We planned to calculate predictive values—positive and negative—for our test. The sensitivity and specificity of diagnostic tests are often reported, and it is easy to calculate them. They are readily understood. But more useful information is presented when predictive values of tests are given. That sounds simple, but predictive values of tests vary with the prevalence of the disease in the population to which the test is applied. We would know how many of the soldiers we tested had tuberculosis because we would obtain X-ray examinations on all of them. Thus, we could calculate predictive values. How widely the results in soldiers could be applied to the general population of Bolivia was a matter that we could only speculate about.
The second group of studies we planned were more complex and less certain of outcome. They involved the study of tuberculosis in relation to altitude. Tuberculosis was common among people living on Bolivia’s Altiplano and on the slopes of the Andes Mountains at altitudes of 14,000 to 16,000 feet. It was not common in the lowland eastern regions of the country. In addition to Bolivian Ministry of Health reports, in which we had limited confidence, there were data collected from 1967 to 1971 in association with an American Peace Corps tuberculosis control program in the Yungas. Elevations in the Yungas ranged from 4,000 to 8,000 feet. We were particularly interested in the town of Suapi at an elevation of about 5,000 feet. The Peace Corps data revealed less tuberculosis there than elsewhere in the Yungas, and TB skin testing results suggested to us that residents there might have some degree of immunity resulting from exposure to harmless environmental cousins of the tubercle bacillus, probably in the local soil.
We wanted to collect blood from persons living in Suapi and Coroico, a nearby town at about the same elevation with many cases of tuberculosis among its inhabitants. We would then harvest the immune cells from the blood we drew and stimulate them with antigens that Jennifer and I had harvested from tubercle bacilli and some of its soil-dwelling cousins. That, of course, meant getting the freshly drawn blood back to INLASA within a few hours. A challenge, but doable, Gonzalo and I thought. We would need to know the tuberculin skin test reactivity of the persons from whom we drew blood, and we would be looking for individuals ill with tuberculosis.
We would not only study cells from Coroico and Suapi. We would also study cells from individuals in La Paz, including the soldiers whom we screened for tuberculosis. In this manner—comparing Yungas results with soldiers in La Paz—we might get some clues about the effect of altitude with its low blood oxygen on cellular responses to tuberculosis antigens.
We expected to get all of this work under way within a week or two. That would prove to be somewhat optimistic.
10
Leaving the Torax, we made our way up Avenida Savedra. In La Paz, I had learned, directions are neither east or west nor left or right. In this canyon-side city they are up or down. We were headed up and across the mountains to the Yungas. Gonzalo was driving his van.
We passed the large stadium. Paceños (residents of La Paz) were proud of their futbol team. Helped by the need of competing teams from lower altitudes to adjust to the altitude and by the enhanced oxygen-carrying capacity of their own blood, futbolistas from La Paz did well in international competitions both at home in La Paz and elsewhere. Then we drove farther up through the district named Miraflores. Translated into English, Miraflores means something like “see the flowers.” A vain hope in La Paz. No flowers and few trees grow at the altitude of La Paz. Sycamore trees lined the road in Miraflores, poled, however, as in Paris, where they are known as plane trees. They tolerate the altitude of La Paz.
Leaving the city, the road wound up in hairpin turns, following a tumbling river. This river would join that which flowed through La Paz—mostly under it, at least in the central city. Ultimately the water that cascaded beside us would make its way into the Amazon. As we climbed, trees became sparse, and sycamores gave way to eucalypti. Those trees, originally imported from Australia, thrived in the high, dry, Bolivian climate where others would not grow. Increasing amounts of snow bordered the road.
After an hour we reached the cumbre (summit). Gonzalo pulled his van off the road and stopped. A sign told us we were at 4,650 meters, about 15,260 feet, above sea level. We got out of the vehicle. The highest I had ever been with my feet on the ground. Gonzalo commented that another mountain road leaving La Paz climbed to about 17,000 feet, where the French had built a cosmic ray observation station. A Bolivian ski club had installed a primitive ski tow there at the edge of a glacier.
Overhead two Andean condors with their distinctive white heads soared, riding the mountain updrafts. These largest of raptors are found only high in the mountains of South America. Not far from us a herd of llamas and alpacas grazed. I knew about these camelids, the only large mammals indigenous to South America. Bolivians raise llamas as beasts of burden, although the loads they can carry are modest in size and weight. Bolivians also eat llama meat, although goat is preferred. Alpacas are never eaten; they are too valuable to be butchered.
The fleece of a llama is coarse with a long staple. Tough yarn. Good for rugs, and bolsas (sacks) but not for clothing. Alpacas, on the other hand, have soft fleece, yielding yarn much prized for hand-knit chompas (sweaters) and woven ponchos, and aguayos. An aguayo is a carrying cloth essential to every Andean woman. Square, about a yard wide, it is hand-woven in two parts that are then sewn together. A wide longitudinal area in each half, the pampa (field), is of a color specific to the region where its owner lives. Babies, groceries, items of value are folded into the aguayo, which is then carried on the woman’s back, high, next to her shoulders, with corners coming together in front and held tenaciously in her hands.
Back in Gonzalo’s van we were ready to make our way down into the Yungas. We drove back onto the road and began our descent on the Yungas road. It has been called “the world’s most dangerous road.” Hugging cliff sides, it was anything but an easy drive. Crosses, sometimes decorated with flowers, dotted the roadside at sharp drop-offs. Occasionally the remains of an irretrievable truck lay in the riverbed beneath the cross-marked roadside. As we rounded a curve where there was a steep drop-off we saw what appeared to be a family recovering possessions from a truck that had gone off the road and rested on its side in a stream below. Derrumbes (landslides) are frequent, and bulldozers work continuously at sites prone to these events.
In the 1930s Bolivia and neighboring Paraguay fought a war over a border region known as the Chaco. Dry and barren desert, the Chaco was thought to be rich in oil. A potential prize in an area the borders of which had never been clearly established, a potential prize claimed by both nations. It was a futile war that dragged on for about three years, ultimately ending in Paraguayan victory and ownership of about two-thirds of the disputed land. There was no oil in the Chaco, however. Many captives were taken on both sides. The Bolivians put their prisoners to work at road building, and we were about to descend the serpentine result of the labor of those men.
The name, Yungas, comes from the Aymara word, yunka, variously said to mean warm place or place of trees. And warm and pleasant the Yungas is, with many trees. Lush vegetation, much of it appearing as though it had been created by Dr. Seuss. Flowers everywhere: hibiscus, bougainvillea, gardenias, and poinsettia bushes tall enough to stand under. The steep hillsides are terraced. Some fruit—avocados, papayas, oranges, and bananas—and coffee grow in the Yungas, but the major crop, the one that fills the carefully built and tended terraces, is coca. Coca leaves, looking somewhat like bay leaves, are picked from the low bushes three times a year. The leaves are dried on flagstone terraces. Crude cocaine is extracted with kerosene, which is then allowed to evaporate. The resulting proto-cocaine then makes its way north to be further refined before reaching Los Estados (the States).
The road before us swept across the face of a large cirque. Beneath us and ahead of us clouds shrouded much of the valley. Our destinations were Coroico and Suapi. First, however, we had to deal with Unduavi. The Yu
ngas road divides at Unduavi into north and south branches. We would go north.
It was raining as we entered Unduavi; as we made repeated trips into the Yungas, we would come to believe that it never stopped raining in Unduavi. Moisture-laden prevailing winds from the southeast cross the continent and drop their water as they rise up the Andean slopes. In contrast to the dry desert western slopes of the Andes, the eastern mountain regions receive abundant rain. Trucks were parked along the roadside stretching back up the road. There was a toll station at Unduavi, and also a place to buy gasoline and diesel oil. It was primitive by North American gas station standards or those of gas stations in La Paz. One worked a handle to move gasoline into a glass chamber at the top of the pump. Compressing the handle on the gasoline pump’s hose allowed the fuel to run down into the vehicle’s gas tank. Thus we filled the tank of Gonzalo’s van.
We entered the roadside building, and Gonzalo entered our names, vehicle make, and plate number, and our destination into a log book. “Do you suppose anyone will ever look at that entry?” I asked.
“No. But it’s part of Bolivia’s bureaucracy. Actually, someone will probably copy it out again and post it somewhere in La Paz. And no one will look at it there, either.”
Driving on, we hugged the cliff side. Suddenly, rounding a curve, we found ourselves face-to-face, radiator grill-to-radiator grill, with an upward-bound truck. The truck was loaded with many bolsas—sacks of produce, we supposed. People sat on top of the truck’s load. Cautiously, Gonzalo backed up until the road was wide enough for the truck to pass us. “Gonzalo,” I said, “your van needs a loud air horn to warn approaching trucks. I’ll pay for one for you.”
“Yes,” he replied, not continuing the conversation as he concentrated on the road.
We drove into Coroico. Not a large community, but a market town and a commercial center of sorts for the surrounding area. In Coroico we checked into the Hotel Prefectoral, Coroico’s only hotel. We had our choice of rooms; there were no other guests.
Leaving Gonzalo’s van at the hotel, we set off on foot to visit the local hospital. Bolivia had built small hospitals in five Yungas towns. Graduating medical students were required to spend their initial year after commencement at a rural clinic—an año de provincias (year in the provinces)—perhaps at one of those in the Yungas. It was hoped that some of these graduates would find medical practice in underserved communities attractive. In fact, the lack of supplies, support, and consultation opportunities and the rural living situations for former city-dwellers had the opposite effect. Few of them stayed beyond the obligatory year. None were present in Coroico at the time of our visit.
The Coroico hospital included a clinic area, a ward with four beds, and a small laboratory. It was staffed by two missionaries, Canadian nurses, who brought their skills and a small measure of Baptist evangelicism to Coroico. They provided the medical care available to the residents of Coroico. The laboratory was equipped to do urinalyses, sputum smears for tuberculosis, and assessment of anemia by a long-outmoded technique based on the color of blood in a finger stick. The nurses were interested in our proposed work, and we felt we could count on their support in this small community where news and opinions circulated widely at every morning market.
We next went in search of Martino Lopez, who we had learned was the alcalde (mayor). We found him in a bar and treated him to another cerveza (beer), also getting beer for ourselves. We explained that we would make many trips to Coroico and Suapi, depending on how our work went. Each time we would want to draw one syringe-full sample of blood from an individual with tuberculosis—the Canadian nurses had offered to help identify those persons—and also from one healthy individual of about the same age. We would pay our subjects thirty bolivianos for each blood drawing. Mayor Lopez offered his support—and ordered another round of beer for the three of us. In fact, he would be pleased if we would take his blood for estas investigaciónes muy importantes (these very important studies). I paid the bar bill for the three of us, and Gonzalo and I headed back to the hotel for dinner.
The menu at the dining room in the Hotel Prefectoral offered two entrées: lomo montado and Milanesa. Gonzalo chose the lomo (loin, steak). I chose the Milanesa, something Italian, I presumed. Gonzalo’s lomo arrived with a fried egg on top of it—the montado part of it, I supposed. My Milanesa was, I assumed, intended to be a cutlet in an Italian style. At least it appeared to have spaghetti sauce on it. The two pieces of meat looked identical. Goat, perhaps. We had seen many goats as we drove into town. No cattle. Rice and fried plantain banana slices accompanied the meal. The postre (dessert) was a flan that was delicious. The best part of the meal.
A beautiful morning dawned in Coroico. We turned Gonzalo’s van onto the road to Suapi, a road better suited to mules than to automotive vehicles. After fording three small rivers we mounted a ridge and saw Suapi nestled in the valley beyond us. We drove down and into the central plaza. Suapi was too small a town to have an alcalde, but Alcalde Lopez in Coroico had given us the name of a man who he assured us was the de facto leader of the town. A crowd gathered, and Gonzalo’s van was inspected and much admired despite its obvious age. When we identified ourselves as médicos, a young woman was brought to us. She opened her shirt to reveal a red and angry left breast, clearly infected. A cellulitis, Gonzalo and I agreed. “Is there a farmacia (pharmacy) in Suapi?” Gonzalo asked.
“Si, Señor,” said a man who was obviously the town leader Lopez had identified.
We led the woman to the pharmacy. Gonzalo purchased a syringe-full of penicillin, which he injected into her shoulder. I then purchased a ten-day supply of oral penicillin. “Take these tablets twice a day until they are all gone,” directed Gonzalo. “Even after your breast is better, keep taking them.”
“Gracias, muchisimas gracias.” The woman took the penicillin and smiled.
With such a propitious entry, we found our proposal to draw blood in Suapi received graciously. The proffered thirty boliviano payment would be welcome in this small village.
We headed back to La Paz, planning to time our return driving time, back to Coroico and then over the cumbre to La Paz. Approximately fifty miles. Five hours, we estimated, but it would take longer on this trip. As we traversed the large cirque above Unduavi, Gonzalo’s van sputtered, then came to a stop. “Shit,” Gonzalo said. “We’re out of gas!”
“We passed a ‘Se Vende Gasolina’ sign back a bit,” I said.
“Too far to walk, I think,” Gonzalo replied. “Get out and give me a shove. If I can roll back to the last curve, we can turn around and coast downhill, hopefully as far as the gas place you saw.”
We managed the turn and, with an occasional further shove by me, we rolled down through three switchbacks to the small building where I had seen gasoline for sale. In response to our query, a boy whom I judged to be about ten or twelve years old indicated that he had gasoline that he could sell to us. He put the end of a length of hose into a large drum and sucked on it to draw gasoline into it. After spitting out gasoline from his mouth, he put the end of the hose into a metal pitcher on the ground. Gasoline drained into the pitcher. “Two gallons,” a painted label on the container said. I wondered what that meant to a Bolivian boy who probably had been schooled in liters, if at all. We asked for five pitchers of fuel. He repeated the siphoning of fuel four additional times. With a funnel in the van’s gas port, the boy poured each of the five pitchers of gasoline into the van’s tank. We paid the boy and were soon back on the road to La Paz.
Our plan for our studies in the Yungas was to drive to Coroico, identify our donors, get up early the next morning and collect our blood samples. We would then drive to Suapi and collect blood there before heading back to La Paz. One of Juliana Perez’s laboratory technicians would wait at INLASA for us, ready to work into the evening to help us process our samples. The cell culture studies we wanted to carry out at INLASA required viable cells, and that meant getting them separated from the blood and into approp
riate culture media without delay. We could not run out of gas again. “We’ll have to be sure to fill the van’s tank in Coroico every time,” I said to Gonzalo.
“Right, for sure.”
As the year progressed, our work went as smoothly as one might expect. The studies in Bolivian army recruits were done easily, and the results were encouraging. We were grateful to Colonel Suarez, who made arrangements for us and facilitated the work. Our results were about as we anticipated. Our rapid test worked well. And we found a goodly number of Bolivian soldiers with tuberculosis who were thus able to be treated.
The Yungas studies were less consistently productive. The cell studies gave variable results. Perhaps, we thought, because the cells were less viable than we had hoped they would be after the long hours of transport. In any event, variable results mandated larger numbers of individual experiments, and my sabbatical year ran its course before we could accomplish that. Be that as it may have been and accepting that most medical research has limitations imposed by circumstances, Gonzalo and I were satisfied with our year-long effort.
My medical school lectures were well received, I thought, and my Spanish fluency improved. In fact, my medical Spanish vocabulary rapidly expanded to meet the challenges of lecturing in that language. But there were interruptions when classes were cancelled, some for holidays, some for reasons I did not understand. One day I arrived at the medical school to find the place shut down and locked tight. I found a janitor and asked, “Is the medical school closed?”
“Of course. Pelé is here from Brazil playing futbol in the stadium.”
Escape Through the Andes Page 5