New Roads in the Amazon May Deliver Disease
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Nearly one-fifth of the Amazon rainforest has disappeared since 1970, its loss spurred by construction of roads through pristine areas. The loss of the trees is a big blow to the world's carbon balance, and a real force in climate change. And, according to three researchers from the Johns Hopkins Bloomberg School of Public Health, road construction in places like the Amazon might also be a blow to human health.
New roads promote deforestation. A recently published survey of the Peruvian Amazon by Paulo Oliveira of the Carnegie Institution of Washington and several colleagues shows that 75 percent of the forest disruption that occurred between 1999 and 2005 occurred within 12 miles of a road. And deforestation promotes malaria — researchers Amy Vittor and Jonathan Patz surveyed a newly constructed road and reported in 2006 that the areas along the road that had suffered more deforestation also suffered more malaria.
The Hopkins researchers want to follow the development of a road in real time. So they're surveying an area where the government is about to put in a highway. The road will go from the frontier river village of Mazan, through the Amazon jungle, to the city of Iquitos.
The researchers are infectious-diseases experts Margaret Kosek, a physician and former ultimate Frisbee player, and her husband, Pablo Yori. Yori is a gentle Spaniard, also an infectious-diseases expert. He keeps everyone going by carrying much of the gear. And there's biostatistician Bill Pan. Biostatisticians usually spend their time in front of computers. But Pan is outfitted for the jungle in a worn T-shirt he got when he was head of the cheerleading squad at Boston College. His six-foot two-inch frame is topped by a slouchy safari hat in camouflage colors.
Right now, the only route out of Mazan is by boat. The new road will bring in cars and trucks and people. The Hopkins team wants to see what this will do.
"I want to know how malaria is going to be affected by road construction, change in ecology, things like that," Pan says.
(Jane Greenhalgh, NPR)
The researchers figure this walk will take two days. It's a guess. Pan has brought the only maps they have — Google Earth photos from 2003.
"Today, the main goal is to map out the road, because we don't have any electronic data," he says.
Off the Path and Into the Woods
(Jane Greenhalgh, NPR)
The path out of Mazan threads past ramshackle brown plank houses, bright green grass and banana trees. There's already a manmade red clay gash where the road is going to go. The clay sucks at the researchers' boots.
They've been this far on other trips.
"It was a footpath before," Pan says. But now, he says, "you can see the tractor lines in the dirt."
Within minutes, they get to the two-story, bright yellow bulldozer responsible for turning the quiet footpath into a wide, mucky red path.
Pan has mixed feelings about the road development.
"The forest has a natural beauty to it and creating a road just ruins it," he says. On the other hand, he's talked to plenty of people who live in the area who see the road as progress.
But the road could also increase the number of mosquitoes that carry malaria.
"When roads are built, you can have culverts being formed along the road, little pools of water, streams and ditches," Pan says. These are ideal places for mosquitoes to lay their eggs.
And of course, the road will bring outsiders to villages that have been largely isolated.
If these newcomers carry malaria, mosquitoes could bite them, pick up the parasites and infect new victims.
At the end of the cleared path is a field of 10-foot-high, razor-sharp, chartreuse grasses. The two Peruvian guides whack a track with machetes. It's getting hot and muggy, and Kosek pushes everyone to keep hydrated.
The path looks a little easier in the jungle, and it's shady there. But the going is dense — the trees grow close together. Giant ferns struggle in the few spots of light. "This is the thick jungle right here," Pan says.
All the water bottles are empty now, so the scientists stop at a small dark pool and pump water through a filter. It's cool and good, but the stop gives a chance for mosquitoes to gather. It's fresh blood, and the mosquitoes are more than happy to take advantage of it.
"We're getting malaria ourselves," Pan says.
On their next trip through, the team will check how many of these mosquitoes actually do carry malaria.
A Sudden Downpour
With the mosquitoes and the close-set trees in the jungle, walking along the path where the road will be seems like a better idea. But it's not. The government cut trees along the planned highway route but has left them lying about like giant pick-up sticks. Every two or three steps, there are trunks and branches to climb over or under. And black clouds are racing in.
"It's going to rain," Kosek says. "It's 10 minutes to 6; we're not going to make it anywhere... Hopefully we have water nearby."
They set up camp in a clearing that looks like it once had been a village. But there's no one here now. In fact, they haven't seen anyone on the whole trip. No one could tell the researchers about their experiences with malaria or any other diseases.
Tents go up just in time. But Pan is trying out a tarp. "This is a good test to see if my tarp works," he says.
It doesn't. It leaks. Pan moves into Kosek and Yori's two-man tent, but it's too crowded. He ends up back under his leaky tarp.
The next morning Pan stands by the campfire, in shorts. "I'm drying my pants because they're very wet," he says.
The Route to Iquitos
The Hopkins researchers hope the discomforts will be worth it. If they can unravel the health effects of building roads through the jungle, they may find ways to prevent some of the problems. Because whatever the negative effects on health, on the forest, and on the atmosphere, there are benefits to a road.
But this morning, the challenge is just getting to Iquitos.
"Yesterday we walked 14 kilometers, and today we have to walk 28," says Pan. "So it's going to be a tough day today."
It is tough. More downed trees, more heat. Everyone is exhausted.
And then the guides find a well-worn path leading down to the river. The researchers decide enough's enough. Yori calls his office on his cell phone — service in Mazan just started a week previously. And he orders up a boat.
The walk down to the dock is easy. There are cleared fields and, for the first time, people. Farmers come out to see the strangers. The farmers say they're looking forward to the road. It will provide construction jobs, and it will help them get their goods to market.
Even though the hikers didn't make it all the way to Iquitos on foot, Bill Pan is satisfied with the trip. He's learned enough to plan the next steps of their work.
"I learned that the parts of the road that look on the satellite image as cleared are actually not as cleared as it appears. And there's not as many communities as we had thought there might be," he says.
When they come through next time, they'll be looking more at mosquitoes than at people. And instead of walking, they'll go by boat.
Produced by Jane Greenhalgh
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STEVE INSKEEP, host:
Many of you know that NPR's spending a year looking at the way that we're changing the climate and the way the climate is changing us. And this morning we consider collateral damage. Nearly one-fifth of the Amazon rainforest has disappeared since 1970. That's been spurred by construction of roads through pristine areas. The loss of the trees is a big blow to the world's carbon balance, and some scientists suspect that deforestation also changes the patterns of diseases. NPR's Joanne Silberner joined three young researchers in Peru for a hike into the jungle.
JOANNE SILBERNER: The first thing you should do before setting off on a journey through the jungle is buy a pair of boots.
(Soundbite of market transaction in Spanish)
SILBERNER: We're in a crowded market in the isolated town of Mazan near the Amazon River. Margaret Kosek is looking for knee-high black rubber boots.
Dr. MARGARET KOSEK (Researcher, Johns Hopkins Bloomberg School): Because this is gonna be wet and muddy.
S SILBERNER: A lot of it?
Dr. KOSEK: A lot of it.
SILBERNER: And the boots provide some protection from snakes, chiggers, and thorn trees. Kosek is 36, a physician, a former ultimate Frisbee player; she's wiry and strong. She and her husband, Pablo Yori, are infectious disease experts with the Johns Hopkins School of Public Health. They live in Peru. Another Hopkins researcher, Bill Pan, has flown in from the U.S. to join them. We're all going to hike the route of a highway being planned from Mazan down to the big city of Iquitos.
Dr. PABLO YORI (Researcher, Johns Hopkins Bloomberg School): Let's go, vamos.
SILBERNER: Right now Mazan is isolated; the only route in or out is the river. The new road will bring in cars and trucks and people. The Hopkins teams wants to see if this will lead to more cases of malaria.
Dr. BILL PAN (Biostatistician): How is malaria gonna be affected by road construction, changing ecology, things like that?
SILBERNER: We head out past ramshackle brown plank houses. Someone has just cut a broad swath through the bright green grass and banana trees. The red clay sucks at our boots.
Dr. PAN: So this is the beginning of the road and they've actually done a lot of clearing already.
SILBERNER: Pan is an unlikely explorer. Biostatisticians usually spend their time in front of computers. But here he is, 6'2" in a slouchy safari hat with water bottles hanging off his pack.
Dr. PAN: You can see the tractor lines in the dirt, so there's probably some kind of bulldozer or tractor just plowing through the forest tearing everything up.
SILBERNER: The researchers figure this walk will take two days. It's a guess. Bill Pan has brought the only maps they have, Google Earth photos from 2003.
Dr. PAN: For today the main goal is to map out the road, 'cause we don't have any electronic data on the road.
(Soundbite of nature)
SILBERNER: The path ends where a two-story-high, bright yellow bulldozer is tearing through ferns and bushes and trees.
Dr. PAN: So that forest has a natural beauty to it, and creating a road just ruins it.
SILBERNER: The road could also increase the number of mosquitoes that carry malaria.
Dr. PAN: When roads are built, you can have culverts being formed along the road, little pools of water.
SILBERNER: Streams and ditches, ideal places for mosquitoes to lay their eggs. And of course, the road will bring outsiders to villages that have been largely isolated.
Dr. PAN: One of the big issues with road construction is migration, local migration and temporary labor.
SILBERNER: If these newcomers carry malaria, mosquitoes could bite them, pick up the parasites and infect new victims.
(Soundbite of walking through grass)
SILBERNER: Razor-sharp grasses tower over our heads. Our two Peruvian guides are bushwhacking a track with machetes. It's getting really hot and muggy.
Dr. KOSEK: We need to keep on drinking water.
SILBERNER: We duck into the shade of the jungle. Tall trees with skinny trunks, thick trunks, block out the sky. We grab at vines as we pull ourselves through. Ferns struggle in the few spots of light.
Dr. PAN: This is the thick jungle right here, this is it. You can now say that you were definitely in the Amazon jungle.
SILBERNER: We run out of water. We stop at a small pool and pump the dark liquid through a filter. It's cool and good. Mosquitoes cloud around us, fresh blood.
Dr. PAN: Malaria, we're getting malaria ourselves.
SILBERNER: On their next trip through, the team will check how many of these mosquitoes do carry malaria. We rejoin the path where the actual road will be. The government cut trees along the planned highway route, but has left them lying around like giant pickup sticks. Every two or three steps, we have to climb over or under trunks and branches. We're not even a third of the way to Iquitos. Margaret Kosek looks at the black clouds racing in.
Dr. KOSEK: It's gonna rain. It's ten minutes to six, we're not gonna make it anywhere. So this is a flat place. So hopefully we have water near by. We've sent someone to go check.
SILBERNER: We set up camp in a clearing that looks like it once has been a village, but there's no one here now. In fact, we've seen no one so far. No one who could tell the researchers about their experiences with malaria or any other diseases. We get our tents up just in time.
(Soundbite of thunder and rain)
Dr. PAN: This is good; this is a good test to see if my tarp works.
SILBERNER: It does not. The tarp is not up to the weather. The next morning, Pan stands by the campfire in shorts.
Dr. PAN: I'm drying my pants 'cause they're very wet.
SILBERNER: The Hopkins researchers hope the discomforts will be worth it. If they can unravel the health effects of building roads through the jungle, there may be ways to prevent some of the problems. Because whatever the negative effects on health, on the forest, on the atmosphere, there are benefits to a road.
Dr. KOSEK: With roads comes electricity, comes a certain amount of businesses, comes many good things. There'll be better schools. There'll be better healthcare. But it also changes the uniqueness of the place, the quiet, the wildlife, the trees.
SILBERNER: But this morning the challenge is just getting to Iquitos.
Dr. PAN: Like yesterday we walked 14 kilometers and today we have to walk 28. So it's gonna be a tough day today. You ready?
Dr. KOSEK: Yeah.
Dr. PAN: Let's go.
SILBERNER: It is rough. More downed trees, more heat, everyone is exhausted. And then the guides find a well-worn path leading down to the river. The researchers decide enough's enough. We can get a boat to Iquitos. It's an easy walk to the dock. We see cleared fields and people.
(Soundbite of Spanish conversations)
SILBERNER: Farmers, like Pedro Lunio Sana(ph).
Mr. PEDRO LUNIO SANA: (Spanish spoken)
SILBERNER: He grows bananas, yucca, and rice.
Mr. SANA: (Spanish spoken)
SILBERNER: I can't wait for the road, he says. He'll be able to sell his goods in Iquitos. And at last we climb into a narrow wooden boat. Even though we couldn't hike all the way to Iquitos, Bill Pan is satisfied with the trip.
Dr. PAN: I learned basically that the parts of the road that are - that look on a satellite image as cleared are actually not as cleared as it appears. And there's not as many communities as we had thought there might be.
SILBERNER: And that next time, they should do the whole trip by boat. Joanne Silberner, NPR News.
INSKEEP: Our series Climate Connections has taken us around the world. And you can hear more stories in that series along with the latest on global warming from National Geographic magazine by going to npr.org/climateconnections.
(Soundbite of music) Transcript provided by NPR, Copyright National Public Radio.
