SAMBAVA, Madagascar — Thirty miles outside this down-at-the-heels seaside town, Justin Betombo tends his vanilla plants and cheers the local soccer team as if he had not a care in the world. And in fact, what was once his greatest worry has been almost magically lifted from his shoulders.

In the local prosecutor’s office, a file filled with accusations that he had sodomized his 9-year-old niece has vanished.

Mr. Betombo was arrested in 2003 after the girl, Kenia, said he had savagely assaulted her. The police obtained his confession, which he later recanted, and a doctor’s certificate that Kenia had been sexually violated, rendering her incontinent and anorexic. Twice they sent the case file to the prosecutor.

There matters ended. Mr. Betombo attended one hearing in the prosecutor’s office, but Kenia’s parents say they were not told about it. The records are nowhere to be found. And Mr. Betombo walked away a free man. Kenia’s parents, distressed by what they saw as a travesty of justice, asked that her name be published, hoping that her case would set an example.

Among sub-Saharan Africa’s children, such stories are disturbingly common. Even as this region races to adopt many of the developed world’s norms for children, including universal education and limits on child labor, one problem — child sexual abuse — remains stubbornly resistant to change.

In much of the continent, child advocates say, perpetrators are shielded by the traditionally low status of girls, a lingering view that sexual abuse should be dealt with privately, and justice systems that constitute obstacle courses for victims. Data is sparse and sexual violence is notoriously underreported. But South African police reports give an inkling of the sweep of child victimization. In the 12 months ending in March 2005, the police reported more than 22,000 cases of child rape. In contrast, England and Wales, with nine million more people than South Africa, reported just 13,300 rapes of women and girls in the most recent 12-month period.

“The prevalence of child rape in South Africa goes from really, really high to astronomically high,” said Dr. Rachel Jewkes, a specialist on sexual violence with South Africa’s Medical Research Council.

Africa is not unique in its high rates of abuse. While a survey of nine countries last year by the World Health Organization found the highest incidence of child sexual abuse in Namibia — more than one in five women there reported being sexually abused before age 15 — it also found frequent abuse in Peru, Japan and Brazil, among other nations. Relatives are frequent perpetrators in Africa, as in much of the world. But this continent’s children face added risks, especially at school. Half of Malawian schoolgirls surveyed in 2006 said male teachers or classmates had touched them in a sexual manner without their permission.

The number of abuse cases is rising in South Africa, Zimbabwe, Zambia, Uganda, Kenya, Sierra Leone and other African countries, statistics show. Whether that means more children are being victimized or more are coming forward — or both — is impossible to determine, experts say.

Researchers cite various reasons that abuse is so common: poverty, which makes it harder for parents to keep children safe; a legacy of violent, oppressed societies, and cultural mores that allow offenders to escape criminal punishment, often by marrying their victims or compensating their victims’ families.

But, ultimately, said Dr. Jewkes, of the Medical Research Council, the vast gap between the status of men and boys and that of women and girls explains much of the climate of relative tolerance. “If I had to put my finger on one overriding issue, it would be gender inequality,” she said.

Increasingly, African nations are openly acknowledging the problem, partly because AIDS has made children more likely to fall ill or die from sexual abuse. Campaigns against abuse are under way in Zimbabwe, Lesotho, Swaziland, Kenya, Sierra Leone and elsewhere.

The impact is apparent in Zimbabwe, where a child rights group estimates that at least 2,000 child rape victims have died of AIDS since 1998. “Literally for the first time in Zimbabwe’s history, child abuse is no longer a taboo subject,” said James Elder, a Unicef spokesman.

That said, the response is minuscule compared with the extent of abuse, said Pamela Shifman, a child protection specialist at Unicef headquarters in New York. “We see huge numbers of girls affected,” she said. “These crimes are still treated as the fault or the problem of the victim.”

South Africa is perhaps furthest along in developing the specialized courts, medical treatment and counseling that have long been standard fare in the West. But even there, Dr. Jewkes said, appalling police work — for example, not verifying the addresses of suspects and accusers — routinely dooms prosecutions.

Beyond that, said Joan van Niekerk, national coordinator of Childline, which runs South Africa’s child crisis hot lines, children regularly complain that coping with the criminal justice system is worse than the sexual abuse itself.

Like much of the region, Madagascar, an island of 18 million off Africa’s southeastern coast, is making headway, but still falls short of even South Africa’s low standard.

Since 2000, Unicef has set up 11 child-protection teams of doctors, educators and judges to inform the public about sex abuse and assist victims. Hassan Mouigni, who leads vice investigations at the main police station in Antananarivo, Madagascar’s capital of 1.4 million, sees some results. This year, he said, the station has investigated 95 cases, compared with 40 in all of 2003.

But medical and legal authorities say the vast majority of families still hew to a tradition of accepting payment from perpetrators. The few who press charges are plunged into a criminal justice process that Mr. Mouigni calls deeply frustrating.

He can offer victims who arrive at his station little more than an officer behind a typewriter — no counselors, no video cameras to record testimony, no toy-filled rooms or friendly intermediaries. Instead, girls as young as 5 are expected to confront their tormentors face to face. Perhaps most daunting, poor families must produce at least $15 to cover investigation costs like gloves and paper for medical exams.

That was nearly enough to deter Claudine Ravoniarisoa, who appeared at Mr. Mouigni’s station one recent Thursday with her 15-year-old daughter. Wringing her hands nonstop, the girl told officers that a neighbor had raped her while her mother was hospitalized. “He destroyed my life and my body,” she said.

Image A SUSPECT GOES FREE Justin Betombo denied his niece Kenias accusation. He was freed after convincing a prosecutor that he had falsely confessed after a police beating. Credit... The New York Times

But once her mother learned of the costs, she decided to identify the perpetrator only as “Mr. X.”

“I have no money to pursue this,” she protested, while an officer tried to persuade her to do so.

In another room, Domoima Rahamtanirima pressed a case against her brother-in-law in the molestation of her 5-year-old, Menja. For two weeks afterward, Mrs. Rahamtanirima said, the girl cried when she urinated.

Mrs. Rahamtanirima borrowed money for the required medical exam. Nothing was left to buy the medicine the doctor had prescribed for Menja. Her file complete, the little girl traipsed in her frilly white dress to a courthouse as packed with accusers, accused and their supporters as a New York subway station at rush hour. She waited four hours, then sat down at a table before them all and, in a tiny voice, identified her uncle, seated across from her, as her assailant.

“We had to do it,” said her mother, who said that everyone in her village knew about the case and asked that her daughter’s name and picture be used. “Everybody should be aware that things like this should not happen to children.”

A Quest for Redress

Kenia’s parents, Antoine and Joazandry Moravelo, are equally passionate about the need for justice for their daughter. But after four fruitless years, they have all but given up hope. Though her photograph and name have appeared in local newspapers, they say, no one has been held accountable.

Kenia, the sixth of eight children, moved in with her aunt and uncle Lydia and Justin Betombo at the age of 8 after they promised to educate her. Sharing child care is common in Africa, and the Betombos, who lived 45 minutes away, had more than the Moravelos: a car and a two-room, tree-shaded house with sheet metal walls instead of the Moravelos’ thatched-roof reed hut.

But Kenia said the house was no haven. She said, “my uncle showed me his penis whenever he had a chance, and I always ran away.” Her aunt’s stock response, she said, was, “Don’t talk about that.”

One night in mid-2002, when her aunt was out, Kenia said, her uncle summoned her to his bed. “Because I refused, he came over to my bed,” she said. Afterward, she said, he told her, “If you talk about what happened, I will kill you.” She said she told her aunt anyway, and was instructed to keep quiet. The physical consequences of the attack, however, were hard to hide.

Kenia lost control of her bowels, had to quit school and was increasingly homebound. For six months or more, her only treatment was from a traditional healer who told her to boil herbs and wash with them. Finally, emaciated and weak, Kenia approached a neighbor. “She said, ‘I am sick; I am sick,’ and she was crying,” said the neighbor, Suzanne Mboty, who knew Kenia’s parents.

Hours after the neighbor reached his village, Mr. Moravelo retrieved Kenia. “She was so thin, so thin, I couldn’t believe it,” he said. Her mother said Kenia could not even sit down. “I opened her bag, and I saw all her underwear full of feces,” she said. “I said, ‘My God, what is this?’ ”

Kenia refused to say. But at the local health clinic, the nurse held up scissors and threatened to operate if Kenia did not talk.

That began nearly four years of medical procedures for Kenia, including a colostomy, two operations to close it, and repeated hospitalizations for wasting, incontinence and anorexia. Her mother said she sometimes refuses to eat because defecation is painful. Medical reports indicate that the muscle controlling defecation has been largely destroyed and her anal canal is heavily scarred.

The family is rent: Kenia’s parents had to sell their rice field and move to Diego-Suarez in the north for her treatment. Most of their other children remained behind, in the care of elder siblings. Kenia, now 13, is temporarily in Antananarivo, where a doctor is trying to treat her with a special diet.

A surgeon who recently examined her said a full recovery was unlikely. The uncertainty preys on Kenia, her mother said. “Sometimes she tells me, ‘My body is hurting. I have so many problems. I don’t go to school. I just feel this sickness all around me,’ ” she said.

The family’s legal efforts have met even less success. Mr. Moravelo lodged a complaint with the cash-short police, but the officers had no car; he hired a taxi so they could pick up Mr. Betombo for questioning. Frightened and sobbing, Kenia confronted her uncle at the chaotic station.

Justice Subverted

Mr. Betombo and his wife denied Kenia’s account. But ultimately — after the police beat him, Mr. Betombo said — he signed a confession, was arrested and carted off to the prosecutor’s office in nearby Antalaha.

Kenia’s father said that was the last he heard until a few days later, when friends told him that Justin Betombo was “free and happy” back in his village.

Mr. Betombo said he had convinced the prosecutor that his confession was false. Kenia’s parents say they were never summoned to contradict him.

“I took this girl in as my daughter,” Mr. Betombo said. “I really can’t understand why they say that I could have done such an awful thing to her. I think they were jealous of me and they wanted to ruin my life.”

Sambava’s police department again sent the file to the prosecutor’s office months later. But Sophie Ramahakaraha, the prosecutor in charge, now says that she has no record or memory of it. Real instances of child rape are rare, she said. “Very often the parents are poor and they use this procedure to get money,” she said.

But to Daul Randriamalaza, a Sambava police inspector, there is no question about who was the victim here.

“I don’t want to talk about corruption here, but that is what could have happened in this case,” he said as prisoners watched from the station’s tiny cell.

“I have children myself. How can I be happy about this?”