bringing infection to areas where previously it was rare.

Sudden jumps in infection rates already have been recorded in Luanda, the capital, among prostitutes and pregnant women. A nationwide study due to report results in several months is expected to show an increase among the entire population.

"All of the factors are there," said Laurie Bruns, an expert on HIV in southern Africa for the U.N. High Commissioner for Refugees. "It's kind of a risky mix."

The relatively low infection rates have kept Angola from receiving as much in international funding and attention as some neighboring countries. All but two of the 15 "focus countries" for President Bush's $15-billion initiative to combat HIV and AIDS are in Africa, but Angola is not on the list. Even with the current rates, UNICEF estimates that 500,000 Angolans are infected.

In Angola, a country of 14 million people, 70 percent of the population is younger than 25 years old. Young adults and teens are considered among the most vulnerable and the most likely to spread HIV to others.

The rate is especially low in the interior provinces such as Huambo, where the fighting was most intense.

Huambo, a former rebel stronghold, is now surging with new activity. The streets still have deep craters, and many of the buildings are missing roofs or walls lost to the war. But the city has a functioning motorcycle factory, a new hotel and at least one aspiring Internet cafe. There is also a growing freedom of movement, both within the city and beyond its borders as minefields are cleared and repairs are made to highways and bridges.

Gomes lives at Okulissanga, a home for orphaned street children in Huambo. Okulissanga operates on the edge of the city, in an area booming with new housing construction. The boys sleep four to a room in crude barracks beside a roofless, bullet-pocked building that once housed a dairy. Gomes and others walk into the city center to meet girls and other friends.

Many of the boys said they know about condoms and have easy access to them through the nurse at Okulissanga, who hands out nearly 600 a month. Gomes said he always uses one during sex with his 16-year-old girlfriend, but many of his friends do not.

"They say it's not nice to do it with a condom," he said.

Studies show that Angolans start having sex at a younger age and have more partners than others in southern Africa. The average age for a girl's first sexual encounter is 14. And these young teens are prized by older men who exchange sex for cell phones, blue jeans or, in rural areas, such basics as seeds or a ride to the market.

"HIV here is probably going to explode because of this informal exchange sex," said Melanie Luick, an AIDS expert with the UNICEF office in Luanda.

As the infection rate lags behind the region, so does the medical response and the public understanding of AIDS.

Most of the public health system was destroyed during the war, leaving an acute shortage of hospital beds and medication, especially of the antiretroviral drugs key to treating AIDS. There are only 12 HIV testing and counseling centers in Angola. And compared to other southern African nations, Angola has few billboards or public education campaigns devoted to preventing spread of the disease.

The messages, by contrast, are explicit at Okulissanga, which has weekly HIV education classes that are open to the general public in Huambo.

At one recent class, a drama group comprised mostly of boys from the program performed a skit about HIV. A 17-year-old girl tore open a wrapper, pulled out the condom inside, then rolled it onto a model of a penis held at the midsection of a teenaged boy.

"If you want to live," the group said in unison, "use a condom."

But six boys interviewed after the class all shook their heads vigorously when asked whether they knew of anybody with HIV or AIDS. They agreed that most sexually active boys they knew did not use condoms regularly. And several said that girls resent it when boys suggest they do, especially within a steady relationship, because of the stigma associated with AIDS.

"I try and I insist, and if she still says 'No' . . . ," said Ezequiel Chilena, 17, his voice trailing off as he lowered his eyes. "And maybe the next time I'll try to convince her again."

Another boy, Martinho de Lima, 16, has been at Okulissanga for three years. But when he had his first sexual encounter in January, de Lima said, he had not yet attended an HIV awareness class. The couple did not use a condom.

"We didn't know," he said.

Maria Lonor Manuel, 17, holds a condom during a drama at a home for boys in Huambo to educate Angolans about the dangers of HIV and AIDS.Manuel Faustino Gomes, 15, who lives at a home for street boys in Huambo, said he always uses a condom during sex but that many of his friends do not.