The Kenyan government agreed to close Kitum Cave to tourists while the joint Kenya-U.S. expedition searched it for viruses. The head of the expedition was Dr. Peter Tukei of Kenya Medical Research Institute. Gene Johnson conceived the idea and gathered the equipment and found the money to pay for t. There were thirty-five team members, and most of them were Kenyans, including wildlife naturalists, scientists, doctors, and laborers. They brought along a large number of guinea pigs, traveling in boxes, and seventeen monkeys in cages, including baboons, Sykes’ monkeys, and African green monkeys. The monkeys and guinea pigs were sentinel animals, like canaries in a coal mine: they would be placed in cages inside and near Kitum Cave in the hope that some of them would break with Marburg virus. There are no instruments that can detect a virus. The best way to find a virus in the wild, at the present time, is to place a sentinel animal at the suspected location of the virus and hope the animal gets sick. Johnson figured that if any of his monkeys or guinea pigs crashed, he would be able to isolate the virus from the sick animals and would perhaps be able to discover how the animals had caught it.
1988 Spring
The Kitum Cave expedition set up headquarters in the Mount Elgon Lodge, a decayed resort dating from the nineteen twenties, when the English had ruled East Africa. The lodge had been built for sporting people and trout fishermen. It sat on a promontory overlooking the red-dirt road that wound up the mountain to Kitum Cave. It had once been surrounded by English gardens, which had partly collapsed into clay and African weeds. Indoors there were hardwood floors, waxed daily to perfect gleam. The lodge had turrets with round rooms and medieval doors, hand-carved from African olive wood, and the living room boasted an immense fireplace with a carved mantelpiece. The staff spoke very little English, but they were intent on maintaining English hospitality for the rare guest who might happen to show up. The Mount Elgon Lodge was a monument to the incomplete failure of the British Empire, which carried on automatically, like an uncontrollable tic, in the provincial backwaters of Africa long after it had died at the core. In the evenings, as the frost-tinged night came on, the staff built fires of Elgon olive logs in the fireplaces, and the food in the dining room was horrible, in the best English tradition. There was, however, a splendid bar. It was a quaint hideaway in a round chamber, stocked with shining rows of Tusker-beer bottles and French aperitifs and obscure African brandies. The men could sit at the bar and drink Tuskers or lean on the great mantel by the fire and tell stories after a hard day in the cave wearing a space suit. A sign on the wall by the concierge’s desk mentioned the delicate matter of money. It announced that since Mount Elgon Lodge’s suppliers had cut off all credit to the lodge, the lodge was unfortunately unable to extend any credit to its guests.
They moved the animals up the mountain in stages, to let them get used to the climate. When they got to the valley that leads to the cave, they cleared away some underbrush and put up blue tarpaulins. The cave itself was considered to be a Level 4 hot zone. The tarp closest to the cave covered a gray area, a place where the worlds met. The men took chemical showers under the gray-area tarp, to decon their space suits after a visit to the cave. Another tarp covered a Level 3 staging area, where the men changed in and out of their space suits. Another tarp covered a Level 4 necropsy area. Under that tarp, wearing space suits, they dissected any small animals that they had trapped, looking for signs of Marburg virus.
“We were going where no one had gone before,” Johnson said to me. “We brought the Biosafety Level 4 philosophy to the jungle.”
They wore orange Racal space suits inside the cave. A Racal suit is a portable, positive-pressure space suit with a battery-powered air supply. It is for use in fieldwork with extreme biohazards that are believed to be airborne. A Racal suit is also known as an orange suit because it is bright orange. It is lighter than a Chemturion, and unlike a Chemturion, it is fully portable, with a self-contained breathing apparatus. The main body of the suit (apart from helmet and the blowers) is disposable, so that you can burn it after using it once or twice.
Wearing their Racal space units, they laid out a trail that wound into Kitum Cave, marking the trail with avalanche poles so that people would not get lost. Along the trail, they placed cages holding the monkeys and guinea pigs. They surrounded the cages with electrified wire, powered by a battery, to discourage leopards from trying to eat the monkeys. They placed some of the monkeys directly underneath bat colonies in the roof of the cave, hoping that something would drop on a monkey that would cause the animal to break with Marburg.
They collected somewhere between thirty thousand and seventy thousand biting insects inside the cave—the cave is full of bugs. “We put stickum paper over cracks in the cave, to catch crawling bugs,” Johnson said to me. “We hung light traps inside the cave to collect flying insects. The light traps were battery powered. You know how to collect ticks? They come out of the ground when they smell carbon dioxide from your breath. They smell it and come up and bite your ass. So we brought these huge tanks of carbon dioxide, and we used it to attract ticks. We trapped all the rodents that went into the cave. We used Havahart traps. Way at the back of the cave, by a pool of water, we found sand flies. These are biting flies. We saw leopard tracks all over the place, and Cape-buffalo tracks. We didn’t take any food samples from large animals, nothing from leopards or buffalo. Nothing from the antelopes.”
“Could Marburg live in large African cats?” I asked. “Could it be a leopard virus?”
“Maybe. We just didn’t have permits to trap leopards. We did collect genet cats, and it wasn’t there.”
“Could it live in elephants?”
“Did you ever try to draw blood from a wild elephant? We didn’t.”
The Kenyan naturalists trapped and netted hundreds of birds, rodents, hyaxes, and bats. In the hot necropsy zone, under the tarp, they sacrificed the animals and dissected them while wearing Racal suits, taking samples of blood and tissue, which they froze in jars of liquid nitrogen. Some local people—they were Elgon Masai—had lived inside some of the caves on Mount Elgon and had kept their cattle in the caves. The Kenyan doctors drew blood from their cattle. None of the local people or the cattle tested positive for Marburg antibodies—if they had tested positive, it would have shown that they had been exposed to Marburg. Despite the fact that nobody showed signs of having been infected, the Elgon Masai could tell stories of how a family member, a child or a young wife, had died bleeding in someone’s arms. They had seen family members crash and bleed out, but whether their illnesses were caused by Marburg or some other virus—who could tell? Perhaps the local Masa people knew the Marburg agent in their own way. If so, they had never given it a name.
None of the sentinel monkeys became sick. They remained healthy and bored, having sat in their cages in the cave for weeks. The experiment required that they be sacrificed at the end of the time so that the researchers could take tissue samples and observe their bodies for any signs of infection. At this point, the hard part of primate research began to torment Gene Johnson. He could not being himself to euthanize the monkeys. He couldn’t stand the idea of killing them and couldn’t go into the cave to finish the job. He waited outside in the forest while another member of the team put on a space suit and went inside and gave the monkeys massive shots of sedative, which put them to sleep forever. “I don’t like killing animals,” he said to me. “That was a major issue for me. After you’ve fed ‘em bananas. That was terrible. It sucked.” He put on his orange Racal space suit and opened up the monkeys under necropsy tent, feeling frustrated and sad, especially when all the monkeys turned out to be healthy.