climatespreadofdisease
What we get wrong about Lyme disease.
The stories we tell about the epidemic get things backward.
BIOLOGY ENVIRONMENT
What We Get Wrong About Lyme Disease
The stories we tell about the epidemic get things backward.
BY KATHARINE WALTER
OCTOBER 5, 2017
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My sister Camilla and I stepped off the passenger ferry onto the dock at Vineyard Haven, Martha’s Vineyard’s main port, with a group that had already begun their party. They giggled, dragging coolers and beach chairs behind them. We competed to see how many items of Nantucket red we could spot.
Not that we were wearing any. Camilla wore shorts with white long underwear underneath, and I wore beige quick-dry hiking pants. Both of us had on sneakers with long white socks. It was late June, perfect beach weather. The water sparkled. But we weren’t headed toward the ocean. We were there to hunt for ticks.
On the island, we hopped in a cab. Camilla looked longingly out the window as we passed the turns for the town beach and Owens Park Beach. The driver pointed out the location of the famous shark attack beach from Jaws. We drove on south to Manuel Correllus State Forest, an unremarkable park in the center of the island and the farthest point from any beach.
THE GLAMOUR OF IT ALL: Camilla Walter harvesting deer ticks on Prudence Island, in Rhode Island’s Narraganset Bay. Tick collecting made Popular Science’s 2004 list of worst science jobs.Courtesy of the author
Deer ticks, or blacklegged ticks, are poppy-seed sized carriers of Lyme disease. We needed to collect 300 before the last ferry returned to Woods Hole, Massachusetts that night. We each unfurled a drag cloth—a one-meter square section of once-white corduroy attached to a rope—and began to walk, dragging the cloth slowly behind us as if we were taking it for a stroll. The corduroy patch would rise and fall over the leaves and logs in the landscape, moving like a mouse or a chipmunk scurrying through the leaf litter. Ticks, looking for blood, would attach to the cloth. Every 20 meters, we’d stoop to harvest them.
Tick collecting made it to Popular Science’s 2004 list of worst science jobs alongside landfill monitor and anal wart researcher. On cool days, though, sweeping the forest floor, kneeling to pluck ticks from corduroy ridges, the job became rhythmic. I felt strangely close to the forest. As I soon found out, the work got me closer to people, too.
The wilderness that we’ve feared, romanticized, and valorized is a fantasy.
Sometimes hikers would stop by, curious, then repulsed. They would want confirm the proper way to pull off ticks (with tweezers planted close to skin, perpendicularly), or to tell us about their diagnoses. Lyme disease isn’t like many of the diseases studied by my friends in the epidemiology department, where I was a doctoral student. No one talks about their grandmother’s syphilis infection, caused by Treponema pallidum, another spirochete bacterium.
But once people heard what Camilla and I were collecting, stories of brushes with ticks and family members’ diagnoses were shared freely. I quickly became the “tick girl.” When I started my dissertation I was preoccupied by the ecological question: How have humans altered the environment and triggered a disease emergence? By the time I finished, I realized that far more interesting were the rich and revealing tick stories shared with us along the way.
Illness makes us talk. “This is true of all forms of pain and suffering,” Arthur Kleinman, an anthropologist and physician at Harvard University, told me. We talk about illness “to seek assistance, care, and in part to convey feelings about fear, anxiety, or sadness.” In his book, The Illness Narratives, Kleinman writes that “patients order their experience of illness … as personal narratives.” These narratives become a part of the experience of being sick. “The personal narrative does not merely reflect illness experience, but rather it contributes to [it].”
The result is a peculiar togetherness. Once, a friend’s mom emailed that she’d just pulled off her first tick of the season, from her pubic hair: “I’m guessing it doesn’t it surprise you to hear, Katie, that you came to mind almost immediately when I discovered the little bugger? I’m afraid that ticks and you will be forever linked in my mind.” Naturally some took the motif too far. One creepy grad student thought that, because I was standing in front of a tick poster at an academic conference, I’d want to hear about the time he pulled a tick off his dick.
By dosing ourselves, we gain control.
The country singer Brad Paisley romances the tick: “I’d like to see you out in the moonlight / I’d like to kiss you way back in the sticks / I’d like to walk you through a field of wildflowers / And I’d like to check you for ticks.” I’m with Paisley here. Creeps aside, tick grooming is an act of love. My sister and I were diligent in the tick checks we gave ourselves and each other. Most nights, we’d pull off several at the campsite showers.
Tick stories mostly fell into a few categories. There were the boastful ones. On Washburn Island, a tiny island a few hundred yards off of Cape Cod, two hairy, fully-bearded park rangers, Steve and Steve, couldn’t be bothered to pull off their ticks. For most of the summer, they lived outside in tents and tarps and always had a few handfuls of ticks embedded in their skin. The Steves boasted that they’d each been infected with Lyme disease and babesiosis, a parasitic illness also carried by deer ticks, on and off for the last several years. Theirs was a backcountry machismo, as if their burliness made them immune to the intrusion of the forest twigs and ticks upon their bodies. Their symptoms, though, were presumably as real as anyone else’s.
The bulk of people’s reactions to the disease reflected a confused anxiety about boundaries. En route to a wedding in Easton, Connecticut, deep in Lyme country, someone found out that I was a tick girl and asked if they should be worried. The wedding was on a farm, an edge habitat where weedy species—mice, chipmunks, and robins—proliferate. Weedy animals include some of the best hosts for the Lyme disease bacterium. They can be infected with a tick bite and pass on the bacterium to the next tick that feeds on them, continuing unbroken chains of transmission. Deer, which are also hosts for ticks, thrive in these fragmented habitats, too.
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I recited my usual tick check endorsement: Shower and check yourselves at the end of the night and you’ll be fine. The Lyme bacterium is only transmitted after the tick has been attached for two or three days. Still, when guests filled the lawn for corn hole and cocktails, I couldn’t help but notice all the cocktail dresses and open heels, ankle-deep in grass. The next morning, one woman told me she’d plucked three ticks from her ankle.
Worry bled to fear. On Cuttyhunk Island, the most remote of the Elizabeth Islands, a necklace of islands spilling off of southern Cape Cod, my sister and I were generously hosted by a woman I’ll call Susan, a self-trained student of the Lyme epidemic. “Ticks have become the bane of island existence,” Susan gravely told me shortly after I arrived. By 2010, everyone Susan knew on the island was taking doxycycline, the antibiotic most commonly prescribed for Lyme disease. She and her husband arrive in Cuttyhunk at the start of the summer season armed with bottles of it and take it prophylactically. Every time they pull off a tick, they take three doses, spread over 24 hours. This is not recommended by the CDC (the Centers for Disease Control and Prevention). Doxycycline makes your skin sensitive to the sun, so their regimen makes it necessary to wear a hat and lots of sunscreen or stay inside.
Susan fenced in her lawn to keep out rabbits, which can host adult ticks, then raised the fence to defend against deer. “Our house is ringed with Damminix tubes, the yard fenced, grass mowed short, and still they turn up in the bed with us,” she told me. (Damminix tubes hold cotton infused with an insecticide that kills ticks.) We slept in her son’s room, crisp and nautically themed and lined with file cabinets full of scientific articles about Lyme disease epidemiology and ecology, local and national reporting on the epidemic, and printed email exchanges with epidemiologists and local politicians. Susan is now spearheading the island’s Tick Eradication Campaign. Her plan for eradication was ambitious, she admitted. But, she asks: “Wouldn’t it be nice to be able to say that you are stepping onto a tick-free island where a sunburn is the most dangerous health risk?”
The idea that the natural and human exist in separate realms is the very “trouble with wilderness,” the environmental historian William Cronon wrote in his 1995 book Uncommon Ground. The wilderness that we’ve feared, romanticized, and valorized over the last few hundred years, he says, is a fantasy:
[Wilderness] is quite profoundly a human creation—indeed, the creation of very particular human cultures at very particular moments in human history … Wilderness hides its unnaturalness behind a mask that is all the more beguiling because it seems so natural. As we gaze into the mirror it holds up for us, we too easily imagine that what we behold is Nature when in fact we see the reflection of our own unexamined longings and desires.
In the stories told by our doctors, our parks, and the CDC, ticks are invaders. To defend ourselves, we use insect repellent, clothing, and prophylactic antibiotics; fences, signs, and pesticides. “When it comes to pesticides, the environmental toxin par excellence, Lyme patients are often its greatest proponents,” writes Abigail Dumes, an anthropologist at Michigan State University. We prefer the risk posed by pesticides to the fear of Lyme, Dumes explained to me. They let us become actors instead of victims. By dosing ourselves with pesticides (or antibiotics), we gain control of our risks. Ticks, on the other hand are uncontrollable. “It’s difficult to live with the idea that there are enormous threats and many can’t be controlled,” Kleinman tells me.
The problem is our defensive barriers aren’t working particularly well. Deer ticks are now established across 45 percent of United States counties. Their range has more than doubled in the last 20 years. Reported cases of Lyme disease have more than tripled since 1995 and the CDC estimates that more than 300,000 Americans fall ill each year. The story of tick-as-invader isn’t particularly helpful—or complete.
LYME EMERGES: Allen Steere and Stephen Malawista published these maps of Lyme disease in 1979, just two years after it had been named. They noted a correspondence between disease clusters and areas where two species of black-legged ticks were known to exist.Courtesy of the author
In November 1975, Polly Murray, an artist living in Lyme, Connecticut, contacted the Connecticut State Department of Public Health. Two of her children were sick with what doctors called juvenile rheumatoid arthritis, a disease of joint pain. Their knees were so swollen that they were forced to walk with crutches. Several other neighborhood children had similar symptoms. Arthritis is rare in children. And it is not normally found in clusters. So Murray kept careful notes of her children’s symptoms and compiled a list of other sick children.
At first, doctors were dismissive. But Allen Steere, a young rheumatologist at Yale-New Haven Medical Center, was curious. He began to investigate cases in Lyme, Old Lyme, and East Haddam, quiet, wooded communities just east of the mouth of the Connecticut River. Through a surveillance “grapevine,” he found 51 residents—39 children and 12 adults—in a community of 12,000 suffering from unexplained arthritis. A quarter of patients also had erythema migrans, an expanding circular rash with a pale center, also called a bullseye. In some neighborhoods, 10 percent of children suffered from this unexplained arthritis. In 1977, in the journal Arthritis and Rheumatism, Steere and his team named the set of symptoms Lyme arthritis. They called it “a previously unrecognized clinical entity.”
If anyone is an invader here, it’s us.
At that point, what caused the symptoms remained a mystery. The clustering of cases suggested the new disease was infectious, and the summertime peak of cases suggested it was spread by something in the water—picked up by swimmers—or by insects. Steere’s team tested his patients’ blood for dozens of viruses and bacteria. Nothing fit. In 1979, Steere and a colleague mapped out the first 512 cases of Lyme arthritis. The distribution of cases overlapped neatly with what was then the range of deer ticks. Many of Steere’s patients lived in wooded areas and had mentioned insect bites. But hundreds of ticks were tested and no pathogen was found.
A few years later, William Burgdorfer, an entomologist at the Rocky Mountain National Laboratories, identified a new spirochete—a corkscrew shaped bacterium, capable of spiraling through the tissues of its hosts—in ticks collected from Shelter Island, a tiny island nestled between the two pointer fingers of Long Island. Sixty percent of ticks collected on the island carried the bacterium. Soon after, spirochetes were found in the blood of people suffering from Lyme arthritis. The Lyme disease bacterium, Borrelia burgdorferi, was named in his honor. It cycles silently in forests between ticks and a group of hosts, mostly small rodents and birds. From the perspective of the bacterium, humans are dead-end hosts and play no role in the spread of disease to new areas.
The modern history of the disease is relatively short: Just 40 years have passed since it was named. This can contribute to the sense that it is a new invader into our pristine neighborhoods and parks. But where did the bacterium come from? Was it truly new? And why did it first appear in a bucolic Connecticut suburb?
Spreading ticks and migrating bacteria leave no trace on the environment. Unlike pathogens that spread strictly from human to human (like measles), we cannot trace the history of the Lyme disease bacterium from the history of human epidemics. So, in 1990, biologists turned from medical records to museums. They sifted through old ticks in entomology collections at Harvard University and the Rocky Mountain National Laboratories, testing for bacteria. They found ticks infected with B. burgdorferi collected in the 1940s in Montauk Point and Hither Hills, parks near the Hamptons on the eastern tip of Long Island. Museum collections held no ticks before the 1940s.
That effectively doubled the known history of the disease. Then, researchers turned to the hosts themselves. They snipped ear punches from mouse specimens at the Smithsonian Museum, the Natural History Museum in New York, and the Harvard Museum of Comparative Zoology. Mice from Cape Cod in the 1890s turned out to be infected. Now the disease had a century-long history. Scientists studying Ötzi, the Tyrolean Iceman, stumbled upon in 1991 by hikers in the Italian Alps, have found that he was lactose intolerant, had intestinal parasites, severe atherosclerosis—and probably had Lyme disease. This meant the bacterium likely existed in western Europe 5,000 years ago.
PIERCING: The hypostome of a deer tick is a piercing organ with recurved teeth.Ed Reschke / Getty Images
To extend the history of the bacterium further back still, my advisors, Maria Diuk-Wasser and Gisella Caccone, and I turned to the 1 million letters of the bacterium’s genome. Pathogens evolve as they spread, and their genome carries a historical record of this development. By comparing pathogen genomes collected from different areas, we can build an evolutionary tree and a history of the pathogen’s spread. We can also tell how big the population of pathogens is now, and whether it is growing. This is the crux of phylogeography: Use evolutionary relatedness to answer questions about biogeography, the historic and spatial distribution of genetic diversity. A classic finding in the field, for example, is that the HIV epidemic originated in the French or Belgian Congo around the 1920s.
I began to chase bacteria from as wide an area and from as far back in time as possible. Biologists mailed me ticks in tiny tubes of ethanol from Michigan, Wisconsin, and Virginia. A Styrofoam container filled with dry ice and DNA samples of infected ticks collected across Canada was Fed-Exed to me. Old ticks were harder to come by. At the Yale Peabody Museum of Natural History, I pulled out drawer after drawer of taxidermied Peromyscus leucopus, white-footed mice, elegantly arranged in rows, with handwritten labels tied around their right ankles. Many were collected in the 1800s, when natural history museums were filled with hunting trophies. But the taxidermist had been tidy. The mouse skins had been cleaned of ticks. The oldest ticks I could find that were infected and had well-preserved DNA were from the early 1980s. Camilla and I added them to the 7,000 ticks from our summer harvest.
Finally, with 150 complete genomes in hand, my colleagues and I were able to extend the North American history of Lyme disease from a hundred years to many thousands. We drew a new evolutionary tree which showed that the bacterium likely originated in the northeast of the U.S., spreading south and west across North America to California. Birds likely transported it long distances to new regions, where small mammals continued its spread. Imprinted on the bacterial genomes was also a signature of dramatic population growth. As it evolved, it seemed to have proliferated.
Most interestingly, the tree was far older than we’d expected—at least 60,000 years old. Lyme was likely here in North America much longer than that, long before it was first named in the 1970s, long before humans first arrived in North America from across the Bering Strait (about 24,000 years ago), and long before the last glacial maximum, when much of North America was covered by an ice sheet (also about 24,000 years ago). If anyone is an invader here, it’s us. Our analysis also showed that the modern epidemic was not sparked by some new mutation that made the bacterium more readily transmissible. It was sparked by changes in ecology, most of which were man-made.
When colonists first arrived in New England, much of the area was forested. White-tailed deer were abundant. Deer ticks, whose distribution is closely tied to that of deer, most likely existed throughout much of the continent, too. Colonists pressed and pleated the complex fabric of New England’s forests, grasslands, and swamps into a starched blanket of fenced farmlands. Hunting and deforestation decimated deer populations. By the mid 18th-century, deer had almost entirely vanished. They never disappeared, though. Deer—and likely, deer ticks and B. burgdorferi—persisted in refugia, isolated pockets of southern Cape Cod and the far eastern tip of Long Island. Some deer populations were carefully cultivated. In 1698, hunters stocked the Naushon Island, one of the Elizabeth Islands (a few islands north of Susan’s Cuttyhunk) with deer. The island soon became a glamourous hunting destination and was purchased by the Forbes family in 1856, whose annual hunting party was attended by Ralph Waldo Emerson and Herman Melville, among others. The earliest record of a deer tick in the northern U.S. was on Naushon Island in 1926.
Beginning in the mid 1800s, farming gradually shifted westward and New England slowly reforested. But only shreds and slivers of forest were allowed to regrow. Deer populations rebounded and the animal spread across a transformed, suburban New England, one in which wolf predators had been exterminated, and where deer hunting was strictly limited. Ticks followed the deer, and B. burgdorferi followed the ticks. The sprawling grassy suburban lawn adjacent to a forest patch is the ideal Lyme disease habitat. The majority of tick-borne infections occur here because excellent hosts for B. burgdorferi also thrive in these manufactured edge habitats. More recently, climate change has been warming our winters, accelerating ticks’ life cycles and extending their range eight miles farther north each year.
The genetic and ecological history of the Lyme disease bacterium make it clear: Neither ticks nor the bacterium are invaders onto our pristine landscapes. They are the beneficiaries of an artificial and fragmented ecology created by the real invaders, us. Having sectioned and sliced the continent into a patchwork, we are confronted with the consequences. “Many of the individuals I spoke with during the course of my fieldwork moved to or remained in forested suburbs to be ‘close to nature,’ ” writes Dumes. “But ‘after Lyme,’ many described an experience of becoming ‘prisoners of their own paradise.’ ”
We’ve built structured domestic spaces on the periphery of the natural world to help us keep alive our fantasy of a wilderness that is pristine but kept at a safe distance. Ticks put the lie to that fantasy. They make us pay attention. They force us to notice and explore the freckles and spots of dirt on our ankles and our partners’ ankles. They force us to observe the spaces around us. They are rude reminders that there is no such thing as wilderness untouched by humans or humans detached from nature.
That’s a better story than tick-as-invader. This history doesn’t offer a tidy answer for how to stem the epidemic. But it shows us that our modern response to Lyme disease—to build more boundaries—echoes the impulse that created the epidemic in the first place. It’s not a just problem with Lyme. I defended my doctoral work earlier this year and am now studying another artificial boundary—the one between prisons and the free world—that is creating another epidemic: tuberculosis. My study sites have moved from Martha’s Vineyard to Brazilian prisons, but in a few ways, the new disease stories I’m encountering are alarmingly familiar.
Katharine Walter is a postdoctoral fellow at Stanford University.
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Desperation grows in Puerto Rico’s poor communities without water or power.
The health crisis is intensifying two weeks after Hurricane Maria, and government aid is slow. 'We could see significant epidemics,' a health expert warned.
BY PHIL MCKENNA
FOLLOW @MCKENNAPR
Public health conditions are rapidly deteriorating across Puerto Rico as government agencies struggle to restore basic services such as power and clean drinking water and deliver emergency supplies two weeks after Hurricane Maria ravaged the U.S. territory. The situation is dire across much of the island but even more so for its most vulnerable, low-income minority communities.
Only about half the territory's residents had access to potable drinking water, and electricity had been restored to just 5 percent of Puerto Rico as of Tuesday, when President Donald Trump visited the capital, San Juan, according to the Federal Emergency Management Agency.
"The sense of desperation is only growing with every passing day," said Chris Skopec, executive vice president for global health and emergency response with Project HOPE, a Millwood, Virginia-based nonprofit now working in Puerto Rico. "In these kinds of conditions, the ability for an epidemic to spread is really ripe."
In Caño Martín Peña, a densely populated community of mostly wooden homes originally built by impoverished squatters in a flood zone in the heart of San Juan, existing public health issues were exacerbated by the storm.
The community is plagued by untreated sewage that flows into the adjacent Martín Peña Channel. Before Hurricanes Irma and Maria, even moderate rainstorms would cause the debris-clogged channel to overflow, sending raw sewage into basements and causing skin rashes and asthma. Outbreaks of mosquito-borne diseases dengue and Zika are common in the community of 23,000, where 25 percent of adults are unemployed and the median household income is $13,500, according to 2010 U.S. Census data.
"People are drinking whatever comes from the faucet, and it's turbid," said Lyvia Rodríguez del Valle, executive director of the Caño Martín Peña Land Trust Project Corporation, a public-private partnership working with the community. "People lost their roofs. They cannot close their doors, so we are having issues with mosquito bites and other insects, we are having plagues like rats and everything else."
Volunteers from outside aid organizations have helped clear trees and other debris from the streets, but the government response is just starting, Rodríguez del Valle said. Government officials provided an initial delivery of 60 blue tarps on Sunday to the community where 800 families lost their roofs. City garbage trucks began removing debris piles the same day.
"We have barely seen the government here," Rodríguez del Valle said.
More than 12,300 federal staff representing 36 departments and agencies are now on the ground in Puerto Rico and the U.S. Virgin Islands engaged in response and recovery operations, according to FEMA.
'We Could See Significant Epidemics'
Rodríguez del Valle said the mosquito bites that have been reported in Caño Martín Peña in recent days suggest diseases like dengue, Zika or chikungunya, which take several days or longer to surface after the initial bites, are on their way.
Health experts say mosquito- and water-borne diseases present a serious concern for all of Puerto Rico.
"Unless there is massive intervention to implement some type of health infrastructure, we could see significant epidemics in the coming weeks," said Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston.
"I'm concerned about typhoid, paratyphoid and shigella [bacterial diseases that can spread through non-potable water] on the diarrheal side and the vector-borne diseases, especially dengue, because we have dengue in Puerto Rico every year anyway," Hotez said.
Twenty miles east of San Juan in Loiza, a coastal community where 65 percent of residents are black and and nearly half of residents live below the poverty level, there are already reports of diarrheal diseases.
"We are seeing increasing rates of gastrointestinal disease as there are increasing reports of people drinking river water, and otherwise unable to access clean water," Skopec, of Project HOPE, said. "It's a very bad situation and the outlook is that it's going to continue to get worse before it gets better."
Skopec, whose organization is operating a mobile clinic and conducting home visits in the town, said the exact cause of the disease is not known.
On Radio, Hospitals Beg for Fuel for Generators
South of San Juan in Salinas, a low-income community largely of African descent on the Caribbean Coast, community leaders say they have received little outside assistance.
"The hospitals are on the radio asking for diesel and fuel to run their generators," said Ruth Santiago, an environmental lawyer for Comité Diálogo Ambiental, Inc. (Environmental Dialogue) in Salinas. "Elder centers, they are asking families to pick up their relatives."
In an address in Puerto Rico on Tuesday, President Trump praised his administration's response to the storm and compared Hurricane Maria, where the early reported death toll from the hurricane was 16 people, to what he called a "real catastrophe like Katrina" where thousands died.
The governor of Puerto Rico raised the official death count to 34 after Trump left, but that, too, is likely low. Puerto Rico's Center for Investigative Journalism reported that morgues are at capacity, the official system for registering deaths is barely functioning, and the number could rise into the hundreds due to the territory's damaged health care infrastructure.
Leaving Home Behind: 'You Try to Be Strong'
Santiago has driven back and forth to San Juan four times in the past two weeks since Maria made landfall, but she said she is only starting to see military and other supply vehicles on the roads in recent days.
"I don't know why were are not getting the kinds of things that are basic necessities 13 days out from Hurricane Maria," Santiago said. "I know many people who are getting airline tickets and they are just leaving."
Airlines are now offering reduced airfares for those seeking to leave the island, though commercial flights remain limited after Maria severely damaged radar equipment at the main airport, in San Juan.
Cruise ship company Royal Caribbean International offered free passage to thousands of evacuees from Puerto Rico and the U.S. Virgin Islands aboard a ship that arrived in Fort Lauderdale on Tuesday.
For those who evacuate the region and those who remain, many will have to cope with mental health issues related to the storm.
Marcella Chiapperino lost her home and business in Frederiksted, St. Croix, in the U.S. Virgin Islands, to Hurricane Maria after both had been battered by Hurricane Irma two weeks before. Chiapperino said she had her first real night of sleep after boarding the Royal Caribbean ship last Thursday but was still haunted by nightmares. "I was woken up by a dream of this wave coming and wind and pulling me outside the window," she said. "It just sucked me out."
"You try to be strong," she said, "but I think a lot of people will have some kind of post traumatic experience from this."
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One more thing for Puerto Rico to worry about: Disease-ridden mosquitoes.
Experts say the combination of natural disasters and persistent socioeconomic inequality creates an environment where mosquito-borne diseases — such as dengue, chikungunya and Zika — can spread.
The images and reports coming out of Puerto Rico show an island in crisis. Many ports remain closed, airports are damaged, and roads are blocked by debris or have been washed away by floods. Electricity will likely be gone for months. Internet and phone service have become luxuries. Homes lie in ruins across the island.
The natural disaster has drawn attention to deeper political and financial inequalities between Puerto Rico — a U.S. territory — and U.S. states such as Florida and Texas, which are having an easier time returning to normal after their recent hurricane experiences. Unfortunately, there could be more trouble ahead, in the form of tiny tropical mosquitoes. Experts say the combination of natural disasters and persistent socioeconomic inequality creates an environment where mosquito-borne diseases — such as dengue, chikungunya and Zika — can spread.
All those diseases exist in Puerto Rico in the background of everyday life, occasionally flaring up into full-blown epidemics. Dengue, a virus that causes fever and joint pain, was diagnosed in 174 people in Puerto Rico in 2016 and none in the first half of 2017. But in bad years — 1994, 1998, 2007 and 2010, among them — it has infected more than 10,000. The same is true of other mosquito-borne diseases on the island. Zika, infamously, was epidemic in 2016, with more than 40,000 people diagnosed in Puerto Rico. By this June, though, cases of the disease had fallen to nearly nothing, and the epidemic was declared over.
It’s not always clear what factors make the difference between a year in which mosquito-borne disease is negligible and one in which it’s epidemic. But hurricanes alone aren’t necessarily big predictors, said Ben Beard, deputy director of the Centers for Disease Control and Prevention’s Division of Vector-Borne Diseases. The floods and winds that come with a storm kill mosquitoes and wash away their breeding grounds, and it’s not uncommon for a big hurricane to disrupt an outbreak in progress by temporarily cutting the local mosquito population off at the knees. But that effect is short-lived. “Within a week or so, you tend to see the situation come back to where it was before the storm,” he said. “Several weeks after that, you’ll see some increase.”
At that point, it starts to matter how a society has weathered the storm and how quickly it is recovering. The longer people live without solid roofs, intact window screens and air conditioning — and the longer they’re forced to spend large amounts of time outdoors rebuilding — the more likely it is that a storm will, indirectly, bring people and insects together.
Take, for instance, the connections between Hurricane Katrina and West Nile virus. This virus, carried by mosquitoes, already existed in Louisiana and Mississippi. But a 2008 study by Tulane University found that, in the weeks after Katrina passed through, hurricane-affected counties saw a two-fold increase in cases. Meanwhile, in counties that avoided the worst of the storm, cases of West Nile either went down or stayed the same. The increase was probably partially due to a burst of mosquito breeding in stagnant pools the storm left behind, said Peter Hotez, dean of the National School of Tropical Medicine at Baylor University.
But mosquitoes don’t create an outbreak by themselves. To spread disease, you need people coming into contact with those mosquitoes. As the Tulane study noted, tens of thousands of hurricane survivors spent weeks in damaged homes or outside, waiting to be evacuated. The storm gave mosquitoes breeding grounds. Political disorder ensured that those new insects had access to humans.
Socioeconomic inequality — and the quality-of-life differences it creates — can have a big impact on who contracts mosquito-borne disease, even in the absence of a natural disaster, said Samuel Scarpino, a math professor at the University of Vermont who studies disease surveillance.
In 2003, researchers in the U.S. and Mexico analyzed the spread of mosquito-borne dengue virus in Laredo, Texas, and its cross-border neighbor, Nuevo Laredo, Mexico. The two towns had, effectively, the same climate and geography, though the Texas town had more mosquitoes breeding around local homes.
But it was the Mexican town that had much higher rates of residents whose blood tested positive for dengue exposure. Researchers connected that difference to disparities in living conditions between the two Laredos. Texans were much more likely to have central air conditioning, intact window screens and other little luxuries that created a barrier between them and the local mosquitoes.
Findings like this have big implications for Puerto Rico, Scarpino said. The loss of electricity on most of the island could mean that most Puerto Ricans — even those who escaped the worst of the storm — will spend the next few months with no air conditioning. Instead, like the citizens of Nuevo Laredo, they’ll rely on windows to cool homes, schools, offices and government buildings — windows that are likely to have screens damaged by the storm.
What’s more, Scarpino told me, the loss of electricity and other forms of infrastructure is also likely to affect Puerto Rico’s mosquito-borne disease surveillance system. Scarpino recently published research analyzing that system, and he said it was one of the most impressive in the world because of its mosquito control and capture, high rates of disease testing and reporting, and molecular diagnostics that allow for quick, accurate test results. But those things rely on infrastructure lost to the storm: passable roads for trapping and collecting mosquitoes; intact hospitals and money for people to visit when they have fevers; electricity to power the diagnostic laboratories.
In other words, the impact of a hurricane isn’t just about the storm, it’s also about the place it hits. Puerto Rico’s political status, and its long-running economic and infrastructure crisis, could put its residents at risk of health problems that a U.S. state with a stronger economy wouldn’t have to worry about. And that’s not a huge surprise. Ultimately, Scarpino told me, this fits squarely into what we know about how diseases, in general, spread: “The biggest predictors are inequality and socioeconomic status.”
Maggie Koerth-Baker is a senior science writer for FiveThirtyEight.
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Move over malaria: Mosquitoes carrying Zika, dengue may thrive in warmer Africa.
Hotter weather and migration to cities may make different diseases the scourge of the future in Africa, scientists say.
by Kieran Guilbert | KieranG77
DAKAR, Sept 22 (Thomson Reuters Foundation) - From deadly droughts and destroyed crops to shrinking water sources, communities across sub-Saharan Africa are struggling to withstand the onslaught of global record-breaking temperatures.
But the dangers do not end there. Rising heat poses another threat - one that is far less known and studied but could spark disease epidemics across the continent, scientists say.
Mosquitoes are the menace, and the risk goes beyond malaria.
The Aedes aegypti mosquito, which spreads debilitating and potentially deadly viruses, from Zika and dengue to chikungunya, thrives in warmer climates than its malaria-carrying cousin, known as Anopheles, say researchers at Stanford University.
In sub-Saharan Africa, this means malaria rates could rise in cooler areas as they heat up, but fall in hotter places that now battle the disease. In those areas, malaria - one of the continent's biggest killers - may be rivalled by other vector-borne diseases as major health crises.
"As temperatures go past 25 degrees Celsius (77 degrees Fahrenheit), you move away from the peak transmission window for malaria, and towards that of diseases such as dengue," said Erin Mordecai, an assistant professor at Stanford.
"We have this intriguing prospect of the threat of malaria declining in Africa, while Zika, dengue and chikungunya become more of a danger," she told the Thomson Reuters Foundation.
Besides a warming planet, scientists fear growing urbanisation across Africa could also fuel the transmission of diseases carried by the Aedes aegypti mosquito, which flourishes in cities and slums - the opposite of the country-loving Anopheles.
One in two Africans are expected to live in cities by 2030, up from 36 percent in 2010, according to World Bank data.
A soaring number may become prey to vector-borne viruses like dengue, which have struck Africa at a record pace in recent years, fuelled by urbanisation, population growth, poor sanitation and global warming, the World Health Organization (WHO) says.
"We see poorly planned development in Africa, not just with megacities but smaller settlements ... which often lack proper water and sanitation," said Marianne Comparet, director of the International Society for Neglected Tropical Diseases.
"Climate change, disease and the interaction between man and habitat - it is a crisis going under the radar ... a time-bomb for public health problems," she added.
NEGLECTED DISEASES
Last year was the hottest on record, for the third year in a row, with global temperature rise edging nearer a ceiling set by some 200 nations for limiting global warming, according to the European Union's climate change service.
Parts of Africa were among the regions suffering from unusual heat.
As temperatures keep rising, mosquitoes in low-latitude regions in East African countries are finding new habitats in higher altitude areas, yet malaria rates are falling in warmer regions, such as northern Senegal in the Sahel, studies show.
So as cooler parts of sub-Saharan Africa gear up for the spread of malaria, hotter areas should prepare for future epidemics like chikungunya and dengue, experts say.
While not as lethal as malaria, chikungunya lasts longer and can lead to people developing long-term joint pain. Dengue causes flu-like symptoms and can develop into a deadly hemorrhagic fever.
There is a danger that the global drive to end malaria, which absorbed $2.9 billion in international investment in 2015, has left African countries ill-prepared to deal with other vector-borne diseases, said Larry Slutsker of the international health organisation PATH.
"Diseases such as dengue and chikungunya have been neglected and under-funded," said Slutsker, the leader of PATH's malaria and neglected tropical diseases programmes. "There needs to be much better surveillance and understanding."
Malaria kills around 430,000 people a year, about 90 percent of them young African children.
Dengue, the world's fastest-spreading tropical disease, infects about 390 million annually but is often badly recorded and misdiagnosed, health experts say.
Some experts believe the global alarm triggered by Zika, which can cause birth defects such as small brain size, may see more money pumped into fighting neglected tropical diseases in sub-Saharan Africa, especially after outbreaks in Angola, Cape Verde and Guinea-Bissau during the last year.
Although 26 African nations - almost half of the continent - have strategies in place to fight vector-borne diseases, most of them only target malaria, according to data from the WHO.
Malaria rates have been slashed in recent decades through the use of bed nets, indoor spraying and drugs. But there are no dedicated treatments or vaccines for chikungunya and dengue.
"The most important preventive and control intervention is vector management, particularly through community engagement," said Magaran Bagayoko, a team leader for the WHO in Africa.
DISENTANGLING DATA
However, efforts to beat back mosquitoes are hampered by a lack of quality and affordable climate data that could help predict outbreaks and indicate risks, said Madeleine Thomson of the International Research Institute for Climate and Society.
"What countries really want to know is what they can do to improve their programmes, as well as the capacity of their health workers," said the scientist at the Columbia University-based institute.
But to do that, "climate information must be put into practice", Thomson added.
African nations also must improve coordination between their health ministries and meteorological agencies, said the Africa Centers for Disease Control and Prevention (Africa CDC), a new continent-wide public health agency launched this year by the African Union.
"They are not linked, or talking to each other," said Sheila Shawa, a project officer at the Africa CDC headquarters in Ethiopia. "There needs to be better communication in order to model neglected diseases, such as chikungunya, across Africa."
Yet climate scientists and health experts warn of the difficulty of analysing the impact of rising temperature on mosquito-borne diseases without looking at other factors.
"We have a major challenge of isolating effects of rising temperatures – which are really variable – from all the other aspects like rainfall patterns, humidity, mobility and migration, as well as socioeconomic factors," said Stanford's Mordecai.
"They are all changing at the same time, making individual drivers very difficult to isolate and disentangle for analysis."
(Reporting by Kieran Guilbert, Editing by Laurie Goering and Megan Rowling; Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking, property rights, climate change and resilience. Visit https://news.trust.org)
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Climate change is already making people sicker.
Climate change is a central issue at this year’s United Nations General Assembly, with multiple high-level meetings on the issue happening amid several devastating natural disasters.
Factory chimneys in smoke
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CLIMATE CHANGE
Climate Change Is Already Making People Sicker
Alexandra Sifferlin
Sep 20, 2017
TIME HealthFor more, visit TIME Health.
Climate change is a central issue at this year’s United Nations General Assembly (UNGA), with multiple high-level meetings on the issue happening amid several devastating natural disasters. Hurricane Irma recently swept through the Caribbean and into Florida, only to be quickly followed by Hurricane Maria.
“Climate change casts a long shadow over the development efforts of our country,” said Darren Henfield, the minster of foreign affairs of the Bahamas, during a UNGA meeting on Hurricane Irma. “The implications of rising sea levels and atmospheric temperatures signal dire consequences for low-lying island states like the Bahamas.” Henfield said that the costs of rebuilding after Irma will be “exorbitant, in the tens of millions,” and he estimates similar damage related to Hurricane Maria.
The impact of climate change on global health is also becoming increasingly clear. At the end of last week, the United Nations released a report showing that global hunger is on the rise; 38 million more people were affected in 2016 than in 2015. Climate change and the spread of violent conflicts are responsible, the report says. Other research has linked climate change to increased respiratory problems, poor nutrition, the spread of infectious disease and even anxiety.
Leaders at the UN say that while more countries are explicitly calling out these risks to health now than in the past, there’s still more work to do. “I think it’s clear quite a few countries, particularly in the developing world where air pollution is high, see that there is an opportunity to reduce climate change and improve health,” said Nick Nuttall, spokesperson for the United Nations Framework Convention on Climate Change (UNFCCC) during an interview Wednesday. “But the issue still has a ways to go.”
The recent tragic weather events have provided an opening for those conversations. “These hurricane or flooding events have huge implications for water quality,” says Nuttall, citing the risk for things like sewage and other chemicals to get into floodwater and spread. The risk for mosquito-borne diseases ranging from dengue fever to Zika can increase as floods recede, leaving breeding grounds for mosquitoes and other insects.
“Major health benefits come from acting on climate change, both direct and indirect,” says Nuttall. Preventing deforestation limits flooding, which cuts back on the number of pests like mosquitoes that can accumulate and spread diseases, he says.
The issue affects the oceans, as well. “If we lose our coral reefs, we lose revenue for countries, but also fish, which is an important source of protein,” says Nuttall.
MORE: Why Global Health Is Center Stage at the United Nations General Assembly
Climate change has been a popular subject at this year’s UNGA, and many leaders have publicly reaffirmed their commitment to tackling the problem. But the U.S.'s position on the issue has changed from last year. In June, President Donald Trump withdrew the United States from the Paris Agreement on climate change.
Other U.S. leaders, including California governor Jerry Brown and former vice president Al Gore, took part in UNGA meetings about climate change and assured attendees that other leaders are still addressing the issue.
“We are a country of diverse power centers, and mobilizing those power centers that are not controlled by the President is still a very worthwhile goal and very powerful," said Brown during a high-level stakeholder meeting on climate change on Monday. "Mayors, governors, presidents and CEOs of companies: they have real power."
“It would be great if the President would join in the movement," Brown said, but "he's not there yet. He believes this whole thing we're talking about, all the scientists publishing thousands of papers, is all a hoax.”
There are signs that UN leaders are open to engaging with other leaders beyond the U.S. federal government. “The decision [by the U.S.] to withdraw was disappointing for many, including people in the United States,” says Nuttall. “But so many people are moving on this.”“Now, time is the constraining factor,” he adds. “We need to move very, very fast.”
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Diseases of poverty identified in Alabama county burdened by poor sanitation.
Study finds “shocking” incidence of parasite infections in Lowndes County.
By Brett Walton, Circle of Blue
In the poorest sections of the American South researchers are finding hookworm, dengue fever, and other parasites and viruses that are more commonly associated with developing countries or, in the United States, with the early years of the 20th century.
The latest evidence comes from Lowndes County, Alabama, where Baylor College of Medicine researchers went on an expedition for parasitic worms. They found that two in five people who participated in a recently published health study had intestinal parasites, primarily hookworm. The parasite, once considered contained, is making a comeback in the Black Belt, a region of clay soil that stretches across nearly two dozen counties in central Alabama.
“I was shocked, quite shocked,” Rojelio Mejia, the Baylor College of Medicine researcher who guided the study, told Circle of Blue. “We thought hookworm was eradicated, or at least under control. To find such a high prevalence was concerning.”
Surprised at the results, the research team double- and triple-checked the data to verify accuracy. The peer-reviewed study was published online on September 5 in the American Journal of Tropical Medicine and Hygiene. The diseases, the researchers said, are now less a matter of political borders and more a function of economics and sanitary conditions. In this health equation, the poor suffer.
Though the study’s numbers are startling, the high incidence of parasitic infections is more understandable due to conditions on the ground, Mejia said. The central Alabama climate — warm and humid — is favorable for worms to flourish. Because hookworm is not a sensational disease like Zika or Ebola, it attracts less attention, he said. Anemia and lethargy are common symptoms, rather than birth defects or death. Perhaps most important — and most galling — is that many people live in unsanitary surroundings.
The Alabama Center for Rural Enterprise, a local nonprofit that has conducted surveys to collect data, estimates that half of the homes in Lowndes County have failing septic systems or no sanitary sewage disposal at all. According to U.S. Census Bureau data, more than one-third of households in the county are in poverty.
Many homes in the county are too scattered for a central wastewater facility, and septic systems are often a poor fit for the dense Black Belt soils, which do not drain well enough to filter waste. There are high-tech septic systems on the market, but the cost — around $10,000 to $12,000 — could consume most of a poor household’s annual income. An unknown number of homes instead connect their toilets and sinks to “straight pipes” that send the waste into gullies, creeks, or backyard pits. In these conditions, hookworm and other parasites can thrive.
More than a century ago, in 1909, John D. Rockefeller Sr. gave $1 million to establish the Rockefeller Sanitary Commission, an initiative with the goal of eradicating hookworm in the South. The commission’s work, however, lasted only five years, and hookworm continued to fester in certain areas. Infection rates in high-risk Alabama counties in the 1950s were as high as 60 percent.
Then hookworm assessments largely ceased. Health researchers stopped looking for it. Mejia said the most recent study he could find that included field research was a 1993 graduate student paper that was not published in an academic journal. The study found one to two percent of participants had hookworm in Wilcox County, a Black Belt neighbor of Lowndes.
The Wilcox study and Mejia’s study are difficult to compare. What changed is the method of investigation. Older studies assessed hookworm infections by looking at stool samples beneath a microscope. The level of magnification provided by the lens is not strong enough to detect parasites below a concentration of roughly 12 eggs per gram.
Mejia instead used DNA analysis, which is sensitive to low parasite concentrations, even below one egg per gram. Better equipment means an increase in detection, he said.
Sixty-six people, all African Americans, participated in the study, which included samples of blood, stool, and soil as well as a health questionnaire. Stool samples, taken from 55 of the participants, showed that 23 had a parasite, 19 of which were hookworm.
The number of people in the study was smaller than Mejia had hoped, largely because of the difficulty in recruiting volunteers. There is widespread mistrust within the communities of outside researchers because straight pipes are illegal. Authorities can fine residents, jail them, or even take custody of children living in such conditions.
“People are afraid,” Catherine Flowers, executive director of the Alabama Center for Rural Enterprise, told Circle of Blue. She assisted Mejia, who said that without Flowers the study would probably not have been possible.
Sanitation Failures Widespread in Alabama
No person has done more than Flowers to shine a light on sewage failures in rural Alabama. In November 2012, after reading his New York Times op-ed about tropical diseases spreading among the poor in the southern United States, Flowers sent an email to Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine.
Hotez had estimated that at least 12 million Americans, mostly in the states bordering the Gulf of Mexico, were living with diseases caused by worms and bacteria commonly associated with the warm, humid countries of the tropics: afflictions such as dengue fever, Chagas disease, and parasitic infections that cause seizes.
“They are the forgotten diseases of forgotten people,” Hotez wrote in the piece, published on August 18, 2012.
Flowers, though, would not let the rest of America forget. A week after sending the email, she traveled to Atlanta to meet Hotez, who was attending the annual meeting of the American Society of Tropical Medicine and Hygiene, and explain the problems in Lowndes County. A year earlier she had testified before the United Nations’ independent expert on drinking water and sanitation. More recently, in June, she gave a tour to Sen. Corey Booker, a Democrat from New Jersey, who was traveling in Alabama, Mississippi, and Louisiana to learn about the links between poverty, race, health, and the environment in the South.
Failing septic systems and the use of straight pipes are not confined to Lowndes County, but the extent of the problem is largely unknown. According to Mark Elliot, a University of Alabama researcher, there have been only two rigorous, county-level studies in the United States to establish how many households have failing septic systems or straight pipe discharge. Both studies are more than a decade old.
The first, in 2000, was conducted in Madison County, North Carolina. It found 5.6 percent of homes had straight pipes. The other study, based on data from Bibb County, Alabama, in 2006, found 15 percent of homes used a straight pipe and 35 percent had failing septic systems. In Bibb County alone this discharge corresponds to more than 60,000 gallons of raw sewage per day along with billions of enteric viruses, giardia, and cryptosporidium.
A smaller survey in 2016 of 289 homes without sewer connections in Wilcox County, Alabama, found at least 60 percent with straight pipes, which Elliot called “a staggeringly high number.” Wilcox County is poorer than Bibb County, and poverty is an indicator of straight pipe use. Based on that survey, Elliot estimates that 550,000 gallons of raw sewage in the county enters the Alabama River watershed every day. That figure assumes that each person generates 100 gallons of wastewater a day through showering, toilet flushing, and washing clothes and dishes, which is probably an overestimate of the daily discharge.
Straight pipes are probably more common than thought. An Auburn University study in 2011 estimated that half of Alabama’s Black Belt is unsuitable for septic systems because of poorly drained soils.
Because of the region’s clay soils, wastewater does not readily soak into the ground. Heavy rains can then flush the sewage into creeks and rivers. Elliot tested this by sampling water from Big Prairie Creek, in Hale County, during the 2016 drought and immediately after the first big rain that fall. Water samples downstream of the town of Newbern saw a huge jump in E. coli after the rain — concentrations increased by 1,000 times compared to the drought period. In Newbern, according to best estimates, at least half of homes use a straight pipe.
Elliot does not blame the county health departments, which, he says, have no good options. The arrest, in 1999, of people in Lowndes with illegal sewage disposal provoked backlash and, besides, health departments have no handy solution to offer, he explained. “People really don’t have an option,” he told Circle of Blue.
Mejia and his colleagues hope to eliminate ignorance of the problem. With the results of the initial study now published, Mejia said that he will apply for funding for a larger investigation: a health study of several hundred, maybe even 1,000 people in the county. Then researchers can begin to map areas of greatest need.
Mejia also says there is more work to do on the connections between climate change and disease. Hookworm larvae hibernate in cold temperatures. If winters are warmer, then the window for contracting the parasite, which enters the body through the skin, opens wider.
Flowers, for her part, pins hopes on developing a low-cost wastewater treatment system that suits Black Belt soils.
“We need to deal with the places that haven’t had infrastructure that functions,” she said.
Read Circle of Blue’s award-winning series on America’s spreading septic threat.
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Melting permafrost in the Arctic is unlocking diseases and warping the landscape.
You can find evidence of a changing climate everywhere on Earth. But nowhere are the changes more dramatic than in the Arctic.
Melting permafrost in the Arctic is unlocking diseases and warping the landscape
The consequences of climate change can be weird and apocalyptic.
Updated by Brian Resnick@B_resnick Sep 6, 2017, 10:10am EDT
Photography by Johnny Harris
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The summer sun over Svalbard, Norway, an arctic archipelago that’s rapidly changing due to climate change. Johnny Harris / Vox
You can find evidence of a changing climate everywhere on Earth. But nowhere are the changes more dramatic than in the Arctic.
Our world’s northern polar region is warming twice as fast as the global average. And the consequences are easy to spot. On average, Arctic sea ice extent is shrinking every summer. The Greenland ice sheet is becoming unstable.
But perhaps most disturbing are the changes occurring underground in the permafrost. Permafrost is a layer of frozen soil that covers 25 percent of the Northern Hemisphere. It acts like a giant freezer, keeping microbes, carbon, and soil locked in place.
Now it’s melting. And things are getting weird and creepy: The ground warps, folds, and caves. Roadways built on top of permafrost have becoming wavy roller coasters through the tundra. And long-dormant microbes — some trapped in the ice for tens of thousands of years — are beginning to wake up, releasing equally ancient C02, and could potentially come to infect humans with deadly diseases.
A recent Arctic Council report says that 20 percent of the permafrost near the surface may melt by 2040. Already scientists have noticed permafrost temperatures slowly climbing. “In the 1980s, the temperature of permafrost in Alaska, Russia and other Arctic regions averaged to be almost 18°F,” the U.S. Geological Survey explained in 2015. “Now the average is just over 28°F.”
A 2010 study in Russia found 0.5°C to 2°C of permafrost warming in the past three decades, bringing some locations dangerously close to thawing and pushing the boundary of permafrost regions ever northward. And the depth of the “active layer” — the top layer of permafrost that thaws in the summertime — is growing deeper in the Arctic regions north of Europe, a sign of instability.
When it thaws, a Pandora’s box is unleashed. To better understand the strange changes in the permafrost, I spoke with Robert Max Holmes, an earth systems scientist with the Woods Hole Research Center. When I reached him by phone, he was in Bethel, Alaska, a small outpost town 400 miles west of Anchorage, and had just come back from an eight-day research and teaching expedition in the wilderness.
A week earlier, Holmes and his students had set up temperature sensors in the soil near their encampment. Their first reading was 0.3°C. “It's barely frozen. And we just sort of sat there stunned. You don't know whether to cry or what. Because you're just like: My God, this whole thing is just going to change in a big way.”
Here’s how.
1) Permafrost has been frozen for millennia. Thawing it is a huge disruption.
The icy mountains near Svalbard, Norway, an arctic archipelago that’s rapidly changing due to climate change. Johnny Harris / Vox
The simplest definition of permafrost is ground that has been frozen for at least two years.
But it’s so much more than that. In much of the Arctic, that ground has been frozen for tens of thousands of years. And a huge amount of it is frozen — permafrost rests in 25 percent of all the land area in the Northern Hemisphere.
National Snow and Ice Data Center
The top few inches (up to a few feet) of the permafrost is what’s known as the “active layer.” This topsoil does thaw with yearly seasonal changes, and is home to a thriving ecosystem. So how do scientists know there’s permafrost underneath it?
“We have these things called thaw depth probes, which is basically just a T-bar, a steel rod that's a centimeter in diameter and 1.5 meters or so long,” Holmes says. They poke the ground with it. “It's like pushing a knife through warm butter or something, and then you hit the bottom of the tray, and boom” — there’s your permafrost.
Eventually, if you dig deep enough, the permafrost again thaws due to heat from the Earth’s core.
Permafrost is like the bedrock of the Arctic (you literally need jackhammers to break it apart). But rising air temperatures in the region are chipping away at this bedrock.
“Half the volume of permafrost may be frozen water,” Holmes says. “When that thaws, the water just runs off. The water may head downhill or the water has a lower volume than is ice, so the ground just slumps and kind of falls apart.”
(The New York Times has a great new interactive showing how much permafrost in the Alaska may inevitably melt.)
2) The biggest threat is carbon
Longyearbyen, a settlement in Svalbard, Norway, is home to a seed vault intended to protect plant genetic diversity amid a changing climate. Its Arctic location may not be as secure as once thought due to rising temperatures and melting permafrost. Johnny Harris / Vox
You can think of the Arctic permafrost as a giant kitchen freezer.
If you put organic (carbon-based) matter in your freezer, the food will stay intact. But if the freezer compressor breaks, it will slowly heat up. As it heats up, bacteria begin to eat your food. The bacteria make the food go rotten. And as the bacteria consume the food, they produce carbon dioxide, methane, and other gases and chemicals that smell terrible.
For tens of thousands of years, permafrost has acted like a freezer, keeping 1,400 gigatons (billion tons) of plant matter carbon trapped in the soil. (That’s more than double the amount of carbon currently in the atmosphere.) Some of the plant matter is more recent, and some is from glacial ice ages that radically transformed a lush landscape into a tundra.
“Plants are growing in permafrost regions, and when those plants die, because of the cold temperature, they don't fully decompose, so some of that organic carbon is left behind,” Holmes says. When the permafrost thaws, “it starts to rot, it starts to decompose, and that's what's releasing carbon dioxide and methane,” he says.
This is one reason scientists are so worried about a melting Arctic: When the bacteria turn the carbon in the Arctic into C02 and methane, it accelerates a feedback loop. The more methane and carbon released, the more warming. The more warming ... you get it.
A 2014 study in Environmental Research Letters estimates that thawing permafrost could release around 120 gigatons of carbon into the atmosphere by 2100, resulting in 0.29°C of additional warming (give or take 0.21°C). By 2300, another study in Nature Geoscience concludes, the melting permafrost and its resulting carbon feedback loops could contribute to 1.69°C of warming. (That’s on the high end. It could be as low as 0.13°C of warming.)
But these are just estimates, and they come with a good deal of uncertainty. (There’s debate over how much greenhouse gases can be released out of the Arctic, and how long it would take.) It all depends on how quickly the Arctic warms.
But the logic here is simple: The more warming, the greater the risk of kick-starting this feedback loop. A study published in Nature Climate Change in April predicted that 1.5 million square miles of permafrost would disappear with every additional 1°C of warming.
3) Ancient microbes are waking up
From the air, the arctic still looks pristine and barren. The situation on the ground tells a different story. Johnny Harris / Vox
Last August, an outbreak of anthrax in Siberia sickened 72 people and took the life of a 12-year-old boy. Health officials pinpointed the outbreak to an unusual source.
Abnormally high temperatures had thawed the corpses of long-dead reindeer and other animals. Some of these bodies may have been infected with anthrax, and as Wired explained, the soil in Siberia is normally much too cold to dig deep graves. “The disease from thawing human and animal remains can get into groundwater that people then drink,” Wired reported.
Scientists are worried that as more permafrost thaws, especially in Siberia, there may be more outbreaks of long-dormant anthrax as burial grounds thaw.
That’s because the deep freeze of the permafrost doesn’t just keep carbon from escaping — it keeps microbes intact as well.
Permafrost is the place to preserve bacteria and viruses for hundreds of thousands — if not a million — years, explains Jean-Michel Claverie, a genomics researcher who studies ancient viruses and bacteria. “It is dark, it is cold, and it is also without oxygen. … There is no [ultraviolet] light.” All the bacteria need is a thaw to wake back up. “If you take a yogurt and put it in permafrost [that remains frozen], I’m sure in 10,000 years from now it still will be good to eat,” he said.
Claverie is part of a scientific team that recently determined it’s possible to revive 30,000-year-old viruses trapped in the permafrost. His work is centered on viruses that infect amoebas, not humans. But there’s no reason why a flu virus, smallpox, or some long-lost human infection couldn’t be revived the same way. These microbes are like time travelers — and they could thrive waking up in an age when humans have lost an immune defense against them.
I asked Claverie if there’s an upper limit to how long viruses and (certain types of) bacteria could survive in the permafrost.
“The limit is the limit given by the permafrost,” he explained, meaning he sees no limit. Permafrost is 1,000 meters deep in places, “which make it about a million, 1.5 million year old,” he said.
The danger here, he emphasized, is not from the slow thawing of the permafrost itself. That is, if the permafrost melts, and we leave the land alone, we’re unlikely to come into contact with ancient deadly diseases. The fear is that the thawing will encourage greater excavation in the Arctic. Mining and other excavation projects will become more appealing as the region grows warmer. And these projects can put workers into contact with some very, very old bugs.
The threat is tiny. But it exists. The big lesson is that even viruses thought to be eradicated from Earth — like smallpox — may still lurk frozen, somewhere.
“We could actually catch a disease from a Neanderthal’s remains,” Claverie says. “Which is amazing.”
4) Roadways are warping, foundations are shifting
When the permafrost melts, it literally changes the landscape.
“Oftentimes, permafrost has a great deal of ice in it, so you can get half the volume of that permafrost [that] may be frozen water,” Holmes says. “And so when that thaws, the water just runs off, you know? The water may head downhill or the water has a lower volume than is ice, so the ground just slumps and kind of falls apart.”
In Bethel, Alaska, roadways are literally rippling and warping as the ground beneath them becomes less solid. In other places, the melting permafrost is creating craters and sinkholes. “You see buildings that are kind of slumping into the ground; you see that a lot in the Russian Arctic,” Holmes says. Civil engineers are experimenting with new types of pilings and foundations to help keep Arctic buildings on strong footing.
There is one crater in Siberia so large it’s gotten the nickname "doorway to the underworld.” It’s a kilometer long and up to 100 meters deep. And it’s growing larger every year.
5) When we lose the permafrost, we lose a record of natural history
Johnny Harris / Vox
There are dangers buried in the permafrost. But there are also natural treasures yet to be discovered. The ice preserves all: ancient animal remains and human history in the region. Think of Ötzi, the remarkably preserved 5,000-year-corpse found in the Alps. If he had thawed, what was left of his body would have decomposed, and a window into the world he lived in would have been lost forever.
There may be other Ötzis in the Arctic. Or preserved bits of mammoth DNA yet to be discovered. The melting may make some of these treasures briefly accessible — freed from the ice — but also threatens to quickly destroy them. According to Scientific American, once a specimen is uncovered and thawed, researchers have a year at most to recover it before it completely breaks down.
Are there any benefits to melting permafrost?
“One story I heard of in Bethel is that there are people who are happy that now they can dig a basement,” Holmes says.
There are some benefits of thawing permafrost. For one, farming is now possible in parts of Alaska, as NPR reports. And “So it's not that it's all a bad news story,” Holmes says, “but I'd say the silver lining is pretty thin and pretty small in relationship to the larger-scale negatives.”
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