Scientists Hunt Deadly Ebola Virus in African Rain Forest

Dawn has barely broken when Jonas Tahou enters the forest, trousers stuffed into knee-high rubber boots that sink in the mud as he marches silently through the trees and tangled vines.

Somewhere in this sweltering jungle, in the deep green thicket that blocks the sun and swallows up Tahou’s slender form, lives a killer rarely seen but always present, one that prowled the forest perhaps thousands of years before emerging 20 years ago to earn the name Ebola.

Two decades after the first known outbreak of the virus and 18 months after its deadly resurgence in the Zairian city of Kikwit, a fledgling international effort is underway in this remote rain forest along the Liberian border to track Ebola’s source before it strikes again.

As he moves deeper into the trees, the quiet broken only by the squish of his boots and the cries of the forest, Tahou checks dozens of traps placed on the ground to capture rodents. If he is lucky, there will be a shrew or perhaps some mice or rats to take back to camp, euthanize and slice open to test their tissues for Ebola.

There are no high-tech labs with filtered air pumped in, no link with the Pentagon to report new discoveries, no helicopters to rush deadly samples to Europe or the United States. The traps Tahou checks are plastic buckets shoved into the mud; the tiny mammals are gassed in old sour cream cups; lab liquids are stored in wine bottles. There’s a jeep that works sometimes, a telephone two hours’ drive away, and a steamy autopsy room lit by one bare bulb when the generator is cranked up.

“Outbreak” it isn’t. But to the disparate group of men and women drawn together here--agile forest dwellers like Tahou, a U.S. Army major and ex-rodeo rider, an Australian veterinarian who nurses her infant daughter between bat autopsies--it’s the best chance yet to crack the riddle of one of the deadliest viruses known.

“The conditions are crude and sometimes it’s difficult, but we want to get past this enigma of Ebola,” said Pierre Formenty, a French doctor who heads the World Health Organization project. “It’s a struggle for the world--we’re all in the same house. The diseases emerging today in Cote d’Ivoire may be the diseases emerging tomorrow in China or Colombia.”

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The fear of new or reemerging diseases has been underscored by the worldwide AIDS epidemic and by resurgent infections of tuberculosis, yellow fever and malaria that are increasingly resistant to drugs. Deaths from infectious diseases increased 56% from 1980 to 1992, according to the U.S. Centers for Disease Control and Prevention.

Perhaps no disease conjures up such terrifying images as Ebola, named after the Zairian river flowing through the region where it first appeared in 1976. Ebola kills up to 80% of its victims, causing them to bleed to death internally.

It usually strikes in remote regions without modern medical facilities. In many cases, terror takes over--doctors are afraid to treat the ill for fear of contracting the gruesome disease, so patients remain among the general population, spreading the virus. In Kikwit, 245 people died before the outbreak was stopped. At least 13 died of Ebola in Gabon in February, and a new outbreak in October killed at least 17 there. Two more cases recently showed up in South Africa--a doctor and a nurse.

There’s no guarantee the Tai project, with a budget of $250,000 for two years, will succeed in finding the plant, animal or insect where the virus thrives when it’s not on its deadly rampage through humans. But there are signs the hunters are on the right track.

In June, two months after the project got underway, tissue from a Red Colobus monkey found dead in the forest tested positive for Ebola. The henna-colored apes are a major food source for chimpanzees, which in the past have also tested positive for Ebola.

That’s a clue that Ebola might originate in the Red Colobus, although Formenty says it probably isn’t that simple. With the monkeys living in large social groups with frequent physical contact, the virus probably would afflict more than just one at a time. One theory is the monkeys catch the virus from bats sharing the trees in which they live, or from one of the ground rodents that scamper up these trees and leave droppings on the leaves eaten by the Red Colobus.

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So the Ebola hunters have turned the closely guarded Tai forest--a protected area off-limits to all but researchers--into a rodent’s worst nightmare.

It is an obstacle course of traps designed to snare everything from the tiniest shrews to the widest-winged bats. Mousetraps and buckets are sprinkled across the forest floor. Nets to snag bats and birds hang from narrow wooden planks that wobble 100 feet above the ground.

Each morning, Ivorian assistants such as Tahou, who has spent his life around this forest, check the day’s catch. In the makeshift lab, Susanne Anderson, the Australian vet, methodically measures and weighs each animal before taking blood or tissue samples.

Anderson arrived in September with her chimpanzee researcher husband, Dean, their 3 1/2-year-old son and 5-month-old daughter. They live, along with a fist-sized furry spider, in a simple concrete dwelling lit by candles stuffed into Chianti bottles. Evenings are spent in a thatched-roof communal gazebo that serves as a dining room and meeting spot.

The atmosphere is relaxed, far from the frantic mood in Kikwit or the panic portrayed in “Outbreak,” the Hollywood blockbuster about an Ebola epidemic enveloping a California town.

“My friends think I’m crazy,” Anderson says with a laugh, but she doesn’t worry about passing Ebola to her children.

The conditions are primitive, but safety standards in the lab are strict. She and Formenty wear surgical gloves, cloaks and face masks, along with plastic visors that fog up as the temperature climbs in the room. Her concentration is palpable as she inserts needles into bat wings and snips open the bellies of shrews.

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A Swiss scientist contracted Ebola here in 1994, apparently during a chimpanzee autopsy performed while she wore gardening gloves. The gloves apparently allowed some of the animal’s infected blood to penetrate her skin, a classic form of transmitting the virus, which is passed through bodily fluids.

She recovered, and the case prompted scientific interest in the Tai forest as an Ebola source. Ebola appears to have a cycle here, emerging late in the year after the rainy season. The Swiss woman fell ill in November 1994; one year later, a Liberian man living just across the border contracted Ebola. The Tai team hopes its project will coincide with another outbreak.

“With Ebola, you don’t like to see it emerge from wherever it is, but that’s the only way you can study it. By being in the Tai forest, where there’s already a history of Ebola problems, we’re just hoping to be here at the right time,” said U.S. Army Maj. Neal Woollen, a veterinarian from the Army’s Medical Research Institute of Infectious Diseases who also worked on the Kikwit outbreak.

It’s not only the apparent pattern that makes Tai an ideal research spot. The forest has been a focus of primate studies for more than a decade, so its monkey and chimpanzee groups are well known to other scientists who have been tracking them for years. If one dies mysteriously, the animal researchers will alert the Ebola hunters to test it.

The Ivorian government welcomes the research, a rarity in Africa, where other governments have been loathe to admit their countries could be the source of a hideous disease.

The government of Gabon refused to acknowledge the presence of Ebola during a 1994 outbreak there and officially classified the incident as a yellow fever outbreak. When Ebola broke out again this year in Gabon, the government was similarly resistant and battled with Formenty to keep casualty numbers artificially low.

Even with Ivory Coast’s cooperation, there are problems. There is no laboratory in Abidjan to test for Ebola, so samples must be sent to Europe or the United States, packaged as hazardous material and transported on special cargo flights that are often booked up a month in advance.

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Science can’t always wait. When medical experts suspected Ebola was loose in Kikwit, one doctor sneaked a blood sample on board a commercial flight and smuggled it out of Zaire. The blood was tested at the Centers for Disease Control and provided confirmation of Ebola in Kikwit.

The biggest obstacle, though, remains spotting the virus as soon as it emerges and blocking its progress to other animals or humans.

“The unfortunate side of that is if Ebola causes another problem, some more chimps or monkeys or something else in the forest is going to die,” Woollen said. “It’s kind of a two-edged thing. . . . On one hand, we’re hoping the virus will cause a problem from a scientific aspect. From a humane aspect, in terms of caring for the creatures of the forest, you hope it never resurfaces.”