Kikwit, Zaire -- There are four photographs in all, carefully recording a family's loss. They show Gaspard Menga's funeral, with his open wooden coffin, wrapped in colorful contact paper, flanked by more than a dozen grieving relatives.

Bebe Menga is there, of course. She clutches the youngest of her six children, 2-year-old Michael Jackson Menga, while weeping over her husband's face. Philemond Nseke, the uncle who years ago had been so enraged at Gaspard for leaving the Catholic faith that he changed his family name, is standing stiffly to the side. Philemond's wife, Marie-Jose, cradles Gaspard's head in her hands and cries out in grief.

As is the custom among the KiCongo people of Zaire, those closest to the coffin have their hands on Gaspard's body -- a final gesture of goodbye to a beloved and hardworking father, husband, brother and son.

Last week, outside his thatched roof home in Kikwit, Pierre Menga, Gaspard's 26-year-old brother, offered his help and his photos to one of the foreign doctors who had come to seek the origins of the deadly Ebola outbreak in Zaire. Under a sun so strong it bleached the faces in the photos into ghostliness, Pierre pointed with a ballpoint pen to one person after another.

"Lui: decede," he said speaking French. ["Him: deceased."] "Lui: decede. Elle: decedee. Lui . . ."

By the time he was done, he had jabbed at about half the mourners in the picture.

The Menga family photos are more than just reminders of one family's loss. They may show the moment when a single sorrow turned into an outbreak that would grab the attention of public health officials worldwide and kill more than 120 people before apparently coming under control last week.

Gaspard Menga probably was the first human infected in the Kikwit outbreak, say the scientists on the international team that has come to contain and study the outbreak. And his funeral rites, their finale so carefully recorded on film, may have helped pass it to the general population.

Four major chains of transmission have been found so far in the Zairean epidemic: the Menga chain was the earliest, the World Health Organization's Dr. Guenael Rodier said last week.

Of 23 members of the extended Menga-Nseke family, 13 perished of Ebola between Jan. 6 and March 9. Four of them died in Kikwit General Hospital. That means the deadly virus probably lurked in the hospital for more than two months -- perhaps mistaken for shigella, a common bacterial disease -- before erupting in mid-April when surgery on an infected laboratory technician named Kimfumu spread Ebola to a dozen doctors and nurses.

If Menga was first, he probably got the virus from whatever animal normally carries Ebola. And that means the 19-year quest for the virus^ reservoir -- its animal home between human outbreaks -- soon may end.

For somewhere in the small plot of corn and manioc that the 35-year-old farmer cultivated in Kikwit, or in the nearby forest where he gathered wood to make charcoal fuel, may lurk the beast that carries Ebola.

But even if it turns out that Menga got Ebola from another human being -- still possible, doctors say -- understanding what happened to the Menga family could shed important light on a virus that has remained rare and mysterious since it first erupted in 1976 in Zaire. The virus can spread readily through contact with infected blood or bodily fluids. But can it spread other ways? How many, like Pierre Menga, are exposed to the virus but escape illness -- and why? How does the virus change as it passes from person to person? The answers to questions like these might help prevent or contain outbreaks in the future.

The doctors were not the only ones who wanted to know. Pierre and his father, Innocent, a frail man who looks older than his 65 years, were eager, desperate, to share their story with the researchers and the world in hopes of learning why such grand tragedy has befallen their family.

"This has been most difficult," Innocent murmured.

A week ago, Pierre Menga eagerly agreed to guide medical investigators to the villages where Menga family members had lived and died, in search of further clues. The search party would include Belgian physician Robert Colebunders and Jean Bosco Katshunga, a local accounting student hired to assist the doctors, accompanied by this reporter.

The journey would span two days, covering about 240 miles of rough dirt road. It would be typical of the Kikwit investigation, using the time-honored techniques of epidemiology: detailed questioning, close examination and the search for overlapping clues that might connect one case to another. In each of a dozen villages, the questioning would begin with the search for active cases of Ebola, followed by detective work aimed at determining where the Menga family clan went after Gaspard's funeral and whom, if anyone, they may have infected.

The basics were simple:

Gaspard Menga died Jan. 13 in Kikwit General Hospital. For a week, he struggled against some unknown enemy, suffering a soaring fever, headaches, horrible stomach pains, uncontrollable hiccups and massive bleeding -- bloody vomit, bloody diarrhea, bloody nose, blood from his ears . . .

Bebe, Philemond and Bibolo all died within weeks of preparing Gaspard's body for burial -- the preparation being a traditional procedure that involved washing the corpse. Philemond's 19-year-old daughter Veronique also died, having helped care for her ailing father.

In each case, the family was told the killer was shigella, which also causes bloody diarrhea and kills thousands of Africans each year. When the Ebola epidemic hit the hospital two months later, no one made the connection to the Mengas, not even the doctor who had treated four of the family members and still sees Innocent, the father, for his tuberculosis.

The link might have gone hidden far longer, or forever, if not for Katshunga, the accounting student.

Katshunga happens to live just up the hill from Pierre Menga. In January and February, he had heard the wailing of the Menga family funerals again and again. Later, when Ebola struck, he was one of about 40 local college students hired and trained to assist the international medical team in ferreting out cases. Then, about three weeks ago, he walked down the hill, asked Pierre about all the family illnesses and recognized the symptoms of Ebola.

Now he and Colebunders would try to determine how far the Menga chain of transmission had spread.

For Colebunders, the journey would prove an error. Two weeks earlier, he had received word of the Ebola outbreak from a colleague at the Institute of Tropical Medicine in Antwerp. The 46-year-old physician, who studied AIDS in Africa, was preparing to attend the funeral that day of a medical school colleague, and was still grieving the death of his father-in-law three months earlier.

"But I said, `Oh! Ebola! I'm interested. I want to help. I knew there would be many people interested in Ebola, and there would be a rush, a sort of competition, to get there [Kikwit] as soon as possible," Colebunders said.

As the surveillance team's mud-encased white Land Cruiser bumped its way north out of Kikwit on May 22, Colebunders talked incessantly, oblivious to the extraordinary changing scenery of grassy knolls, jungle, plains and small wattle-and-thatch villages.

"I am not feeling well," Colebunders announced at last, as he fought back tears and what he described as a deep wave of almost paralyzing depression.

Since his May 14 arrival in Kikwit, Colebunders had been in charge of the hospital's emergency room. As the hemorrhaging bodies poured in, Colebunders fought back his personal fears and, dressed in protective mask, gloves, goggles and gown, examined the patients.

His staff of Zairean doctors and nurses had gone unpaid since 1991, when Zaire's government fell apart amid a military uprising. Virtually all the basics of medicine -- sterile syringes and instruments, washable hospital beds, functioning latrines, clean water and electricity -- were missing from Kikwit General Hospital.

"Six of the ER nurses died of Ebola," Colebunders said gazing out the window at nothing in particular. "I have begged the [WHO] laboratory for something to protect me. But even now I am not protected . . .," he added, his voice trailing off.

"I do my best. I do my best. But I am not well," Colebunders mumbed, referring to his emotional condition.

For the rest of the journey, much of the investigation fell to Katshunga and this reporter, with assistance from Pierre.

The first stop was Kimputu-Nseke, an orderly collection of wattle homes and small shops clustered loosely around the road from Kikwit. A cool breeze blows from the south, carrying tantalizing botanical odors from the nearby tropical woods. A group of pretty women, dressed in brightly colored kanga wrap-around skirts, clustered around the handsome Pierre, quietly exchanging news and gossip.

After Bebe's funeral, Romainie Mawita, age 35, returned to this quiet village, the women said, where she had lived for several years. Bebe Menga was her sister, and Mawita had cared for her dying sibling.

Two weeks after Bebe's funeral, Mawita, four months pregnant, miscarried. The stillborn fetus was, according to the villagers, "abnormal," though they offered no details. By Feb. 19, Mawita was horribly ill, another victim of Ebola. She died in one of the wattle huts of Kimputu-Nseke on Feb. 20.

The next day Mawita's year-old daughter, Jolie, also fell ill, dying of Ebola on Feb. 23. Mawita's younger sister, Elisa Ando, came to Kimputu-Nseke, preparing Mawita and Jolie's bodies for burial. Ando did not have Ebola even six weeks after she had returned to her home of Ndobo, and no other residents of the village have come down with the disease.

The search continued from Kimputu-Nseke through about a dozen smaller villages, where none of the elders recalled any illnesses that sounded like Ebola.

As a moonless night descended, the weary team settled into the abandoned former home of an American Baptist missionary, at the Nkara Mission. By the light of kerosene lamps the team compared notes on the day's findings, ate canned sardines and bread, and planned the following day's work. Exhausted, they quickly fell to sleep under mosquito nets, in rooms lit only by the pinpoint glows of dancing fireflies.

In the morning 21-year-old Asinki Maleki, a Mission School student, introduced herself as Romainie Mawita's sister, Pierre's cousin. She urged the group to push on another 60 kilometers to Ndobo, where she had helped care for other dying members of the Menga-Nseke family. Well past the incubation time, Maleki was free of Ebola.

Ndobo proved to be a chaotic horror of a ramshackle village. The elderly Chief Santu wielded little control over the scores of ragged children who swarmed through the village shouting and begging for money. Instead, village men occasionally hit and herded the children with the same sticks they use to drive livestock. By an informal head count, children under 12 outnumbered adults 15 to 1.

It was here that Gaspard and Bebe's six orphaned children were sent, to be cared for by their 45-year-old grandmother, Jeannette Bekene. The six youngsters merged into a household that already contained eight other children and at least three other adults, all crowded into a one-room rectangular hut about 10-feet by 12-feet in size.

Shortly after their arrival, 2-year-old Michael Jackson Menga - named after Bebe's favorite musician -- fell ill, dying Feb. 11 of Ebola. His 7-year-old brother, Judo, died five days later of the disease, village sub-chief Mbelo said.

Three weeks later their grandmother, Bekene, died of the disease. Then her brother, Hogui Pisambo, who had tended her in her illness and had helped prepare the little boys^ bodies, died of Ebola March 9.

And, remarkably, the Ndobo chain of transmission died with him. None of Michael Jackson and Judo's siblings -- Asinta, Gizelle, Bilolo and Lenza -- took ill, despite having touched the ailing family members. Not one member of the Bekene household, except Jeannette, got Ebola, though they were all certainly exposed to the virus. And a neighboring family, the Mbelos, remained healthy despite having prepared Pisambo and Bekene's bodies for burial.

Now, along the footpath that Ndobo residents travel daily to reach their corn and manioc fields lay four fresh graves, tended to by four small children, the orphaned offspring of Gaspard and Bebe Menga.

The children, now cared for by the Mbelo family, were wide-eyed and silent. They seemed overwhelmed, as much by the screaming swirl of youngsters around them as by the tragedy that had transformed their lives.

From Ndobo, three hours^ backbreaking drive brought the team to Mukolo, a village whose background music was the peaceful thud of girls pounding manioc into flour with wooden pestles taller than they were. Here Philemond Nseke's widow, Marie-Jose, arrived on Feb. 5.

With the grieving 31-year-old was her sister, Sidonie Ando, 21. By Feb. 15 both women were dead of Ebola. As in Kimputu-Nseke and Ndobo, transmission never spread beyond the family.

Back in Kikwit, Pierre expressed relief that his family's tragedy hadn't sparked epidemics in the far-flung villages. And the scientists had a few more clues to add to the Ebola puzzle.

First of all, the Mengas^ experience, like the other chains of transmission, seem to show that Ebola initially simmered in Kikwit, spreading within families for two to three months. It exploded into an epidemic in mid-April in the hospital. In all chains of transmission the virus seems to have hit hardest in the first rounds of spread, waning in transmissibility and virulence over time, eventually burning itself out.

For example, early in the epidemic a nurse at the Mosango Mission Hospital became infected tending a patient who had fled Kikwit, a 90-minute drive away. The nurse died after particularly acute hemorrhaging. The terrified staff disinfected and scrubbed the room, burned the bed linens and sealed the chamber for two weeks. Fifteen days after the nurse died, a young woman with an unrelated problem was placed in the room, Mosango physicians said. She contracted Ebola, and died. Her only contact with the virus, scientists say, was the mattress upon which she lay.

But the nurses who cared for her never contracted the disease.

The pattern is similar to that seen in the three previous Ebola outbreaks, in Zaire and Sudan in the 1970s, when the virus struck with initial ferocity but faded within months.

To biologist Robert Swanepoel, who is leading efforts in Kikwit to track down the natural source of Ebola, the burnout implies that Ebola rarely infects human beings. Thus, when it does, it must reduce its virulence to adapt to the human host. If a virus is too deadly, he explains, it has less chance to reproduce itself and spread.

"After all," said Swanepoel, of the National Institute of Virology in Johannesburg, "it's not in a virus's interest to kill off all its hosts."

A new team of scientists is now arriving in Kikwit, replacing those who have helped stop the epidemic. They will retrace the steps of the disease detectives. They will draw blood from all the healthy individuals, like Pierre Menga, who touched the dead and cared for the ailing. They may even learn enough to tell Pierre and Innocent Menga why their family was the first and most grievously struck in Zaire's 1995 Ebola epidemic.