The tiny village of Meliandou, nestled in the Forest Region of southern Guinea, has begun to see flashes of the outside world. A Messi soccer jersey, three sizes too big, on a little boy. A down parka on an old man in the heavy heat, worn as a robe of distinction. You might even come across the occasional teenager on a cell phone, cupping the device from the sun as if lighting a cigarette in the wind. But mostly it is a place from the past—a rutted dirt path between thatch-roofed shacks, on a hillside sloping up toward the forest. It is home to just a few hundred people. Chickens and goats wander freely. Local shamans are the first responders when illness strikes.

In Meliandou, bushmeat has long been a common source of food. As elsewhere in West Africa, hunters wade into the forest and come back with whatever they can find. Once, not so long ago, what they found was a rich and varied bounty: monkeys, antelope, squirrels. That has changed; the whole eco-system has re-arranged itself. After civil wars broke out in Liberia and Sierra Leone, refugees poured over the borders, and the population grew, even as a power struggle in Guinea took an economic toll. People started looking to the rich resource all around them: trees. Trees were felled to make way for farms or burned down for charcoal. Endless truckloads of timber were shipped to construction companies. The forest suffered another trauma as mining interests—the Anglo-Australian Rio Tinto, the omnipresent Chinese—pushed aggressively to exploit the country’s natural resources (bauxite mostly). As the forests disappeared, so too did the buffer separating humans from animals—and from the pathogens that animals harbor.

Ordinary life in Meliandou came to an end on the day last December when the Ebola virus, which had last claimed a fatality thousands of miles away, arrived in the village, most likely in the body of a fruit bat—its natural non-human reservoir, according to a virtual consensus among scientists. Mining and clear-cutting had driven bats from their natural habitats and occasionally closer to people, like those of Meliandou. And fruit bats love palm and mango, which ripen in the village’s remaining trees. Bats also feed in colonies, which makes them tempting targets: a single shotgun blast can bring down 10.

Ebola is one of the deadliest viruses known to medical science, with no specific cure and mortality rates of up to 90 percent. The Ebola epidemic now raging in West Africa is the worst one in history. It has decimated Meliandou and moved far beyond. But the mystery today is not how the epidemic began—it is why a concerted effort by an army of international experts was unable to stop it. Part of the answer is the chameleon-like character the virus displays in this part of the world. An even larger part lies in the international response itself. It was rapid and comprehensive—exactly what you would hope. But there was an unexpected reaction that undermined everything the experts sought to achieve—and at the same time fooled many of them into thinking they had succeeded in their aims. Eventually they understood the truth. By then it was too late.

On the Move

As near as anyone can tell, the outbreak started when a few tiny rod-shaped particles—each merely an attack plan coded in ribonucleic acid and wrapped in a protein shell—found their way from a fruit bat into the body of a child not yet two years old. Perhaps, while the mother was preparing the day’s hunt, some of the bat’s blood was flung in the child’s direction. Perhaps, while the mother’s attention was elsewhere, the child touched the animal, then brought his hand to his mouth, the way babies do. Either way, a few strands of the Ebola virus attached themselves to cells in the child’s immune system and used the cells’ machinery to replicate. The boy developed a fever, then diarrhea and vomiting. His organs began to fail. He began to bleed internally and went into septic shock. In four days, he was dead.