health_pandemic
'Mosquito-borne pandemic could wipe out 10m people.'
Bill Gates’ latest comments come just months after the Microsoft founder announced details of a major project to tackle the Zika virus.
Features | Health
‘Mosquito-borne pandemic could wipe out 10m people’
By Chukwuma Muanya, Assistant Editor | 03 July 2017 | 4:40 am
Mosquito…A deadly mosquito-borne pandemic poses a greater threat to humankind than global war, billionaire Bill Gates warns.
• New gene editing technique could drive out menace, researchers find
A deadly mosquito-borne pandemic poses a greater threat to humankind than global war, billionaire Bill Gates warns.
In a hard-hitting new documentary, the world’s richest man said a killer bug could wipe out 10 million people without warning.
Footage seen by DailyMailUK Online, set to be aired this Thursday week, shows the philanthropist’s worries towards the danger of disease-carrying mosquitos.
Climate change warming the planet is allowing for mosquitos to spread from their usual habitats, posing a risk to many in the northern hemisphere.
While growing populations in these dense areas and the increasing ease of global travel mean the danger of a pandemic looms large if a virus was to break out – of which the likelihood is growing.
Bill Gates’ latest comments come just months after the Microsoft founder announced details of a major project to tackle the Zika virus. On behalf of the Bill and Melinda Gates Foundation, he donated £14.5 million to find a cure to the most recent threat to humanity.
The tropical virus has the ability to infect more than two billion people in total before it dies out completely, statisticians predict.
The threat is heightened by the lack of resources available to fight a fatal outbreak that could spread around the world at lightning speed, he said.
Speaking on the documentary, titled Mosquito, Mr. Gates said millions are adamant such outbreaks only occur in third-world countries.
He said: “At the top of the list of things I worry about, the risk of a very serious pandemic is quite substantial.
“If you say what could kill 10 million people – yes a war could, but a pandemic is probably even more likely to come and surprise us in that way.”
The documentary, which will be broadcast on the Discovery Channel, looked into the recent Zika virus epidemic that struck more than 70 countries.
Researchers on the programme also warned of the danger of dengue virus, known to be spreading rapidly throughout the world.
The plight of millions of children in Africa, where malaria is rife and kills two people each minute, was also touched upon.
All of the above viruses, and others including the West Nile and Chikungunya, pose a similar threat to humanity, the documentary warns.
Each has the ability to “spread like wildfire” – something that was unthinkable 20 years ago, said Dr. Bart Knols, who has devoted his career to the study of mosquitoes.
Disease-carrying mosquitos kill more than 750,000 people a year, many of whom being children, global figures have shown.
Gates’ comments come as a stark warning, especially seeing as the 61-year-old has previously said bio-terrorism could wipe out 30 million.
Meanwhile, scientists at University of California (UC) Berkeley and UC Riverside, United States (U.S.) have demonstrated a way to edit the genome of disease-carrying mosquitoes that brings us closer to suppressing them on a continental scale.
The study used CRISPR/Cas9 gene-editing technology to insert and spread genes designed to suppress wild insects, while at the same time avoiding the resistance to these efforts that evolution would typically favor. The proof-of-concept study was demonstrated in fruit flies; but the researchers believe this technology could be used in mosquitoes to help fight malaria and other mosquito-borne diseases in the next decade, pending public and regulatory approval.
“What we showed is that, if you disrupt a gene required for fertility in female mosquitoes at multiple sites all at once, it becomes much harder for the population to evolve around that disruption. As a result, you can suppress a much larger population. It’s much the same as combination drug therapy; but for CRISPR-based gene drive,” said John Marshall, the study’s lead author and an assistant professor of biostatistics and epidemiology at the UC Berkeley School of Public Health.
The article was published recently in the journal Nature Scientific Reports.
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Infectious disease collides with changing climate.
In Brazil, a spike in yellow fever cases came after a drought was followed by deluge – and a bumper crop of mosquitoes.
São João Pequeno, Brazil – Two years of drought had been hard on Valdemar Braun and his three grown sons. They lived in the hilly, picturesque Brazilian village of São João Pequeno, and when the rains quit, the coffee would not grow. The farmers were forced to sell some of their cows.
Then at last the showers returned, and 2017 dawned full of promise for the plantations.
Valdemar had given each son two alqueires of land (almost 11 acres). In mid-January, one son helped another clear out forest to plant more coffee.
The portion of forest belonged to Edson Braun, who had recently divorced. He wanted to transfer the land to his ex-wife so that she could provide for their daughters. His brother, Virlei, agreed to help.
Virlei, 30, with pale blue eyes and a handsome face, had his own family to provide for: a wife and toddler son. On the day he went to help his brother, Virlei had already worked on the farm for 14 days straight. Never in his life had he been to a doctor for a health problem.
That day in the forest, relatives believe, a mosquito bit Virlei.
In just 10 days, he would die, doctors desperately trying to lower his fever by packing his abdomen in ice, his mother crying out, “God, don’t take my son. Don’t take my son.”
“Go back home and help raise my child,” Virlei told her. “I’ve already put myself in the hands of God.”
***
Brazil, hit hard by the Zika virus in 2015 and 2016, is once again in the throes of a devastating mosquito-borne disease.
The illness that killed Virlei and at least 263 other Brazilians so far is yellow fever, a virus that can cause victims to vomit blood, suffer liver damage, and even descend into organ failure and coma. In some of Brazil’s forests, the virus recurs every six or seven years.
The current outbreak is the nation’s worst on record; yellow fever deaths in the first four months of 2017 already exceeded all those from 1989 through 2008.
At the epicenter of this epidemic is a group of states that had just recovered from their worst droughts in 80 years. This intersection of drought and disease raises a complex and troubling question for scientists:
Is our changing climate contributing to flare-ups of infectious diseases?
“Yes, this is a factor that is present in our modeling,” says Márcia Chame, a researcher who has been examining the outbreak for the Oswaldo Cruz Foundation in Rio de Janeiro.
But climate alone cannot account for Brazil’s latest bout with yellow fever, according to Chame, coordinator of the foundation’s biodiversity research unit.
Other contributors include the clearing of forests for farms and plantations, an activity that brings humans into areas thick with mosquitoes; the grinding rural poverty that makes insect repellent a luxury for many villagers, and the reluctance of many Brazilians to receive the yellow fever vaccine.
Still, it is clear that the recent climate in the areas most affected by yellow fever — severe drought followed by rainfall — benefits the forest mosquitoes. Their eggs can survive dry weather in a state of suspended animation “for years and years,” according to Michael T. Osterholm, co-author of the new book, “Deadliest Enemy: Our War Against Killer Germs.”
When rains do come, they unleash several years’ worth of mosquito offspring. Whether the current outbreak is linked to climate change “is unclear,” Osterholm cautions. “It wouldn’t surprise me, but I don’t think we can say that.”
So far, yellow fever has been confined to rural, wooded areas, mostly in four states on Brazil’s eastern flank: Minas Gerais, Espírito Santo, São Paulo and Rio de Janeiro. But the virus has already spread much farther than in previous outbreaks, raising an unsettling possibility.
“If this thing takes off in the urban areas of Brazil, we’re in big trouble,” says Osterholm, who serves as director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
Large cities, with their high densities of people and mosquitoes, can fuel an outbreak, just as dry tinder feeds a forest fire.
In late April, Brazilian authorities announced that the latest victim to die had lived just 35 miles from the city of Rio de Janeiro, population 6.3 million.
Experts say it is unlikely the U.S. will see a comparable outbreak of yellow fever, in part because air conditioning and window screens are commonplace, allowing us to keep mosquitoes out of our homes in hot weather. Still, any cases — even those brought here by travelers — could prove unnerving, especially since the currently-approved vaccine is in short supply.
Sanofi Pasteur, the sole manufacturer and supplier of the yellow fever vaccine to the U.S., is experiencing production delays as it moves to a new facility. The vaccine approved for the U.S. is likely to be unavailable from June 2017 until mid-2018, though the company says it has received FDA permission to distribute a different vaccine, unlicensed here, but used in 70 other countries.
The U.S. has not experienced an outbreak of yellow fever in more than a century; the 1905 epidemic in New Orleans that killed more than 430 people was the last. Yet the past 20 years have seen the appearance or reappearance of several other mosquito-borne diseases in this country.
In 1999, it was West Nile virus, which arrived in the U.S. in New York and has since spread through almost the entire country.
In 2001, it was dengue fever, thought to have been eliminated from the U.S. 30 years earlier. Hawaii, Texas and Florida have all reported outbreaks of dengue, a virus that produces flu-like symptoms but can lead to severe illness and death.
Last year, it was the Zika virus making its first appearance in the U.S. in South Florida and Brownsville, Texas, a port city on the Mexican border.
Osterholm notes one parallel between Brazil’s latest bout with yellow fever and the appearance of West Nile virus in New York. “In 1999, when West Nile virus broke in the U.S., lack of rainfall favored the mosquito,” he says.
There is another parallel.
With West Nile, animals fell sick before humans did. Tracey McNamara, then-head pathologist at the Bronx Zoo, noticed crows dropping dead in and around the zoo. Soon afterward, doctors began seeing patients with symptoms resembling encephalitis, including fever, dizziness and fatigue.
In Brazil, monkeys served as sentinels for the latest outbreak of yellow fever. In April 2016 — eight months before any people became sick — a single monkey was found dead on a farm in Montes Claros, about 530 miles north of Rio de Janeiro.
Even in areas where monkeys are plentiful, it is unusual to find one dead. Their bodies generally decompose quickly, or are consumed by scavengers.
In this case, health officials came to Montes Claros to collect the monkey’s remains for testing. Waldney P. Martins, a professor at Universidade Estadual de Montes Claros who studies monkeys, says it took four months to determine the cause of death.
Yellow fever.
José Luis Machado, housekeeper for Fazenda Macacos, the “Farm of Monkeys,” was born just two miles away in the village of Itapina, which lies about 400 miles northeast of Rio de Janeiro.
He has been there so long, he says, that he feels like part of the forest, much like the howler monkeys he used to watch feasting on mango leaves. A group of eight to 10 monkeys were permanent residents. They clambered through the trees. Sometimes their shouts could be heard clear across the Rio Doce, or Sweet River, a mile away.
“This was full of monkeys,” Machado says, staring at a hollow of empty trees. Like many of the Brazilians interviewed for this story, he speaks through an interpreter.
“They were very happy,” he says. “They make the house happy too.”
But on this morning in early April, the house and forest are quiet.
The property’s owner found the first dead monkey on the last day of 2016. Soon after, Machado watched other monkeys fall ill.
“When they were already very sick,” he says, “they would fall down from the tree and die on the (forest) floor.”
About the same time Machado was watching the monkeys die in Itapina, University of Wisconsin-Madison researcher Karen Strier was discovering that a similar tragedy had already played out on a reserve 140 miles to the west.
In mid-January, the professor of anthropology arrived from Wisconsin to find an unnatural quiet in the reserve. In a place she has been coming to for more than 30 years, where she was accustomed to seeing hundreds of howler monkeys, she and her Brazilian colleagues saw fewer than a dozen.
“The forest was really, really different,” she says. “It was actually pretty terrifying.”
Back east in São João Pequeno, Valdemar Braun had also been wondering about the monkey population. Two dozen or so used to come right onto his covered porch to eat juicy guava.
“They have all disappeared,” he says.
Although he cannot remember precisely, he believes the monkeys vanished around the end of last year. Before his son Virlei grew ill and died.
***
The idea that climate and disease are related dates back at least 2,000 years to the Greek physician Hippocrates. He wrote:
“Whoever wishes to investigate medicine properly should proceed thus: in the first place to consider the seasons of the year and what effects each of them produces … Then the winds, the hot and the cold, especially such as are common to all countries, and then such as are peculiar to each locality.”
For some of the most serious diseases, including yellow fever, it is not so much the effect of climate on humans that matters; it is the effect on insects.
“There are some people that argue that global warming’s greatest threat may also be the smallest, and, of course what we’re thinking about are insect-borne diseases,” explains Jonathan Patz, director of the Global Health Institute at the University of Wisconsin-Madison.
“And we all know that insects are cold-blooded, unlike us, and when the temperature changes a little bit, their body temperature changes with it.”
Decades of research has established that Aedes aegypti, a species of mosquito that carries yellow fever, Zika, dengue and chikungunya, thrives in warmer climates.
The mosquitoes are more active, reproduce more frequently and enjoy a longer breeding season, though there's a catch. If the climate becomes too hot and dry it can shorten their lifespan.
In general, warmer temperatures also lead to smaller mosquito offspring which require more blood meals. In other words, they bite more.
Mosquitoes that transmit West Nile virus show a similar sensitivity.
“Every degree above 70 degrees exponentially expands the mosquito’s ability to transmit West Nile virus,” says McNamara, the former Bronx Zoo official, now a professor of pathology at Western University of Health Sciences in Pomona, Calif.
“Forget the cockroach inheriting the Earth. It’s going to be the mosquito.”
Already, warmer temperatures have helped mosquitoes settle into new regions. For example, Aedes albopictus, another of the mosquitoes that carries the viral diseases dengue and chikungunya, “has undergone a dramatic global expansion facilitated by human activities,” according to the European Centre for Disease Prevention and Control.
Found originally in the tropical forests of Southeast Asia, Aedes albopictus, commonly known as the Asian tiger mosquito, has spread into Europe, the Middle East, Africa, and North and South America — largely in the last 30 years. The mosquito, first discovered in the United States in Houston in the mid-1980s, has since spread to 37 states, though not to Wisconsin.
Researchers believe the Asian tiger mosquito’s rapid advance has been fueled by international transport of old tires and bamboo, objects that retain water, making them ideal places for mosquitoes to lay eggs.
Once carried overseas, however, the mosquitoes are finding the warming climate to their liking. In a 2013 paper in the journal PLOS ONE, researchers said the Asian tiger mosquito “is poised to significantly expand its range in the northeastern United States in the next few decades primarily due to warming winter temperatures.”
Where the mosquitoes migrate, disease often follows.
In the summer of 2007, Europe experienced its first epidemic of chikungunya in northeastern Italy. In the years since, France and Croatia have experienced their own outbreaks. The disease, which causes fever and severe joint pain, had been found mostly in Africa, Asia and India.
In December 2013, chikungunya was detected for the first time in the Americas, on the Caribbean island of Saint Martin. Since then, the disease has been found in 45 countries or territories in the Americas, though it has rarely appeared in the U.S., according to the U.S. Centers for Disease Control and Prevention.
And mosquitoes aren’t the only bearers of disease that flourish in warmer climates.
Sand flies, which transmit the parasite that causes leishmaniasis, a skin disease, are also more active and take more blood meals in warmer temperatures.
Blacklegged ticks have prospered in the heat, aiding the northward expansion of Lyme Disease. Lyme cases in Canada have risen more than five-fold since 2009; Lyme cases in Wisconsin have doubled since 2000.
“The growing season’s longer. It’s great for ticks and not so great for human health, because if those ticks have another couple of weeks in which to find a host, then many more of them are likely to survive,” says Richard Ostfeld, senior disease ecologist at the Cary Institute of Ecosystem Studies and director of a study aimed at preventing tick-borne diseases.
In a 2005 paper in The New England Journal of Medicine, Harvard University tropical health expert Paul R. Epstein offered one example of how a change in climate can ripple through an ecosystem. Epstein described the arrival of a new disease with flu-like symptoms, carried by rodents and passed to humans:
“Six years of drought in the Southwest apparently reduced the populations of predators, and early heavy rainfall in 1993 produced a bounty of pinon nuts and grasshoppers for rodents to eat. The resulting legion of white-footed mice heralded the appearance of hantavirus in the Americas.”
Few scientists, if any, attribute the spread of these diseases to climate change alone.
Studies suggest that other likely factors include global reductions in pesticide use and massive increases in waste plastics, such as bags, suitable for breeding by mosquitoes. In a larger sense, the growth and spread of the world’s population into rural areas is undoubtedly bringing more humans onto the turf of mosquitoes, ticks and other parasites and insects.
In Brazil, some point to another possible culprit for the current bout of yellow fever, though the theory is controversial.
“(It is) due to the environmental disaster which happened in Mariana,” says Antônio Thadeu Tardin Giuberti, the health secretary for the municipality of Colatina.
He refers to the Nov. 5, 2015, dam failure at a mine in Mariana, 250 miles north of Rio de Janeiro. When the dam failed, a torrent of iron ore waste flooded the countryside, killing 19 people and contaminating the Doce River, the same river that flows past the villages where José Luis Machado watched the monkeys die and where Valdemar Braun lost his son.
While Giuberti also attributes the severe outbreak to low vaccination rates and the droughts, he says that the mosquito population rose sharply after the Mariana disaster. He believes the flood of waste material from the dam killed off frogs, the mosquito’s main predator.
At the Oswaldo Cruz Foundation, Márcia Chame says "there is no scientific data that links the disaster with yellow fever.”
On one point, however, she and Giuberti agree.
The outbreak turned a critical corner when the virus spread from the state of Minas Gerais, where it was regularly found, to the neighboring state of Espírito Santo, where it was not.
With no previous experience of yellow fever, many in Espírito Santo remained unvaccinated. The state began vaccinating rural residents on Jan. 23, a week after learning of its first human case, according to Giuberti.
For six days straight, health care teams worked furiously, vaccinating an average of 15,000 people a day.
Though rarer than it once was, yellow fever retains a hellish reputation among doctors.
“This disease has struck fear in the hearts of man ever since it was discovered. It’s so severe, so lethal, such a horrible death,” says Thomas P. Monath, who has been studying yellow fever since 1968, and now serves as chief scientific officer for BioProtection Systems Corp., an Iowa-based company involved in vaccine work.
Named for the sickly yellow color that permeates a patient’s skin and eyes, the virus likely emerged about 5,000 years ago, when it was transmitted from primates to humans in Central or East Africa.
In the 1600s, the disease and its most common carrier, Aedes aegypti, came to the Americas aboard slave ships. The U.S. experienced at least half a dozen epidemics, including one in Philadelphia in 1793 when the city was still the nation’s capital. Nearly 5,000 people died in three months, and more than one-third of Philadelphia’s 50,000 residents fled the city.
During construction of the Panama Canal in the early 1900s, yellow fever and malaria killed thousands of workers, prompting U.S. authorities to launch a campaign to improve sanitation and water, and to eliminate mosquito breeding sites.
Only in 1937 was a yellow fever vaccine developed by the South African biologist Max Theiler. Since then, vaccinations have helped rid many countries of yellow fever, though outbreaks continue to flare up in South America and Africa.
In Brazil, the outbreaks have not reached the cities in decades, remaining instead in the sylvatic, or jungle, cycle. Mosquitoes in the jungle pick up the virus from monkeys and pass it to other monkeys or humans working nearby.
In late December 2016, Angola declared the end of a year-long yellow fever epidemic that had spread to its African neighbor the Democratic Republic of Congo, causing 400 deaths in the two countries.
A week after Angola sounded the all-clear, Brazil’s human outbreak began in the state of Minas Gerais.
On Dec. 30, the first two yellow fever patients showed up at the bustling Santa Rosália Hospital in Teófilo Otoni, about 450 miles north of Rio de Janeiro.
The patients, both from the nearby town of Itambacuri, entered in critical condition, “vomiting blood,” says Rodrigo Lobo, a doctor of emergency medicine at Santa Rosália. “There was blood in their feces. The whites of their eyes went yellow and their urine looked darker.”
They were initially diagnosed with dengue fever, but the 39-year-old doctor wasn’t so sure. Lobo remembered hearing that monkeys had been found dead in Itambacuri several months prior; the cause was determined to be yellow fever. So he diagnosed the patients with yellow fever, and sent blood samples to be tested.
By the time the tests confirming his diagnosis came back more than two weeks later, both patients were long dead.
On New Year’s Day, sick people began arriving from other nearby towns and villages. Most were in the third and final stage of the disease. They had yellow eyes and skin, and were bleeding from their mouths.
“The walking dead,” Lobo called them.
The doctor worked around the clock, though there was little he could do. Every patient that first week died — 16 in all.
“In the beginning, I used to have nightmares,” Lobo says. “The evolution of the sickness is so quick. With all of the resources we were applying, to see young people dying was not easy. It was very hard to see people in the last stage bleeding, and you cannot do anything to stop the bleeding. It was horrifying.”
To make matters worse, doctors at Santa Rosália, which serves more than 60 municipalities, had not been paid for eight months due to a decrease in funding for public health. By the time of the outbreak, many employees had quit to pursue other jobs, forcing the hospital to cope with a scarcity of workers and even shortages of basic materials such as gauze and certain medicines.
Lobo was among the few who stayed. Another was Ricardo Vitorio, a 35-year-old kidney specialist who remembers working seven days a week, getting what little sleep he could at the hospital.
At first, few outside the hospital knew of the outbreak. News filtered out in an unusual way. Before any official announcements had been made, Lobo wrote to friends on the instant messaging service WhatsApp, telling them not to fish or hunt in the bush until the cause of the outbreak had been determined.
The message reached a local reporter, 38-year-old Elvis Passos, who asked Lobo for permission to publish it. On Jan. 6, Passos shared the doctor’s warning with 34,000 followers on his Facebook news page.
According to the World Health Organization, Brazil reported the first cases that same day. But in an email interview, Passos says there was no public announcement of the outbreak until two days after his Facebook post.
Passos would later be praised by some for alerting the public, and criticized by others for causing panic.
In the weeks that followed, Vitorio says, he treated about 120 yellow fever patients, among them two brothers, José Ramos and Vando Ramos Ferreira, 46 and 39. The brothers were bean and coffee farmers from Novo Cruzeiro, a town about 70 miles northwest of the hospital.
In early January, José was washing clothes in a river when he saw a dead monkey.
A few days later, he had a headache and fever. Soon he was vomiting and had no appetite.
By the time José was taken to a small local hospital, he could not stand on his own. Two days later, on Jan. 11, he was transferred from the first hospital to Santa Rosália. His brother, Vando, a father of five, arrived at Santa Rosália more than a week later.
At first, Vando appeared relatively healthy. He was placed in a regular room rather than one reserved for emergencies.
José, however, grew worse. He remembers thinking he would die, and asking God to feel pity for him.
Vitorio thought there was a 98% chance José would not survive.
“There is no drug to kill the virus,” the doctor says. “There are medicines that will give the organs conditions for recovery.”
Yellow fever primarily afflicts the liver, kidney, lymph nodes and spleen. The most critical patients at Santa Rosália were placed on dialysis. Some already had weakened livers from alcohol use, leaving doctors few options.
“How can you transplant livers for 50 or 60 people at once?” Lobo says.
Despite the dire prediction, José improved. After 32 days in the hospital, he went home.
Now it was Vando who grew ill, so ill he had to be placed on dialysis. On April 14, his hospital stay passed the three-month mark. He continues on dialysis and may remain so for the rest of his life, Vitorio says.
His likelihood of death had been 99%, Vitorio adds, predicting the two brothers may one day be the subject of medical papers. “Why they are still alive, this is going to be studied.”
The doctor’s face tightens as he discusses the disease’s spread, made worse in his view by poverty and lack of information. Though yellow fever is endemic in the state, Vitorio says, the vaccination rate was poor. State health records show fewer than half of Minas Gerais’ 20 million residents had received the yellow fever vaccine prior to the outbreak.
“For the influenza vaccine, there is a TV campaign,” he says, “but for the yellow fever vaccine they had posters. They never had a campaign (on television).”
Vitorio believes people fear the yellow fever vaccine, or think it unimportant.
Vaccination is mandatory for children born in 2002 or later, and many mothers get vaccinated when they bring in their children. Vaccination is far less common among men. The vast majority of yellow fever patients at Santa Rosália were men, usually age 50 or under. Many worked in the forest where they frequently came in contact with mosquitoes.
“There is a masculine attitude,” says Lobo, the doctor of emergency medicine. “ ‘I’m a Superman. I’m strong. I’m not going to get this.’ ”
“What happened here was a catastrophe,” Vitorio says. “A lot of young adults died because of a sickness that could have been avoided … A lot of children, they remain without family. The children were required to get the vaccine. The parents weren’t.”
Within a few weeks, the virus had spread to the state of Espírito Santo, where the population was even less prepared.
***
In São João Pequeno, 3-year-old Vitor Hugo Braun plays with LEGOs on the floor, while his grandparents describe what happened to his father, Virlei Braun.
“It was too quick,” Valdemar says, staring into the distance.
Virlei, who had never been vaccinated, fell ill almost three weeks after the first yellow fever patients had arrived at Santa Rosália. After lunch on a Sunday, he became feverish. The veins in his forehead bulged, his mother, Cecilia Braun, remembers.
The following day he went to the hospital in Colatina. Doctors thought he might have dengue or leptospirosis, a bacterial disease that can lead to kidney damage.
“Nobody knew what it was,” Valdemar says. “They left him for two days in bed. They were giving him medicines and putting tubes into him without knowing what it was.”
Virlei remained in the hospital on Jan. 27, his son’s third birthday.
“Mom,” he said, “bring my son. I want to give him a kiss on his birthday.”
Since the hospital would not allow children to visit, Virlei tried to rise from bed to go see Vitor Hugo at his school. But as Cecilia Braun helped her son struggle to his feet, Virlei shuddered in pain.
“Mom,” he said. “I cannot.”
He slumped back onto the bed. Two days later, doctors realized he was bleeding internally. They still had not diagnosed the disease.
Virlei heard his mother crying, and called on her to be strong.
He died a few days later on Feb. 1. Only after death was he diagnosed with yellow fever, his parents say.
They brought his body home for the funeral and tried to keep Vitor Hugo from seeing it. But the little boy peeked in the room where the body lay.
He kept asking his grandmother: “Is he sleeping? Is he sleeping? Is he sleeping?”
A week or two after Virlei’s death, the virus arrived in the state of Rio de Janeiro, in a village known as Córrego da Luz, “River of Light.”
Some of the locals believe the disease was brought by a tourist from the state of Minas Gerais. They had not heard of any sick monkeys.
However, researchers from the Oswaldo Cruz Foundation came to investigate the outbreak and found a dozen dead monkeys in the forests around the village, Márcia Chame says.
The first villager to be sickened was an energetic jokester named Watila Santos, who was 38 and married. Watila worked in construction, drove trucks and grew bananas and oranges. He and his wife had just moved to the village in January to live with relatives in a small cluster of houses built on a cleared patch of forest.
A group of men, including Watila, had gone into the jungle around the end of January to check on an area where oranges had been planted. Soon afterward Watila became sick with a fever and headache. When he went into the local hospital, “they said, ‘This is a simple virus. Go back home,’ ” his brother, Roberto dos Santos, says.
Watila spent four days sick at home. On the fifth day, his vomit was black.
“On Friday he was falling apart. When he went to the hospital and was taken to the infectologist area,” Roberto says, “it looked like his body had been painted yellow.”
It was now early in February. During a visit from his mother, Watila told her, “I’m not going to leave this hospital.”
About this time, a few others from Córrego da Luz fell ill.
Alessandro Valença Couto, a 38-year-old social services worker, who’d never had a serious illness before, felt at first like he had a cold. But on Feb. 5, after two days of illness, he began to vomit. Like others, he had not received the yellow fever vaccine and never wore insect repellent.
“Here, it has always been a lot of mosquitoes,” he says, explaining why many don’t bother with repellent.
Although Alessandro also went to the hospital, doctors said his illness might be meningitis or leptospirosis. He was then transferred to a bigger hospital, the State Infectology Institute in São Sebastião. Doctors diagnosed him with yellow fever and kept him hydrated through an IV line. He would spend 10 to 12 days in the hospital.
“It was horrible,” recalls Alessandro’s wife, Luciana Moreira. “I felt afraid of losing him.”
As she worried, another villager lost his fight. On Feb. 11, at 3 in the morning, Watila Santos died. Although he had always appeared healthy, relatives said he had other medical problems that may have left him unable to fight off the yellow fever virus. Within days of his death, some 30,000 people were vaccinated in the nearby city of Casimiro de Abreu.
Alessandro proved more fortunate than Watila. A little less than a week after his neighbor’s death, Alessandro went home to his wife and their 3-year-old son, Davi Luiz. He still suffers from pain in his stomach and worries that he may have permanent damage. But the family is glad he survived.
In mid-April, Luciana Moreira was pregnant. The couple plans to name their new son Bernardo.
Cecilia Braun says that her son, Virlei, had a favorite Bible passage, which was read at his funeral: John 16:32.
A time is coming and in fact has come when you will be scattered, each to your own home. You will leave me all alone. Yet I am not alone, for my father is with me.
She agonizes over her son’s death, thinking maybe they should have taken him to a better hospital the instant his illness appeared serious.
“That’s where we have failed,” Valdemar Braun says quietly.
The sun is beginning to set over their little village. It’s the time of day when Virlei used to return from his farm work to pick up Vitor Hugo. There is a brief silence.
“Now, I want to ask you a question,” says Cecilia Braun, looking as if she is straining to understand something beyond her grasp.
“Do you think that just a little mosquito can take the life of such a big, strong man?”
How we reported this story
This story is based on extensive interviews in Brazil with yellow fever patients, relatives of those who died of the disease, doctors, researchers and health officials. Translation was provided by Nanda Scarambone, a freelance researcher. Other interviews were conducted by phone and email before and after the trip. Some scenes and conversations have been reported based on the recollections of those who were present. The story also draws on interviews with dozens of scientists, vaccination records from the state of Minas Gerais in Brazil's southeast region and more than 80 medical and scientific papers.
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Rising Waters Threaten China’s Rising Cities
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In the Pearl River Delta, breakneck development is colliding with the effects of climate change.
By MICHAEL KIMMELMAN, Photographs by JOSH HANER
GUANGZHOU, China — The rains brought torrents, pouring into basements and malls, the water swiftly rising a foot and a half.
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The city of Dongguan, a manufacturing center here in the world’s most dynamic industrial region, was hit especially hard by the downpour in May 2014. More than 100 factories and shops were inundated. Water climbed knee-high in 20 minutes, wiping out inventory for dozens of businesses.
Next door in Guangzhou, an ancient, mammoth port city of 13 million, helicopters and a fleet of 80 boats had to be sent to rescue trapped residents. Tens of thousands lost their homes, and 53 square miles of nearby farmland were ruined. The cost of repairs topped $100 million.
Chen Rongbo, who lived in the city, saw the flood coming. He tried to scramble to safety on the second floor of his house, carrying his 6-year-old granddaughter. He slipped. The flood swept both of them away.
Flooding has been a plague for centuries in southern China’s Pearl River Delta. So even the rains that May, the worst in the area in years, soon drifted from the headlines. People complained and made jokes on social media about wading through streets that had become canals and riding on half-submerged buses through lakes that used to be streets. But there was no official hand-wringing about what caused the floods or how climate change might bring more extreme storms and make the problems worse.
A generation ago, this was mostly farmland. Three vital rivers leading to the South China Sea, along with a spider’s web of crisscrossing tributaries, made the low-lying delta a fertile plain, famous for rice. Guangzhou, formerly Canton, had more than a million people, but by the 1980s, China set out to transform the whole region, capitalizing on its proximity to water, the energy of its people, and the money and port infrastructure of neighboring Hong Kong.
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In 1988, the built-up areas in Guangzhou were surrounded by rural agricultural regions and waterways.
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By 2006, many of the built-up areas had merged.
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Rushing to catch up after decades of stagnation, China built a gargantuan collection of cities the size of nations with barely a pause to consider their toll on the environment, much less the future impact of global warming. Today, the region is a goliath of industry with a population exceeding 42 million.
But while prosperity reshaped the social and cultural geography of the delta, it didn’t fundamentally alter the topography. Here, as elsewhere, breakneck development comes up against the growing threat of climate change. Economically, Guangzhou now has more to lose from climate change than any other city on the planet, according to a World Bank report. Nearby Shenzhen, another booming metropolis, ranked 10th on that World Bank list, which measured risk as a percentage of gross domestic product.
While it is difficult to attribute any single storm or heat wave to climate change, researchers say there is abundant evidence that the effects of climate change can already be seen — in higher water levels, increasing temperatures and ever-more severe storms.
And climate change not only poses a menace to those who live and work here, or to the massive concentration of wealth and investment. It is also a threat to a world that has grown dependent on everything produced in the area’s factories.
Some of the liveliest parts of Guangzhou are near the water, and are being flooded more and more often.
The rising South China Sea and the overstressed Pearl River network lie just a meter or so below much of this new multitrillion-dollar development — and they are poised to drown decades of progress, scrambling global supply chains and raising prices on a world of goods like smartphones, T-shirts, biopharmaceuticals and even the tiny springs inside your ballpoint pens.
As always, climate change works like an opportunistic pathogen, worsening existing woes, not acting alone. This can make it hard to pin down, easy to dismiss. Notoriously, China today is crippled by air pollution, linked to local emissions from coal-fired power plants, steel factories and cars. New research shows that rising temperatures and stagnant air resulting from climate change — caused largely by worldwide emissions of carbon dioxide — are exacerbating China’s smog crisis, which has contributed to millions of premature deaths.
The Chinese government has become an outspoken voice on climate change. President Xi Jinping, who is meeting this week with President Trump, has urged the signatories of the 2015 Paris climate accord to follow through on their pledge, while state-run Chinese media has criticized the Trump administration for “brazenly shirking its responsibility on climate change.”
China is now the world leader in domestic investment in renewable energy, and over the past decade the central authorities in Beijing have made environmental performance a higher priority for civil servants. But stronger mandates haven’t yet overcome the pace of expansion, a decentralized fiscal system, lax enforcement and a culture that frequently pits growth against green. The country continues to consume as much coal as the rest of the world combined, and to increase its steel capacity.
Villagers in their flooded home after rainstorms pounded Guangdong Province in May 2014.
Here in Guangdong Province, all the new cars, the concrete and the belching factories spike temperatures, endangering sick and elderly people, creating urban heat islands and incubating pandemics like dengue fever, an outbreak of which slammed Guangzhou in 2014, afflicting 47,000 people.
On top of this are the floods and tidal surges, worsened by a mix of ever-more severe storms and land sinking under the sheer weight of development — amplifying the impact of rising waters. The flooding and surges overwhelm hastily planned, often shoddily constructed buildings and neighborhoods with overstressed sewage systems in poorly conceived areas of urban sprawl. The Chinese authorities like to show off the region’s shiny new office towers and airports, which generate cash and enhance the country’s prestige. Fixing costly sewers that no one sees is not a high priority.
In the meantime, the costs of inaction rise like the tides and temperatures.
The destruction of Shenzhen’s wetlands in recent decades poses one of the area’s biggest climate challenges.
Natural Defenses Paved Over
One afternoon, I met Cai Yanfeng at a Starbucks in Shenzhen. The Starbucks occupies a ground-floor corner in a factory complex where her parents used to work, now converted into high-end rental lofts and art galleries. Fashionable young Chinese sipped Frappuccinos and stared at smartphones.
Shenzhen was still a sleepy fishing village of some 35,000 during the late 1970s when Chinese authorities declared it a Special Economic Zone, bringing in huge investments and waves of migrants from the countryside who have helped make what today is a metropolis of 11 million. Ms. Cai arrived during the early 1980s as a toddler with her parents. Now trained as an urban designer, she has seen the city’s evolution and, at 36, is a relative old-timer.
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She was recalling her childhood, when she would cross the street up the block from where the Starbucks is now to play in the mangrove swamps hugging the bay. Ms. Cai gestured out the window, as if pointing at something, although the world she was conjuring up had long ago vanished. Today, the street she used to cross is the size of an American Interstate. Where the mangroves started, not far from the Starbucks, a hospital campus flanks a shopping mall. The mangroves were ripped out and bulldozed, replaced by landfill, and smothered by acres of concrete, asphalt, office towers, high-rise apartments and industrial development.
“It started with amusement parks along the beach,” Ms. Cai remembered. “Then the city built another big road near the sea, with the area filled in between with residential blocks. Things sped up after that.”
The destruction of the wetlands where Ms. Cai once played is now one of the region’s biggest climate challenges. Mangroves provide a natural buffer from the sea, shielding the coastline, reducing the impact of waves and rising water, filtering out salt that can infiltrate freshwater reserves, absorbing exceptional quantities of carbon and lowering ambient temperatures. But about 70 percent of the mangrove forests in Shenzhen are gone. And their disappearance is accelerating: 2,100 acres paved over between 1979 and 1985; 6,700 more acres during the next decade; thousands and thousands more since.
Recently, Chinese officials announced plans to add yet another 21 square miles of landfill along Shenzhen’s coast. The problem isn’t just the destruction of mangroves. Landfill is notoriously vulnerable to rising waters. When Hurricane Sandy socked Lower Manhattan in 2012, it swamped streets built on landfill, peaking where the island’s long-obscured natural shore had once been. In the end, nature always finds its level. Along the Huishen Highway in Shenzhen, rising seawater recently eroded a stretch of landfill three football fields long, leaving a shamble of asphalt and concrete. When a typhoon pounded the delta in 2008, a third of the sea wall in Zhuhai crumbled, letting water reach the city.
About 70 percent of the mangrove forests in Shenzhen have been cleared.
By contrast, Zhuhai’s nature preserve, where the mangroves had not been cut down, absorbed the brunt of the water and survived.
In Shenzhen, I came across Xiyong Beach, which local fishermen say has been shrinking, gradually swallowed up by rising waters that experts here link to climate change. Chen Tegu, a professor in Guangzhou with the State Oceanic Administration, has been taking measurements since the mid-1980s, watching coastline disappear. Mr. Chen ticked off statistics about temperatures, storms and drought, predicting that the South China Sea could rise almost as much as a foot and a half by the end of this century.
That increase, exacerbated by the sinking of the land, will mean more salt water infiltrating the delta, which, combined with drought, threatens drinking water. A drought several years ago caused water shortages for millions of delta residents, and five major saltwater incursions from the South China Sea have hit the region in the past 20 years alone. These incursions corrupt not only the water that people drink but also the water used by factories, corroding equipment and raising production costs, with ripple effects all along the distribution network. Local agricultural yields have been hurt as well. China has been building water treatment plants, but the pace hasn’t kept up with the threat.
I asked Ms. Cai whether she thought people in Shenzhen worried much about climate change. “Some NGOs talk about it,” she said, “but people here still focus on the economic side of things, on jobs and G.D.P. They care about whether we are a first-tier city yet. Are we beating Guangzhou?”
Liang Bo, who works for the Shenzhen Mangrove Wetlands and Conservation Foundation, agrees. I walked with her through a waterfront park that’s more or less where Ms. Cai once played in the mangroves. Along the shore, garbage washed up on the rocks from the murky, gray water in the bay.
“It’s worse at low tide,” Ms. Liang said. “You really see how filthy it has become.” Because of all the landfill and new development, she said, water no longer flows in and out of the bay as it once did. So garbage gets trapped, stagnation gets worse, fish are killed off. That scenario is repeated throughout the delta, where small rivers and tributaries have been filled in and paved over to make way for new highways, office parks and housing developments, adding to the strains on an already inadequate system of drains and sewers.
“The sea, the wetlands and mangroves used to be part of people’s lives here,” Ms. Liang pointed out. “But most of the people who live here now weren’t around when the mangroves were still here. They see this park, which makes us more vulnerable to rising seas and typhoons, as they do all the tall buildings and highways. They equate it with progress.”
Climate change is worsening existing problems in China, like the effects of air pollution linked to car emissions.
The Trillion-Dollar Question
“Air pollution is a direct challenge to people, it’s right in their face,” said Ma Jun, founder and director of the citizen-led Institute of Public and Environmental Affairs in Beijing. “It’s about the food they put on their table for their children. So they’ve made noise, and things have changed in terms of air pollution policy by Chinese authorities. On the other hand, climate change is happening at a different speed. Sea level rise is not something you easily notice.”
This is the challenge everywhere. Storms, like hot days, happen all the time — and they have always happened. So people don’t automatically chalk them up to climate change. Climate change is like the tortoise. Development is the hare. “The problem isn’t unique to China,” Mr. Ma said. “There is no obvious, short-term solution to climate change problems, no clear strategy everybody agrees is what needs to happen to offset climate change. And there’s no certainty about how to pay for what needs to be done. So there’s reluctance to address the issue. What’s the business model?”
That’s a trillion-dollar question, according to the World Bank, which projected the potential cost of damage to coastal cities worldwide from rising seas to be somewhere near that figure. It estimates that China is already losing 1.4 percent of its annual G.D.P. to climate change. Last spring, residents in Guangzhou woke again to flooded streets after a furious downpour swept across the delta and drowned entire neighborhoods of the city. Local news media, once more, said that there had been nothing like it in years. And as usual, Chinese social media sites buzzed with posts of people trapped in flooded cars. One man, named Pang, became an overnight celebrity for catching a fish with his umbrella, then going home and making soup with the head and tail. “It was fresh and tender,” he told The Guangzhou Daily.
Canals and waterways that once helped to drain cities like Guangzhou have been paved over. Library of Congress, via Getty Images
Rains brutalized many other cities throughout southern China last year: More than 160 people were killed by drowning and landslides, dozens went missing, 73,000 homes collapsed and more than a million acres of farmland were destroyed. The death tolls from floods across China have actually been trending downward, thanks to improved emergency relief efforts. But the damage is increasingly felt in urban areas, where overdevelopment continues to outpace the country’s appetite for climate change adaptation and natural disaster preparedness.
That’s partly because canals and waterways that once helped to drain cities like Guangzhou naturally have been filled in and paved over with concrete and asphalt. Especially in older, underserved areas, the infrastructure replacing the canals is shoddy. While Guangdong now claims more billionaires than any other province in the country, it is also home to millions of low-wage workers and migrants from the countryside who have settled in cheaper, poorly maintained neighborhoods, the crumbling legacy of humongous Socialist-era housing developments.
Zhou Jianyun, an architect and professor who moved to Guangzhou as a student in the early 1980s, took me one day to see some of the older parts of the city most prone to flooding. We toured the area around what used to be the ancient city gates. Streets once lined with handsome covered pedestrian arcades from the 1930s have been widened into boulevards to make more room for cars. Farther west, older neighborhoods spill toward the Pearl River. In many ways, these neighborhoods, like Guangzhou’s ancient villages — crowded, labyrinthine vestiges of old Canton now dwarfed by giant new shopping malls and housing complexes — are the liveliest parts of the city. But they are also more and more frequently underwater because they are near the river, inadequately protected and ill served by the outdated sewage system.
A waterfront park in Guangzhou.
To the east, an immense, modern district called Tianhe has risen from next to nothing in 30-odd years, its offices and apartment blocks now overshadowed by the super-tall skyscrapers of Guangzhou’s Zhujiang New Town, with its opera house by Zaha Hadid and its signature Canton Tower. The picture-postcard image of New Town can bring to mind American downtowns from the late 20th century — cities like Atlanta or Phoenix, only glossier and on a vast scale. Advertised as more environmentally conscious than older parts of the city, with better flood protections, New Town is still a sprawling development conceived for cars and glass towers, with a carbon-heavy diet still dependent on highways and air-conditioning.
“The cities we now have are partly based on what we saw in American movies — on the dream of big malls, airports, highways and tall buildings,” Mr. Zhou said. “I belong to the generation that witnessed the biggest change. We had been almost like North Korea, closed off. Suddenly we could see American movies.”
“This became our idea of progress,” he added. “Only we wanted to do everything bigger, because we thought that is what it meant to be modern. The actual needs of the real city are ignored.”
“In many ways, we are still living a dream,” he said.
Guangzhou’s International Finance Center skyscraper.
An Exodus and an Opportunity
Clearly, the region’s future depends on whether, and how fast, Chinese officials redefine that concept of progress.
“China’s feelings about modernization keep changing,” said Zhou Ming, an urban planner in Shenzhen who expressed some optimism for the future. We met one afternoon in the glittery hotel lobby at the top of KK100, a 1,400-foot skyscraper with a panoramic view that takes in Hong Kong.
“Before the opening to the outside world, people didn’t have food to eat,” he said. “So they focused on jobs and basic needs. Now wages are going up for workers, people are concerned about air pollution and they are starting to value traditional culture again, meaning neighborhoods that are human-scale and not just a bunch of skyscrapers. That’s on top of pressure from international businesses whose employees care about environmental and climate issues and can decide whether they want to do business here.”
Not incidentally, some factories have been leaving Guangdong. Rising wages and threats of stiffer pollution standards have prompted less scrupulous manufacturers to move their businesses to countries like Vietnam and Cambodia, where regulations are weaker. In turn, those countries are repeating mistakes, related to climate change preparedness, that China is paying for now.
But this exodus, seeking short-term profits, has also created an opportunity for China. Planners and environmentalists here talk about a chance to rebrand Guangdong Province as a global leader in green, cutting-edge industrial technology and urbanism — to go beyond token green skyscrapers and really get ahead of climate change. To make China the leading green global superpower.
The opportunity has increased as the Trump administration has retreated on the environment, attacking clean energy, promoting outmoded coal, seeking to undo longstanding federal protections even for drinking water and air. China recently announced that it wanted to create a national market for greenhouse gas quotas, suggesting that it was increasingly persuaded by the financial argument for climate adaptation. A recent report by Bloomberg Philanthropies made just that case, citing billions of dollars in climate-related engineering and construction opportunities.
The neighborhood of Tangxia in Guangzhou.
Prosperity will ultimately belong to cities and nations around the world that find ways to capitalize on strategies of resilience against the inevitable impact of climate change. Those cities will retool themselves for new technologies and global businesses whose employees, reflecting a growing worldwide generational shift, want to walk, ride bikes and take mass transit.
China has demonstrated that it can be nimble and ingenious. Since 1997, Guangzhou has opened an entire new metro system with scores of stations, covering hundreds of miles; Shenzhen has done the same in only a dozen years. New York has barely managed to construct four subway stations in half a century.
But little of this infrastructure in China was conceived in anticipation of extreme conditions and climate change. Rising waters repeatedly reduced train traffic in the delta to a crawl last year, halting ferry service on the Pearl River and turning several of the new subway stations into swimming holes.
“What climate change says is that if you want to maintain the city as a good place to live and work for everyone, business as usual won’t do,” said Robert J. Nicholls, a professor of coastal engineering at the University of Southampton in England. He helped write the World Bank report that warned of the fiscal impact of climate change on the Pearl River Delta. “Disasters will become more likely. And the last thing the Chinese want is a Katrina event,” he added, referring to the hurricane that devastated New Orleans in 2005.
Flooding is not an insurmountable hurdle, he noted. The Chinese can build smarter cities — healthier, safer, more equitable and humane ones, with restored waterways and waterfronts, flood-proof buildings, wide-reaching air-pollution controls, earlier warning systems, levees that double as parks, retention ponds that provide recreation, neighborhoods less dependent on cars.
“The challenge for the Chinese, as it is for so many others,” he said, “is taking the long view.”
Which shouldn’t really be so hard, considering the recent past. The government estimated regional losses from last summer’s floods alone at $10 billion. For all of 2016, rainfall in China was 16 percent above average.
That was the highest level in recorded history.
Shenzhen was transformed in a few decades from a small fishing village into a city of millions.
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Collapse of Aztec society linked to catastrophic salmonella outbreak.
DNA of 500-year-old bacteria is first direct evidence of an epidemic — one of humanity's deadliest — that occurred after Spanish conquest.
DNA of 500-year-old bacteria is first direct evidence of an epidemic — one of humanity's deadliest — that occurred after Spanish conquest.
Ewen Callaway
16 February 2017
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Bettmann/Getty
The Spanish invasion of Mexico, depicted in a nineteenth-century illustration, was followed by a series of epidemics of unknown cause.
One of the worst epidemics in human history, a sixteenth-century pestilence that devastated Mexico’s native population, may have been caused by a deadly form of salmonella from Europe, a pair of studies suggest.
In one study, researchers say they have recovered DNA of the stomach bacterium from burials in Mexico linked to a 1540s epidemic that killed up to 80% of the country's native inhabitants. The team reports its findings in a preprint posted on the bioRxiv server on 8 February1.
This is potentially the first genetic evidence of the pathogen that caused the massive decline in native populations after European colonization, says Hannes Schroeder, an ancient-DNA researcher at the Natural History Museum of Denmark in Copenhagen who was not involved in the work. “It’s a super-cool study.”
Dead bodies and ditches
In 1519, when forces led by Spanish conquistador Hernando Cortés arrived in Mexico, the native population was estimated at about 25 million. A century later, after a Spanish victory and a series of epidemics, numbers had plunged to around 1 million.
The largest of these disease outbreaks were known as cocoliztli (from the word for ‘pestilence’ in Nahuatl, the Aztec language). Two major cocoliztli, beginning in 1545 and 1576, killed an estimated 7 million to 18 million people living in Mexico’s highland regions.
“In the cities and large towns, big ditches were dug, and from morning to sunset the priests did nothing else but carry the dead bodies and throw them into the ditches,” noted a Franciscan historian who witnessed the 1576 outbreak.
There has been little consensus on the cause of cocoliztli — although measles, smallpox and typhus have all been mooted. In 2002, researchers at the National Autonomous University of Mexico (UNAM) in Mexico City proposed that a viral haemorrhagic fever, exacerbated by a catastrophic drought, was behind the carnage2. They compared the magnitude of the 1545 outbreak to that of the Black Death in fourteenth-century Europe.
Bacterial genomics
In an attempt to settle the question, a team led by evolutionary geneticist Johannes Krause at the Max Planck Institute for the Science of Human History in Jena, Germany, extracted and sequenced DNA from the teeth of 29 people buried in the Oaxacan highlands of southern Mexico. All but five were linked to a cocoliztli that researchers think ran from 1545 to 1550.
Ancient bacterial DNA recovered from several of the people matched that of Salmonella, based on comparisons with a database of more than 2,700 modern bacterial genomes.
Further sequencing of short, damaged DNA fragments from the remains allowed the team to reconstruct two genomes of a Salmonella enterica strain known as Paratyphi C. Today, this bacterium causes enteric fever, a typhus-like illness, that occurs mostly in developing countries. If left untreated, it kills 10–15% of infected people.
It’s perfectly reasonable that the bacterium could have caused this epidemic, says Schroeder. “They make a really good case.” But María Ávila-Arcos, an evolutionary geneticist at UNAM, isn't convinced. She notes that some people suggest that a virus caused the cocoliztli, and that wouldn't have been picked up by the team’s method.
The question of origin
Krause and his colleagues’ proposal is helped by another study posted on bioRxiv last week, which raises the possibility that Salmonella Paratyphi C arrived in Mexico from Europe3.
A team led by Mark Achtman, a microbiologist at the University of Warwick in Coventry, UK, collected and sequenced the genome of the bacterial strain from the remains of a young woman buried around 1200 in a cemetery in Trondheim, Norway. It is the earliest evidence for the now-rare Salmonella strain, and proof that it was circulating in Europe, according to the study. (Both teams declined to comment on their research because their papers have been submitted to a peer-reviewed journal.)
“Really, what we’d like to do is look at both strains together,” says Hendrik Poinar, an evolutionary biologist at McMaster University in Hamilton, Canada. And if more ancient genomes can be collected from Europe and the Americas, it should be possible to find out more conclusively whether deadly pathogens such as Salmonella arrived in the New World from Europe.
The existence of Salmonella Paratyphi C in Norway 300 years before it appeared in Mexico doesn’t prove that Europeans spread enteric fever to native Mexicans, says Schroeder, but that hypothesis is reasonable. A small percentage of people infected with Salmonella Paratyphi C carry the bacterium without falling ill, so apparently healthy Spaniards could have infected Mexicans who lacked natural resistance.
Paratyphi C is transmitted through faecal material, and a collapse of social order during the Spanish conquest might have led to the poor sanitary conditions that are ripe for Salmonella spread, Krause and his team note in the paper.
Krause’s study offers a blueprint for identifying the pathogens behind ancient outbreaks, says Schroeder. His own team plans to look for ancient pathogens in Caribbean burial sites that seem to be linked to catastrophic outbreaks, and that were established after the Europeans arrived. “The idea that some of them might have been caused by Salmonella is now a distinct possibility,” he says.
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Here is the worst anti-science BS of 2016.
Donald Trump wasn't the only politician who lied about science this year.
2016 was a year of remarkable scientific breakthroughs. A century after Albert Einstein proposed his general theory of relativity, researchers proved him right when, for the first time ever, they were able to observe gravitational waves produced by two black holes that collided 1.3 billion years ago. Astronomers discovered a potentially habitable planet just 4.3 light-years from Earth. And scientists even came up with a good reason to put a bunch of adorable dogs in an MRI machine.
Unfortunately, there was a lot of anti-science nonsense this year, too—much of it from our political leaders. On issues ranging from climate change to criminal justice, our president-elect was a notable offender. But some of his rivals joined in as well. So did his nominees. And Congress. And members of the media. Here, in no particular order, are some of the most appalling examples. You can let us know in the comments which one you think is the worst.
Hurricane Matthew Truthers
In early October, as Hurricane Matthew approached the southeastern United States and officials ordered mass evacuations, a group of right-wing commentators alleged that the Obama administration was conspiring to exaggerate hurricane forecasts in order to scare the public about climate change. On October 5, Rush Limbaugh said hurricane forecasting often involved "politics" because "the National Hurricane Center is part of the National Weather Service, which is part of the Commerce Department, which is part of the Obama administration, which by definition has been tainted." He added, however, that Matthew itself was "a serious bad storm" and hadn't been politicized.
The next day, Matt Drudge took the theory a step further, tweeting, "The deplorables are starting to wonder if govt has been lying to them about Hurricane Matthew intensity to make exaggerated point on climate." He added, "Hurricane center has monopoly on data. No way of verifying claims." Drudge's tweets were widely condemned as dangerous and irresponsible. They also caught the attention of conspiracy kingpin Alex Jones:
.@DRUDGE This is exactly why they want to eradicate free speech... so you can't question official #globalwarming narrative. #altright #Trump https://t.co/udznluuBQO
— Alex Jones (@RealAlexJones) October 6, 2016
A day later, Limbaugh also went full Matthew Truther, declaring it "inarguable" that the government is "hyping Hurricane Matthew to sell climate change." Matthew would ultimately kill more than 40 people in the United States and hundreds in Haiti. It caused billions of dollars' worth of damage.
Congress Won't Lift the Gun Research Ban
Gun violence is a public health crisis that kills 33,000 people in the United States each year, injures another 80,000, and, according to an award-winning Mother Jones investigation, costs $229 billion annually. But as the Annals of Internal Medicine explained in a 2015 editorial, Congress—under pressure from the National Rifle Association—has for years essentially banned federal dollars from being used to study the causes of, and possible solutions to, this epidemic:
Two years ago, we called on physicians to focus on the public health threat of guns. The profession's relative silence was disturbing but in part explicable by our inability to study the problem. Political forces had effectively banned the Centers for Disease Control and Prevention and other scientific agencies from funding research on gun-related injury and death. The ban worked: A recent systematic review of studies evaluating access to guns and its association with suicide and homicide identified no relevant studies published since 2005.
Following the June 12 terrorist shootings that killed 49 people at a gay nightclub in Orlando, Democrats tried once again to lift the research ban. But as the Hill reported, "Republicans blocked two amendments that would have allowed the [CDC] to study gun-related deaths. Neither had a recorded vote."
Officials Face Charges in Flint Water Crisis
Perhaps the biggest scientific scandal in recent memory was the revelation that residents of Flint, Michigan—an impoverished, majority-black city—were exposed to dangerous levels of lead after government officials switched their drinking water source. Lead poisoning can cause learning disabilities and behavioral problems, along with a variety of other serious health issues. Officials ignored—and then publicly disputed—repeated warnings that Flint's water was unsafe to drink. According to one study, the percentage of Flint children with elevated lead levels doubled following the switchover. The water crisis may also be to blame for a deadly outbreak of Legionnaires' disease.
Since April 2016, Michigan Attorney General Bill Schuette has filed charges against 13 current and former government officials for their alleged role in the crisis. On December 19, Schuette accused two former emergency managers—officials who had been appointed by the governor to oversee Flint's finances with minimal input from local elected officials—of moving forward with the switchover despite knowing the situation was unsafe. According to the charging document, Darnell Earley conspired with Gerald Ambrose and others to "enter into a contract based upon false pretenses [that required] Flint to utilize the Flint River as its drinking water source knowing that the Flint Water Treatment Plant…was unable to produce safe water." The document says that Earley and Ambrose were "advised to switch back to treated water" from Detroit's water department (which had previously supplied Flint's water) but that they failed to do so, "which caused the Flint citizens' prolonged exposure to lead and Legionella bacteria." The attorney general also alleged that Ambrose "breached his duties by obstructing and hindering" a health department investigation into the Legionnaires' outbreak. Earley and Ambrose have pleaded not guilty.
Trump's Budget Director Isn't Sure the Government Should Fund Zika Research
Rep. Mick Mulvaney (R-S.C.), Donald Trump's choice to head the White House Office of Management and Budget, isn't just a global warming denier. As Mother Jones reported, he recently questioned whether the government should even fund scientific research. In September, Mulvaney took to Facebook to discuss the congressional showdown over urgently needed funding for the Zika epidemic—money that would pay for mosquito control, vaccine studies, and research into the effects of the virus. (Among other disputes, Republicans sought to prevent Planned Parenthood from receiving Zika funds.)
"[D]o we need government-funded research at all[?]" wrote Mulvaney in his since-deleted post. Even more remarkably, he went on to raise doubts about whether Zika really causes microcephaly in babies. As Slate's Phil Plait noted, "There is wide scientific consensus that zika and microcephaly are linked, and had been for some time before Mulvaney wrote that."
The House "Science" Committee
The House Committee on Science, Space, and Technology is quickly becoming one of the most inaccurately named entities in Washington. For the past several years, Rep. Lamar Smith (R-Texas) has used his position as chairman of the committee to harass scientists through congressional investigations. He's even accused researchers at the National Oceanic and Atmospheric Administration of having "altered historic climate data to get politically correct results" about global warming. As we explained in February, "Smith is determined to get to the bottom of what he sees as an insidious plot by NOAA to falsify research. His original subpoena for internal communications, issued last October, has been followed by a series of letters to Obama administration officials in NOAA and other agencies demanding information and expressing frustration that NOAA has not been sufficiently forthcoming."
Fast-forward to December 2016, when someone working for Smith decided to use the committee Twitter account to promote an article from Breitbart News titled "Global Temperatures Plunge. Icy Silence from Climate Alarmists." (Breitbart is the far-right website that was formerly run by chief Trump strategist Steve Bannon. In addition to climate denial, Bannon has said the site is "the platform for the alt-right," a movement that is closely tied to white nationalism.)
.@BreitbartNews: Global Temperatures Plunge. Icy Silence from Climate Alarmists https://t.co/uLUPW4o93V
— Sci,Space,&Tech; Cmte (@HouseScience) December 1, 2016
Unsurprisingly, actual scientists weren't pleased.
GOP Platform Declares Coal Is "Clean"
Republicans' devotion to coal was one of the defining environmental issues of the 2016 campaign. Trump promised to revive the struggling industry and put miners back to work by repealing "all the job-destroying Obama executive actions." Those commitments were reflected in an early version of the GOP platform, which listed coal's many wonderful qualities and said that Republicans would dismantle Obama's Clean Power Plan, which limits emissions from coal-fired power plants. That didn't go far enough for GOP activist David Barton, who convinced delegates at the party's convention to add one additional word to the text. "I would insert the adjective 'clean,'" said Barton. "So: 'The Democratic Party does not understand that coal is an abundant, clean, affordable, reliable domestic energy resource.'" Barton's wording change was approved unanimously. As Grist noted at the time, "For years the coal industry—and at one point, even President Obama—promoted the idea of 'clean coal,' that expensive and imperfect carbon-capture-and-storage technology could someday make coal less terrible. But there's no way it is clean."
Global Warming Deniers in the GOP Primaries
As 2016 kicked off, there were still 12 candidates competing for the Republican presidential nomination. Nearly all of them rejected the overwhelming scientific consensus that humans are the main cause of global warming. (The GOP contenders who spoke most forcefully in favor of the science—Lindsey Graham and George Pataki—both dropped out of the race in late 2015.)
As recently as December 2015, Trump declared that "a lot of" the global warming issue is "a hoax." His chief rival, Ted Cruz, said in February that climate change is "the perfect pseudoscientific theory" to justify liberal politicians' efforts to expand "government power over the American citizenry." In a debate in March, Marco Rubio drew loud applause when he said, "Well, sure, the climate is changing, and one of the reasons why the climate is changing is the climate has always been changing...But as far as a law that we can pass in Washington to change the weather: There's no such thing." Moments later, John Kasich said, "I do believe we contribute to climate change." But he added, "We don't know how much humans actually contribute."
In 2015, Ben Carson told the San Francisco Chronicle, "There is no overwhelming science that the things that are going on are man-caused and not naturally caused." A few months earlier, Jeb Bush said, "The climate is changing. I don't think the science is clear of what percentage is man-made and what percentage is natural…For the people to say the science is decided on this is just really arrogant." In one 2014 interview, Rand Paul seemed to accept that carbon pollution is warming the planet; in a different interview, he said he's "not sure anybody exactly knows why" the climate changes. Mike Huckabee claimed in 2015 that "a volcano in one blast will contribute more [to climate change] than a hundred years of human activity." (That's completely wrong.) In 2011, Rick Santorum called climate change "junk science." In 2008, Jim Gilmore said, "We know the climate is changing, but we do not know for sure how much is caused by man and how much is part of a natural cycle change."
Two other GOP candidates, Chris Christie and Carly Fiorina, seemed to largely accept the science behind climate change, but neither of them had much of a plan to deal with the problem.
Trump's (Other) Wars on Science
Trump's rejection of science goes well beyond basic climate research. Here are some of his more outlandish claims from the past year:
Despite DNA evidence, Trump still thinks the Central Park Five are guilty. In 1989, five black and Hispanic teenagers were charged with the brutal rape of a white woman in New York's Central Park. Trump proceeded to pay for inflammatory ads in the city's newspapers decrying the "permissive atmosphere which allows criminals of every age to beat and rape a helpless woman." He called on lawmakers to "bring back the death penalty and bring back our police!" The defendants, most of whom had confessed to involvement in the rape, were convicted. They were eventually exonerated by DNA evidence and a confession from the actual rapist. But Trump still isn't persuaded by the scientific evidence. "They admitted they were guilty," he told CNN in October. "The police doing the original investigation say they were guilty. The fact that that case was settled with so much evidence against them is outrageous." As Sarah Burns, who made a documentary about the case, noted in the New York Times, "False confessions are surprisingly common in criminal cases. In the hundreds of post-conviction DNA exonerations that the Innocence Project has studied, at least one in four of the wrongly convicted had given a confession."
Trump mocks football players for worrying about brain damage from concussions. In October, Trump praised a woman who returned to his Florida rally shortly after she had fainted from the heat. "That woman was out cold, and now she's coming back," he said. Trump, who once owned a USFL football team, added, "See, we don't go by these new, and very much softer, NFL rules. Concussions—'Uh oh, got a little ding on the head? No, no, you can't play for the rest of the season'—our people are tough." As the Washington Post pointed out, "Recent MRI scans of 40 NFL players found that 30 percent had signs of nerve cell damage. Florida State University College of Medicine's Francis X. Conidi, a physician and author of the study, said in a statement that the rates of brain trauma were 'significantly higher in the players' than in the general population. In the spring, the NFL acknowledged a link between football and degenerative brain diseases such as chronic traumatic encephalopathy, which is associated with symptoms such as depression and memory loss."
Trump meets with anti-vaxxers. Trump has long been a proponent of the discredited—and dangerous—theory that vaccines cause autism. "I'm not against vaccinations for your children, I'm against them in 1 massive dose," Trump tweeted in 2014. "Spread them out over a period of time & autism will drop!" He made the same argument at a 2015 GOP debate, causing a spike in Google searches for information about the supposed vaccine-autism connection. Since then, Trump hasn't said much more about the issue in public. But according to Science magazine, he met privately with a group of leading anti-vaccine activists at a fundraiser in August. The group reportedly included Andrew Wakefield, the lead researcher behind the seminal study (since retracted) of the vaccine-autism connection. Science reported that "Trump chatted with a group of donors that included four antivaccine activists for 45 minutes, according to accounts of the meeting, and promised to watch Vaxxed, an antivaccine documentary produced by Wakefield…Trump also expressed an interest in holding future meetings with the activists, according to participants."
Trump says there is no drought. During a May campaign stop in Fresno, California, Trump offered a bizarre take on the state's "insane" water problems, implying that there wasn't actually a drought. (There was and still is.) He suggested that the state had "plenty of water" but that "they're taking the water and shoving it out to sea" in order to "protect a certain kind of three-inch fish." As FactCheck.org explained, "California is in its fifth year of a severe 'hot' drought," and "officials release fresh water from reservoirs primarily to prevent salt water from contaminating agricultural and urban water supplies." (A much smaller proportion of water is released from reservoirs to preserve habitat for Chinook salmon, the "three-inch" delta smelt, and other fish.)
Trump wants to use hairspray. Trump has repeatedly complained that efforts to protect the ozone layer are interfering with his hair routine. "You're not allowed to use hairspray anymore because it affects the ozone," he said in May, arguing that more environmentally friendly hair products are only "good for 12 minutes." He added, "So if I take hairspray and I spray it in my apartment, which is all sealed, you're telling me that affects the ozone layer?…I say no way, folks. No way. No way." FactCheck.org actually went through the trouble of asking scientists whether Trump's strategy of using hairspray indoors would help contain the ozone-destroying chemicals. "It makes absolutely no difference!" said Steve Montzka, a NOAA chemist. "It will eventually make it outside."
Jill Stein (Yep, She Deserves Her Very Own Category)
Vaccines. Of course, science denial isn't confined to the political right. During the 2008 presidential campaign, both Obama and Hillary Clinton flirted with the notion that vaccines could be causing autism and that more research was needed on the issue—long after that theory had been discredited. Obama and Clinton have abandoned these misguided views, but Green Party presidential candidate Jill Stein is apparently still concerned. In July, she told the Washington Post that vaccines are "invaluable" medications but that the pharmaceutical industry has too much influence over safety determinations from the Food and Drug Administration and the CDC. "As a medical doctor, there was a time when I looked very closely at those issues, and not all those issues were completely resolved," she said. "There were concerns among physicians about what the vaccination schedule meant, the toxic substances like mercury which used to be rampant in vaccines. There were real questions that needed to be addressed. I think some of them at least have been addressed. I don't know if all of them have been addressed."
GMOs. There are plenty of reasonable debates surrounding the use of genetically modified crops. But when it comes to their impact on human health, scientists are pretty much in agreement: GMOs are safe to eat. Once again, Stein isn't convinced. During the 2016 campaign, Stein called for a moratorium on the introduction of new genetically modified organisms and a "phaseout" of current genetically modified crops "unless independent research shows decisively that GMOs are not harmful to human health or ecosystems." Stein's website promised that her administration would "mandate GMO food labeling so you can be sure that what you're choosing at the store is healthy and GMO-free! YOU CAN FINALLY FEEL SECURE THAT YOUR FAMILY IS EATING SAFELY WITH NO GMO FOODS ON YOUR TABLE!" That page also featured a 2013 video of Stein saying, "This is about what we are eating. This is about whether we are going to have a food system at all. This is about whether our food system is built out of poison and frankenfood."
The Climate-Denying Cabinet
Trump has loaded up his incoming administration with officials who, to varying extents, share his views on climate change. Vice President-elect Mike Pence once called global warming a "myth," though he now acknowledges that humans have "some impact on climate." Scott Pruitt, Trump's pick to run the Environmental Protection Agency, wrote in May that "scientists continue to disagree about the degree and extent of global warming and its connection to the actions of mankind." Energy secretary nominee Rick Perry once alleged that "a substantial number" of climate scientists had "manipulated data." Trump's interior secretary nominee, Ryan Zinke, believes that climate change is "not a hoax, but it's not proven science either." Ben Carson (see above) is slated to run the Department of Housing and Urban Development, an agency facing serious challenges from global warming. Mulvaney, the incoming White House budget director, has said we shouldn't abandon domestic fossil fuels "because of baseless claims regarding global warming." Attorney general nominee Jeff Sessions claimed in 2015 that predictions of warming "aren't coming true."
Interfering with government scientists?
Trump hasn't even been sworn in yet, but already there are troubling signs that his administration may attempt to interfere with the work of government scientists and experts.
Energy Department questionnaire. The president-elect's transition team submitted a questionnaire to the Department of Energy asking for a list of employees and contractors who had worked on the Obama administration's efforts to calculate the "social cost of carbon"—that is, the dollar value of the health and environmental damage caused by burning fossil fuels. The transition team also asked for a list of staffers who attended UN climate negotiations. As the Washington Post explained, the questionnaire "has raised concern that the Trump transition team is trying to figure out how to target the people, including civil servants, who have helped implement policies under Obama." (The department didn't comply with the request, and the Trump team ultimately disavowed the questionnaire after facing criticism.)
Earth science at NASA. One of Trump's space advisers, Bob Walker, has repeatedly floated the idea that the administration should begin to remove Earth science from NASA's portfolio. NASA's Earth science program is well known for producing some of the world's most important climate change research, and Walker's proposal has sparked an outcry among many in the scientific community. (Walker has suggested shifting the work to NOAA, but the incoming administration hasn't proposed giving NOAA additional funding, and Walker's critics have called the plan unworkable.) Trump hasn't actually adopted Walker's idea, and scientists such as David Grinspoon, an astrobiologist who receives NASA funding, are optimistic that he won't. But if Trump does attempt to gut NASA's research efforts, the backlash could be intense. "We're not going to stand for that," said Grinspoon on our Inquiring Minds podcast. "We're going to keep doing Earth science and make the case for it. We'll get scientists to march on Washington if we have to. There's going to be a lot of resistance."
Abortion and Breast Cancer
For years, abortion rights opponents have insisted that abortion can cause breast cancer. That claim was based on a handful of flawed studies and has since been repeatedly debunked by the scientific community. According to the American Congress of Obstetricians and Gynecologists, "More rigorous recent studies demonstrate no causal relationship between induced abortion and a subsequent increase in breast cancer risk." Influential anti-abortion groups have frequently emphasized a more nuanced but still misleading version of the breast cancer claim: that having an abortion deprives women of the health benefits they would otherwise receive by giving birth. That argument has found its way into an official booklet that the state of Texas provides to women seeking abortions. According to the latest version of the booklet, released in early December:
Your pregnancy history affects your chances of getting breast cancer. If you give birth to your baby, you are less likely to develop breast cancer in the future. Research indicates that having an abortion will not provide you this increased protection against breast cancer.
"The wording in [the Texas booklet] gets very cute," said Otis Brawley, the American Cancer Society's chief medical officer, in an interview with the Washington Post. "It's technically correct, but it is deceiving." Here's the problem, as explained by the Post:
Women who deliver their first baby to full-term at 30 years or younger face a decreased long-term risk of breast cancer than women who have their first baby at older than 30 or 35, or who never deliver a baby at all…Having a baby does provide increased protection against breast cancer, but it doesn't mean that having an abortion affects your risk one way or another. For example, women who deliver a child before 30, but then have an abortion after their first child, still have a decreased risk of breast cancer, said Brawley, who described himself as "pro-life and pro-truth."
Pence Denies the Existence of Implicit Bias in Police Shootings
During her first debate with Trump, Clinton supported efforts to retrain police officers to counter so-called "implicit bias." She noted that people in general—not just police officers—tend to engage in subconscious racism. But she added that in the case of law enforcement, these biases "can have literally fatal consequences." During the vice presidential debate a few days later, Pence blasted Clinton and other advocates of police reform for "bad-mouthing" cops. He criticized people who "seize upon tragedy in the wake of police action shootings… to use a broad brush to accuse law enforcement of implicit bias or institutional racism." That, he said, "really has got to stop."
Pence's comments were a gross misrepresentation of a key scientific issue in the national debate over police killings of African Americans. Implicit bias does not, as he implied, refer to intentional, overt bigotry or to systematic efforts by law enforcement to target minorities (though there are plenty of examples of those, too). Rather, implicit bias refers to subconscious prejudices that affect people's split-second decisions—for example, whether or not a cop shoots an unarmed civilian. As Chris Mooney explained in a 2014 Mother Jones story:
This phenomenon has been directly studied in the lab, particularly through first-person shooter tests, where subjects must rapidly decide whether to shoot individuals holding either guns or harmless objects like wallets and soda cans. Research suggests that police officers (those studied were mostly white) are much more accurate at the general task (not shooting unarmed people) than civilians, thanks to their training. But like civilians, police are considerably slower to press the "don't shoot" button for an unarmed black man than they are for an unarmed white man—and faster to shoot an armed black man than an armed white man.
And as Mooney noted, acknowledging that implicit biases are common—something Pence refused to do—allows scientists and law enforcement to devise trainings that seek to counter the problem.
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Science News for Students editors’ top picks for 2016.
Here’s the year in review, focusing on the top 10 major stories.
JANET RALOFF
DEC 22, 2016 — 7:00 AM EST
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What were our editors' top stories of 2016? Read on to find out.
E. OTWELL
This year saw a redesign of Science News for Students. And along with it came a steady rise in readers. From far and wide, around half a million of you check in each month (coming from more than 100 countries). To serve you better, we have rolled out more topical stories, many of them posting on the very day they made news. We know that you’ve noticed and voted with your phone taps and mouse clicks as to which you found most interesting.
But we editors sometimes have a different idea of which are the most important stories. Some have the potential to prove game-changers in science and engineering. Others point to trends or issues that stand poised to affect us or our world. So sit back and review our top 10 hits for 2016. If you missed them earlier in the year, here’s your chance to catch up. Enjoy!
10: New insights into adolescent stress
Stress is an annoying but natural part of life. Scientists are figuring out what primes the human body to experience stress.
Firesam!/Flickr (CC-BY ND 2.0)
Losing sleep over an upcoming tryout? Fearful about meeting your nemesis in the hallway or on the ball field? Stress is hardly new, especially in teens. But what primes the body to experience stress has remained somewhat sketchy. This year, science worked toward demystifying that.
For instance, animal data showed that binge drinking — which is common in many teens — appears capable of rewiring the brain in ways that make it more prone to stress. And a source in our story argues that “what happens in rats is suggestive of what happens in humans.” Also stressful: confronting people who strongly disagree with you. But standing up for your beliefs in these circumstances can actually counter that stress, researchers now report.
9: Young ears under assault
Subjecting your ears to loud music or other high-volume sounds puts hearing and other organs of the body at risk. In at least one study, almost one-third of all high-school students reported a nonstop ringing in their ears, known as tinnitus. The students were also abnormally sensitive to loud sounds. Both symptoms point to emerging hearing damage that could prove permanent and likely to worsen. And even a single event, such as attending a rock concert without ear protection, can cause temporary hearing loss or damage.
8: Hate incidents at schools rise after U.S. elections
At least 867 hate incidents took place in the 10 days following the November 2016 U.S. elections, a legal group reported. At least 648 of those were based on racism. And about three out of every eight cases took place at schools, sometimes even elementary schools. Our story pointed to social science studies that identify the long-term impacts of racism and how they can harm health. No one has to stand by and watch, though. We shared advice from psychologists who study racism on what students can do when they witness or are the targets of such hateful acts or taunts.
7: Microplastics cause aquatic harm
Tiny bits of plastic, called microplastics, can be found in oceans and other bodies of water worldwide.
Image by 5Gyres, courtesy of Oregon State University/Flickr (CC-BY-SA 2.0)
Tiny plastic beads and lint have been washing down drains and into waterways. They may have come from cleansing products or the breakdown of synthetic fabrics as they are laundered. New studies have been showing that animals in the sea eat those plastic bits, commonly referred to as microplastics. People who eat those oysters might also down the plastics the shellfish carried. One study found that baby fish may actually prefer this plastic to their normal food, even though it won’t give them the energy to keep them alive. And one likely reason for this unhealthy behavior: Some of that plastic actually smells like true food.
6: New insights into pollution’s harm
Most everyone knows that breathing heavily polluted air can be deadly. In fact, new data show, it has become the world’s fourth leading cause of early death. Dirty air also fosters obesity. The study that determine that was in rats, although our sources noted it’s “highly likely that this is happening in humans.” Especially disturbing, a major new paper found that when it comes to the pollution released by burning coal, oil or gas — the fossil fuels — children suffer more than adults do.
One troubling source of pollution that people intentionally expose themselves to are the vapors from electronic cigarettes. In fact, e-cigs have overtaken cigarettes as the leading tobacco product used by teens. And new data show that teens who had no intention to smoke tobacco cigarettes often do after first experimenting with e-cigarettes.
But there are additional reasons why vaping may be very risky. A trio of scientists from different labs unveiled new data from tests in cells and animals. These showed e-cig vapors can impair behavior, harm the immune system, harm male sperm and threaten heart health. Through its effects on the DNA of cells in the gums and mouth, e-cig vapors can put your smile at risk. But all vapors are not alike. In fact, those vapors become more toxic the hotter an e-cigarette gets — and the more it’s used.
5: More details emerge about our solar system
Saturn’s moon Enceladus is home to a vast, salty ocean buried beneath a frozen surface.
NASA/JPL/Space Science Institute
Remember when Pluto was demoted from planethood? Well January 2016 saw the emergence of data suggesting our solar system may still host a ninth planet after all — one orbiting far, far beyond Pluto. The best estimates suggest it would be at least 10 times as massive as Earth and circle the sun once every 17,000 years.
Jupiter, the biggest planet, got a visitor this year. The Juno spacecraft is expected to spy on the planet for some 20 months. Yet even before Juno arrived, Earth-based studies showed that Jupiter’s stormy atmosphere sports turbulence that can stretch nearly 100 kilometers (60 miles) below the cloud tops. And while the planet is relatively cold, its Great Red Spot is so scalding hot that it could melt iron.
And Enceladus, a moon of Saturn, now appears to host a vast, salty ocean beneath its frozen surface. Not only might this moon host life, but it also appears to play an active role in the survival of its parent planet’s biggest ring.
4: Zika explodes in the Americas
Zika, a mosquito-borne disease, blazed across Brazil in 2015. But it erupted to global attention in January 2016 when thousands of babies were born with unusually small heads (and other problems). But that was just the beginning. In all, Science News for Students has run 10 stories throughout the year describing the disease and a trail of birth defects and other problems that have turned up in its wake. These include brain and joint abnormalities, eye oddities and the death of certain types of important brain cells.
3: Women in the sciences and engineering
Although women make up at least half of the adult population, they account for only a bit more than one in every four scientists and engineers. A major story in our magazine this year delved into the history of women in research (it used to be a lot worse) and the prospects for improvement. An accompanying story pointed to studies showing how adults can sabotage a student’s attempt to train for a career in science or math. But another 10 blog posts showcased more than 100 women who beat the odds to find a successful career in research of all types. You can read about them and more here in our new collection containing stories about Women in STEM (science, technology, engineering and math).
2: Climate change impacts intensify
Earth’s climate has been changing notably in recent decades. That’s no surprise. But a spate of new studies and reports that came out this year point to the worsening impacts of those changes. These changes eventually will impact every person and nearly every ecosystem on the planet. Last year, many areas suffered from record heat, and not just in summer. That heat may turn out to be normal for the globe within a decade.
As the Arctic warms, sea ice is disappearing. Polar bears now spend less time on the ice and more time swimming in the water in search of food.
Amanda Graham/Flickr (CC-BY-NC-ND 2.0)
Another study showed that Earth’s recent warming has caused sea levels to rise faster during the 20th century than at any time during in the previous 2,800 years. This prompted people living on an island above Alaska's north coast in August to vote to abandon their island home. Sea-level rise had already washed away much of the island, turning these people into climate migrants.
Polar bears normally summer atop ice floes, diving off when it’s time to hunt. But with less ice on the sea they’re swimming more than ever in search of food. One young female’s nonstop swim lasted nine days. Things could get far worse. And soon. Arctic sea ice reached a record low in March 2016. By 2050, it could fully disappear during summer months, a new analysis reported. That would be the first time the Arctic was warm enough to be ice-free in 125,000 years.
1: Gravity waves discovered — at last!
In November 1915, Albert Einstein unveiled a new way of looking at gravity. The math to explain this came to be known as general relativity. In 1916, Einstein realized that this new theory also predicted the existence of gravitational waves — now commonly called gravity waves. Yet it would be February 2016, a whole century, before anyone confirmed that gravity waves exist. Four months later, scientists offered a second confirmation of the phenomenon. We outlined the exploration for those mystery waves. We also provided an explainer on what they are and how they differ from most other waves. As one astronomer who was not involved with either project concluded: “The era of gravitational wave astronomy is upon us.” This new field has also given rise to a whole new unit for measuring massive outpourings of energy. It’s the yottawatt!
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El Niño on a warming planet may have sparked the Zika epidemic, scientists report.
A new disease model produced an unusually high disease transmission potential in the tropics for the year 2015, including in Colombia and Brazil, the countries hit hardest by Zika.
In a world characterized by rising temperatures, deforestation and other human influences on the environment, the spread of infectious disease is a hot topic. Many recent studies suggest that environmental changes can affect the transmission of everything from malaria to the Zika virus — and it’s increasingly important to understand these links, scientists say.
This week, a new study has provided new evidence that environmental changes can increase the threat of disease. It concludes that unusually warm temperatures caused by 2015’s severe El Niño event — probably compounded by ongoing climate change — may have aided in the rapid spread of the Zika virus in South America that year. And while there are many complex factors at play in the spread of mosquito-borne diseases, the study may help scientists better prepare for the kinds of future effects we might see in our warming world.
“The start of the mission was simple — trying to address where the risk will be, where is it going to move next, where could Zika happen on the planet on a global scale,” said Cyril Caminade, a research fellow at the University of Liverpool and the new study’s lead author. To that end, the authors designed a study that would help them determine how climatic changes have impacted the mosquito-borne transmission of Zika.
There are two main species of mosquito known to carry the Zika virus — Aedes aegypti, or the yellow fever mosquito, which is widespread in the tropics; and Aedes albopictus, or the Asian tiger mosquito, which lives in both tropical and temperate regions of the world. Scientists also believe Zika can be sexually transmitted, but the new study focused only on mosquito transmission.
For the study, the researchers collected published information on the distribution of these two mosquito species and how temperature variations can affect them. Studies suggest, for instance, that up to a certain point, rising temperatures can cause mosquitoes to bite more frequently. The researchers also collected global historical climate data from the past few decades and used all the information to build a model of Zika transmission worldwide.
The model produced an unusually high disease transmission potential in the tropics for the year 2015, including in Colombia and Brazil, the countries hit hardest by Zika. Similar results occurred between 1997 and 1998, one of the only other times on record to experience such a brutal El Niño event.
“[O]ur model indicates that the 2015 El Niño event, superimposed on the long-term global warming trend, has had an important amplification effect,” the researchers note in the paper.
The model also helped the researchers identify the ideal seasonal climate conditions for Zika transmission around the world. In South America, for instance, the model suggests that the potential for transmission should peak in the winter and spring.
In the southeastern U.S., on the other hand, summer is ideal. In fact, the model suggests this region has a high potential for disease transmission during this time, due partly to the high temperatures and partly to the fact that both mosquito species are found there.
That said, reports of Zika have been limited in the U.S. so far — and this speaks to the complexity of vector-borne disease transmission, Caminade said. Climate can certainly play a significant role in setting up the right conditions for an outbreak, but epidemics also depend on many other factors, including population density, access to healthcare and the use of pesticides and other anti-mosquito interventions in any given location. Some of these factors — which were not accounted for in the new study — can probably explain why there hasn’t been much Zika transmission in the U.S. so far.
Caminade also pointed out that after a population has been exposed to a mosquito-borne disease like Zika, a phenomenon called “herd immunity” often occurs — this happens when so many people have already been exposed, and developed an immunity, that there aren’t enough new people left to infect to continue the epidemic. This is the probably part of the reason we didn’t see Zika epidemics in other tropical parts of the world in 2015, despite the new study’s results. And some experts have suggested that herd immunity will likely cause the current situation in South America to burn itself out within a few more years.
But Caminade cautions that there’s still the potential for Zika outbreaks in other parts of the world where the conditions are right, including the United States and even southern Europe. The result would likely be milder than what’s been experienced in South America in the past year, but there’s “still risk,” he said.
According to Caminade, one of the study’s major takeaway points is that extreme climate conditions can lead to all kinds of unusual events — droughts, floods and wildfires are only a few examples — and disease outbreak is just one more potential disaster scientists should be looking out for when these conditions occur.
And such events may only be exacerbated by future climate change. Some studies have suggested that the kinds of “monster” El Niño events seen in 1997 and 2015 may be more likely in a warmer world, Caminade pointed out. But he added that scientists wishing to make more precise predictions about the future spread of disease must take a wide variety of factors into account — climate is just one of them.
“I won’t overplay the role of climate for the future,” he said. “It’s still a disease, and there are still parameters which are going to be very important.”
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