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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Warmer weather could bring fresh Zika misery.
Zika may have gone quiet during the winter, but as mosquito season approaches it looks like it could spread further and have longer term health effects than we thought.
Zika may have gone quiet during the winter, but as mosquito season approaches it looks like it could spread further and have longer term health effects than we thought
Zika is especially bad for babies
Ueslei Marcelino/Reuters
By Jessica Hamzelou
ZIKA virus is set to return to the fore once the mosquito season starts again in the coming months, and it looks like it could spread further and do more damage than we thought.
Cases of Zika virus – and the neurological disorders it causes in babies – have been declining across the Americas in recent months, in part because of a drop in mosquito numbers during winter. There is also evidence that people in affected countries are developing immunity to the virus – although this may be short-lived if the virus evolves, or as newly vulnerable people are born or move to affected areas.
Yet while Zika may have gone quiet, research into the virus has continued in earnest. It was assumed that only a few species of mosquito could spread Zika, including Aedes aegypti and Aedes albopictus, found in tropical regions across the globe. But now it seems many more species could carry the virus, including 26 not previously considered a threat (eLife, doi.org/b2ps). Some are found in more northerly reaches of the US, to which Zika hasn’t yet spread. The onset of warmer weather in the US could bring many more cases, as mosquitoes begin to breed and feed on blood.
Meanwhile, other means of transmission may further propagate the virus. Gabriela Paz-Bailey and her colleagues at the US Centers for Disease Control (CDC) have been investigating how long Zika can remain in human body fluids. It seems to linger in semen the longest; of the 55 infected men who have donated semen samples so far, half had cleared the virus within a month, but 5 per cent still had traces three months later. Bailey presented her findings at the Conference on Retroviruses and Opportunistic Infections in Seattle last month.
Although only a handful of sexually transmitted cases have been identified, there are probably more out there, says Laurent Hébert-Dufresne at the Santa Fe Institute in New Mexico. What’s more, the discovery that Zika survives for so long in semen means that men who have sex with men are at particular risk of becoming infected and spreading the virus. They are also less likely to be tested for the virus, Hébert-Dufresne adds.
Testing is offered during pregnancy as babies born to infected women are at risk of microcephaly, which causes them to have small heads, along with nervous system disorders. Last week, the CDC reported a 20-fold increase in such birth defects in Massachusetts, North Carolina and Georgia. Even babies that appear healthy at birth can develop neurological problems down the line, and it may be a while before the full impact of the virus is known.
Those aren’t the only possible side effects of Zika infection in the womb. Problems with vision, limb development, hearing, digestion and breathing are beginning to emerge in babies exposed to Zika. Around 42 per cent of infected pregnant women have babies with at least one of these issues (JAMA Pediatrics, doi.org/b2qz).
“It does more than microcephaly,” says Catherine Spong, deputy director of the US National Institute of Child Health and Human Development.
Zika may have consequences for adults, too. A handful of cases of Guillain-Barré syndrome, in which a person’s immune system attacks their own nerves, have been reported. Research in mice also suggests the virus may affect the growth of neurons in adult brains, and potentially shrink the testicles.
Other question marks surround the presence of the virus in South East Asia; we don’t yet know if it is as dangerous, or how it might spread. “We see Zika there, but we’re not sure if it’s the same, or if there could be larger outbreaks,” says Alain Kohl at the University of Glasgow in the UK.
Globally, efforts are under way to control the virus by destroying mosquito habitats, killing the insects or using genetically modified insects to drive them into oblivion. Several groups are also working on vaccines for the virus, one of which appears to protect mice and monkeys.
For now, though, there are no treatments available. “Until we get to a situation where we can treat it effectively, we need to be worried about it,” says Kohl.
This article appeared in print under the headline “Dormant Zika is back for round two”
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Plague! How to prepare for the next pandemic.
Globalisation makes the spread of a worldwide killer disease inevitable. The last Ebola outbreak nearly got out of control, but it showed what we need to do.
Globalisation makes the spread of a worldwide killer disease inevitable. The last Ebola outbreak nearly got out of control, but it showed what we need to do
plague artwork
Brian Larossa
By Debora MacKenzie
IN 1347, an epidemic of unimaginable ferocity struck Europe. People first experienced flu-like symptoms, but within days painful swellings developed, which turned black, split open and oozed pus and blood. The Great Pestilence, later dubbed the Black Death, swept across the continent within four years, killing up to half the population. The disease persisted in Europe until the 1700s, always circulating somewhere, killing people off.
We speak of it nowadays as history. In fact, it is more like natural history: infectious disease is part of the ecology of our species. Until 1900, and despite considerable competition from violence and starvation, it was our biggest killer, causing half of all human deaths. Now, it accounts for fewer than a quarter of all deaths worldwide, most of them in poor, tropical regions. In rich countries it is only a few per cent. And the toll is falling.
But we shouldn’t be complacent: plagues will return. The 1960s notion that infectious disease was on the way out ended when HIV appeared in the 1980s. Since then, many infections like bird flu, SARS and Zika have caused alarm. But it took a near-disaster – the worst ever outbreak of Ebola – to scare the inertia out of governments. As a result, we are at last preparing for the inevitable. A clutch of programmes being launched this year will improve our grip on microbial killers. And the world now has an emergency medical response team – which, astonishingly, it never had before. But we aren’t there yet. If a novel virus struck now, we would still be in trouble.
For all our high-tech modernity, and in many ways, because of it, the risk that new infectious diseases will evolve is actually getting worse. Pathogens began circulating regularly among humans only after we started farming and settled in towns. One reason was that we caught infections from our livestock: flu from ducks, tuberculosis from cows. But crucially, there were enough of us in close proximity that a germ could always find a new host and keep spreading, persisting among people and adapting to us.
Now we are crowding into cities and travelling more, especially within the tropics where pathogen diversity is highest. That plus globalised trade, migration and climate change reshuffle wildlife, people and pathogens. Farms and towns invade the habitats of animals with viruses that can jump to us, or to our densely packed livestock, also booming as demand for animal protein soars.
Public health experts have been warning for years of “emerging” diseases, which can go from unknown to epidemic if the pathogen mutates or the ecology of its hosts changes to make its spread easier. And it is viruses that epidemiologists are most worried about. Bacteria can be deadly, and antibiotic resistance could mean diseases from gonorrhoea to ordinary bladder infections become incurable, but work has at least begun on new drugs. In contrast, viruses can evolve and spread faster, there are thousands we know nothing about, and we have few drugs against them. The worst emerging infections since 2000 have all been viruses.
None is more alarming than the 2014 outbreak of Ebola in West Africa. The virus infected 50 times more people than any previous outbreak, and reached big cities for the first time. As a bat virus still unaccustomed to humans, it spread fairly slowly, but an even slower international response allowed it to kill more than 11,000 people before old-fashioned methods, like isolating cases and quarantining their contacts, snuffed the outbreak out.
There was no other option. We were unable to produce a vaccine in time even though we already had experimental Ebola drugs and vaccines, and their deployment was accelerated, with regulation and manufacture taking months instead of the usual years. Researchers have since discovered that as it spread the Ebola virus was adapting to people, and getting better at transmitting. It almost spiralled out of control in Nigeria. “The world was close to an abyss,” says Tom Frieden, outgoing head of the US Centers for Disease Control and Prevention.
To combat the next plague, we will need vaccines, drugs and diagnostic tools – and just as importantly, some way to deploy them effectively. “We do not have that,” says Jeremy Farrar, head of UK medical research agency the Wellcome Trust. But we might if, in the wake of Ebola, we can build on momentum in three key areas: working out what the enemy is, arming ourselves against it and being ready to act forcefully and fast.
1 Know your enemy
First, what should we prepare for? “Spotting the next HIV or SARS before it strikes is virtually impossible,” says Ab Osterhaus, head of the new Research Center for Emerging Infections and Zoonoses in Hannover, Germany. “There are too many viruses in too many species, interacting with humans and evolving in unpredictable ways.” To narrow the field, he says, we need “a detailed understanding of when, where and how viruses are moving from wildlife to people”. Because, like the historical plagues, the next big disease is likely to be one that has made the leap from other animals to us.
In December, Mark Woolhouse and his colleagues at the University of Edinburgh, UK, reviewed what we know about such viruses. They identified 37 already able to spread from human to human, though poorly, that could become more contagious. These range from virtual unknowns like o’nyong-nyong, an African virus that causes debilitating joint pain, to Rift Valley fever, a common livestock illness.
That’s just the viruses we know. A project called PREDICT, funded by the US Agency for International Development, is looking for others. In places, mostly tropical, where humans and wild mammals interact, the project screens people, their food and their rodent, bat and primate neighbours, looking for genetic sequences of viruses in families known to spawn human pathogens. They have found 984 viruses, 815 of them new to science. In the process, they have mapped hotspots of viral diversity and trained and equipped local labs to test for viruses and watch for disease.
Predicting risk
But which of these viruses should we focus on? Some are obvious, such as a Chinese virus closely related to SARS but different enough that prototype SARS vaccines won’t work against it. Others might be identified using a clue discovered by Kevin Olival of the EcoHealth Alliance, who works with PREDICT.
He has statistically analysed all the available data on the flavivirus family, a troublesome lot carried by mosquitoes and ticks that includes yellow fever, Zika, dengue and West Nile. Last November, he reported that the more species a flavivirus regularly infects, the more likely it is to infect humans as well. That makes the riskiest flaviviruses a clutch of virtual unknowns: Usutu – a bird-borne virus invading Europe – Ilheus, louping ill, Wesselsbron and Tyuleniy.
The Global Virome Project wants to go further in learning about the enemy, genetically sequencing and mapping most of the estimated half-million so-far undiscovered viruses in families we know can infect humans. It reckons it will need $3.4 billion to do that over the next decade, and this year it will start canvassing for funds. The hope is that knowing what viral diversity exists and where could provide unexpected insights and spur investment in disease control.
2 Arm yourself
Once we know what we are fighting, we have to arm ourselves. Finding weapons won’t be easy, though. The vaccines that defeated so many infectious diseases in the 20th century were mostly made by government-owned firms that didn’t have to turn a profit and produced what was needed as a “public good”. In the 1980s, everything was privatised. That was good for spurring profitable medicines for chronic conditions. But much medical innovation is now done by small, start-up biotech firms, which can’t afford to shepherd their products through the “valley of death” – the long, expensive process of testing for safety and efficacy, and establishing manufacturing processes and formulations for licensing. Only big pharma companies have the know-how and the $1 billion or so needed to bring a new vaccine to market. But vaccines for common diseases offer little profit; those against a virus that might or might not go epidemic are a commercial non-starter.
There have been efforts to bring public good back in. Since the 1990s, new treatments for diseases of poverty, like the meningococcal vaccine for Africa, were developed by public-private partnerships between big pharma, governments and large philanthropies like the Bill & Melinda Gates Foundation. “But the momentum fell,” says Farrar. In 2013, government and private research on “neglected” emerging diseases amounted to only 1.6 per cent of the $195 billion spent on health R&D.; Of that, only a fifth was private.
Now, because of Ebola, the momentum may be back. Last May, the World Health Organization set out an “R&D; blueprint for action to prevent epidemics“, which aims to bring all parties together to develop responses before the next plague strikes. Committees are being set up to look for solutions to problems that emerged during the Ebola outbreak, from agreed protocols for quickly testing and licensing experimental drugs and vaccines, to liability insurance for using experimental products, to contracts ensuring information and biological samples are shared.
But the most important goal is to accelerate R&D; on nine priority pathogens (see “The nine viruses of the apocalypse“). Using an approach pioneered for malaria vaccines, the WHO will find out what research is being done, get participants talking and push progress towards vaccines, drugs and diagnostic tests. Any products must be affordable. That means their prices will be “delinked” from the cost of developing them, by making sure companies are recompensed in other ways. So far no one knows how that will work, but it is already being discussed for new antibiotics.
The WHO is not alone in trying to encourage the forging of weapons. In January, the Coalition for Epidemic Preparedness Innovations (CEPI) was launched at the World Economic Forum in Davos, Switzerland, to help get experimental vaccines through the “valley of death”. CEPI, which is backed by Norway, India, the Gates Foundation and the Wellcome Trust, has commitments of $540 million and, say organisers, is “on track” to get $1 billion for the next five years. By then it hopes to have vaccines against Nipah, MERS and Lassa viruses tested for safety and effectiveness in phase II trials. It even wants to have small stockpiles of the promising vaccines for fast response to outbreaks.
However, no one can afford phase III trials on larger numbers of people. And no one can test whether a vaccine works until there is an outbreak. Those tests may have to be done in a hurry once an epidemic starts.
3 Be ready to act – fast
airport scanner
Going global: international flights spread pathogens
Ognen Teofilovski / Reuters
With potential mass killers identified, and drugs in hand, we will be on the right track. But we must also be ready to act fast on a large scale. Paradoxically, that means getting more familiar with what is normal, so we can spot ominous changes.
One problem is that contagion is exponential: case numbers rise very slowly at first, then sky-rocket. “First people complain that you are putting too much effort into a small problem. Later they say you were too slow,” says Sylvie Briand, head of the pandemics department at the WHO. To better predict which outbreaks might take off, the WHO now has teams looking at the use of “big data”, such as combining existing data sets on climate, vaccination and population immunity. It is also setting up networks of social scientists and anthropologists to explore ways to improve communications among people swept up in plagues – a major roadblock to rapid response during the Ebola outbreak. The first and fundamental problem there, however, was surveillance: no one spotted the first few cases of Ebola before it spread widely.
“To get ready for the big one, we need health workers close to the entire population, everywhere, who know where to go if something funny is going on – then labs to test samples, and response teams,” says Seth Berkley, head of GAVI, a global alliance that helps poor countries get routine vaccines. Under a 2005 treaty called the International Health Regulations, all 192 WHO member states must set up enough surveillance to tell the WHO about any outbreak that is serious, unusual or could trigger international travel or trade restrictions. However, not one world region, even Europe, has done everything the treaty requires. Africa, home of many worrying viruses, has done least.
An international collaboration called the Global Health Security Agenda is trying to help countries fill the gaps – and Ebola has scared many into listening. “There has been a change of mindset,” says Briand: watching existing health risks more closely will help countries spot new ones.
Emergency responders
In addition, the WHO, which has always been a technical agency, setting policies by slow consensus, has reinvented itself to respond faster in an emergency. Instead of independent offices in different countries spotting emergencies – or not – according to their own criteria, the WHO now has dedicated staff worldwide who can do standardised assessments of unusual events, deploy emergency teams within 72 hours and scale up quickly. To aid coordination, they are answerable to the head office in Geneva, a first for the WHO.
lab
Even supplying equipment in a crisis will be a challenge
Roberto Caccuri/contrasto/eyevine
The agency is also working with the World Food Programme to set up global supply chains for equipment such as masks and syringes. This year it will launch an online course to train emergency responders. And it is working with the Inter-Agency Standing Committee, a Geneva-based body that coordinates the world’s emergency responses to war and natural disasters, which last year expanded its remit to epidemics.
But, no matter how fast you detect outbreaks, or how many drugs or vaccines you invent, you still face the problem of producing and deploying enough of them to make a difference. “You can’t build a vaccine factory and only switch it on in an emergency,” says Martin Friede at the WHO. Like standing armies, production lines and staff need honing and updating.
Plagued by plagues
A possible solution for limited manufacturing capacity comes from ongoing efforts to control flu – one pandemic we know for sure will come. The flu vaccine is made of a standard, benign flu virus with two new proteins from whatever strain is circulating that year stuck onto it to induce immunity to that strain. The vaccine changes every year, but doesn’t need new plants or regulatory approval as the package is well tested. “We can produce safety-tested vectors at scale, then drop in antigens of interest if a new disease emerges,” says Berkley. “That way, you can build vaccine capacity for a pathogen you don’t even know.”
That isn’t happening yet. Nor is it clear if the WHO will get enough funds to continue any of this work, especially with a new US president who has opposed UN funding. “The really big problem is appreciating what is at stake,” says Berkley. He says a pandemic is an “evolutionary certainty”. “If people understood the risk, they would want to be sure systems are in place to deal with it. The costs of doing that are trivial compared to the cost of ignoring it.”
We have been jolted out of our complacency, but there’s still a lot to be done. “With Ebola the world recognised that the largest unmanaged risk to the global economy and security is infectious hazards,” says Bruce Aylward, assistant director-general at the WHO. “Are we prepared for pandemics? Definitely not! Are we more prepared? Definitely.”
The nine viruses of the apocalypse
These are the diseases the World Health Organization thinks we should find remedies for, fast. The first six are its highest priority.
Lassa fever
Lassa virus
James Cavallini/SPL
This West African virus, carried by the common Natal multimammate rat, infects 300,000 people a year. Most have no symptoms, but it can cause diarrhoea and vomiting, then internal fluid accumulation, bleeding from orifices, shock, seizure and coma. It kills some 5000 people annually. Initial symptoms resemble other local diseases, making diagnosis tricky – one reason West Africa was slow to spot Ebola.
Nipah
Nipah virus
Science Source/SPL
This bat virus started killing people in 1999 in Malaysia after pig farms were built near fruit bats, which dropped half-eaten fruit into pigsties. People get it from pigs and bats, but it can also spread between humans. Nipah breaks out sporadically in and around densely populated Bangladesh, causes inflammation of the brain and has a high fatality rate.
Rift Valley fever
Rift valley fever
F. A. Murphy; J. Dalrymple/SPL
Widespread across Africa, this virus invaded the Arabian Peninsula in 2000, and could go further. It mainly infects cattle and is spread by mosquitoes; people can get it from mosquito bites or by eating infected beef. Symptoms are usually mild but it can cause haemorrhagic fever, which kills in half of cases.
SARS, MERS and emerging coronaviruses
SARS virus
A. Dowsett, Public Health England/SPL
These related bat viruses infect a range of mammals and have already emerged in humans twice, resulting in severe pneumonia: SARS in 2003 and MERS in 2014. Both spread from human to human.
Crimean-Congo haemorrhagic fever
Found across Africa, Asia and south-east Europe, the virus is invading new territory as its tick hosts capitalise on global warming. It appeared in western Europe in 2010. Infected people generally have a mild fever but some strains cause severe haemorrhagic disease, with bleeding internally and from orifices, from which 30 per cent of people die.
Chikungunya
A virus spread by Aedes mosquitoes between monkeys and small mammals in East Africa, Chikungunya started causing large epidemics around 2000 and exploded into Asia in 2005, after mutations made it better adapted to a new mosquito host. In 2014, it invaded the Americas and has occurred in Europe. It rarely kills but causes debilitating joint pains, which can persist for months.
Zika
A monkey virus that has infected humans in Africa and Asia for decades, Zika suddenly entered the Americas in 2013. In 2015, it was linked to a wave of severe birth defects including microcephaly. Companies are already working on vaccines but the WHO wants extra research into the virus’s effects on fetal brains.
Severe fever with thrombocytopenia syndrome
Flies under the radar – possibly because of its name. The virus, discovered in 2011, can cause fever and multi-organ failure, killing 12 per cent of people it infects. It has been found in east Asia, seems to be carried by farm animals, and is spread by ticks. A nearly identical virus, called heartland, has turned up in the US.
Novel agent
Given the rate at which previously unknown or obscure infections have suddenly emerged in humans and other animals, the WHO is leaving a slot on its list for a germ we don’t yet know. Research here may include looking for agents that might explode.
Money matters
As global economies become more interconnected, contagious diseases and their knock-on effects spread more rapidly. “Nowadays the biggest risk from epidemics is economic,” says Ramanan Laxminarayan of Princeton University. The 2003 SARS epidemic killed 800 people, for example, but cost the world $54 billion in quarantine measures and lost trade and travel. The World Bank estimates that a flu pandemic as bad as the one in 1918 would lop 5 per cent off world GDP and cause an $8 trillion recession. The faster we respond to an epidemic, the less expensive it will be. So we must be prepared – and that costs. Who will pay?
One answer may be novel funding mechanisms. Last May, the World Bank launched something new: plague insurance. Rich countries are at risk from epidemics that start in poor countries. So under the Pandemic Emergency Financing Facility they can buy insurance against severe flu, coronaviruses like SARS or MERS, filoviruses like Ebola, and diseases that pass between animals and humans like Lassa. Premiums are based on risk, calculated for the bank by the epidemiological modelling company Metabiota. If one of these diseases strikes a poor country, money to contain it can be released quickly from the insurance pot. The bank also sells “catastrophe” bonds to fund response to a wider range of epidemics.
How you can reduce the risk of a pandemic
In our increasingly crowded, urban, globalised world, a virus will eventually get out of control. There are things we can all do to reduce the risks.
Bear witness: Inform yourself and do what you can to spread awareness of the risks, and of the responses being devised that desperately need support. Politicians control purses, so get tweeting.
Stand up to denialists: Some will say warnings about pandemics are a hoax, because SARS/bird flu/swine flu was supposed to kill us all and didn’t. Here’s your riposte: a lot of people worked hard to keep SARS contained; bird flu hasn’t gone rogue yet but it’s a few mutations away; swine flu did kill and the next flu could kill far more.
Prepare: You needn’t be a survivalist to prepare for the panic and disorder likely to attend a pandemic. Most countries have guidelines that recommend stocking a few weeks’ worth of water, food, medicines, flashlight batteries and such. Learn about the best ways to avoid people who might be contagious. If you run a business, have a continuity plan. If you are a public official, check whether your administration has a pandemic plan. If not, check out the WHO’s guidelines. If you speak for a health body or organisation, learn about communications in a pandemic because mistakes can be deadly. Hint: trust people with the truth.
Keep watch: Countries don’t like to admit they have infectious diseases: it’s bad for business. The ProMed global reporting site revealed SARS and MERS before the governments involved did. Now it has helped launch Epicore. Medical and veterinary workers sign up to it, then when ProMed gets wind of something it asks them what’s happening. Replies appear on a web platform that can be set to partial or total confidentiality. Wherever you are, if you meet the criteria, sign up to Epicore. You could be the first to spot something amiss.
This article appeared in print under the headline “The coming plague”
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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
Article toolsRights & Permissions
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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Malaria is getting bigger and badder — and we’re not ready for it.
Over the past 15 years the number of annual deaths due to malaria has plummeted by about 400,000, according to the World Health Organization. Scientists also estimate that more than 660 million cases of the disease were averted thanks to scaling up of prevention and treatment.
Malaria is getting bigger and badder — and we’re not ready for it
By Robert Gebelhoff February 3
A female Anopheles stephensi mosquito feeds on human skin. (James Gathany/Centers for Disease Control and Prevention via Associated Press)
Over the past 15 years the number of annual deaths due to malaria has plummeted by about 400,000, according to the World Health Organization. Scientists also estimate that more than 660 million cases of the disease were averted thanks to scaling up of prevention and treatment.
But that progress is in jeopardy. Thanks to decades of using insecticides and drugs to stave of the mosquito-borne disease, malaria has slowly been evolving to get around our offenses. Without any effective vaccine in place, we’re in desperate need of new tools to fight it.
“We’re really close to having a truly untreatable malaria,” said Christopher Plowe, a microbiologist at the University of Maryland School of Medicine and an expert in malaria resistance.
[Here’s why mobile money is dramatically reducing poverty in Kenya]
Plowe and other scientists have been warning about the impending resistance crisis for years, but it’s becoming increasingly clear that the situation has only gotten worse, both in terms of prevention and treatment.
A group of researchers published a paper earlier this week detailing the emergence of malaria parasites in western Cambodia, southern Laos and northeastern Thailand that are resistant to two commonly used treatment drugs, artemisinin and its partner drug piperaquine. What’s more, the parasites appear to be genetically mutated in such a way that makes them more capable of moving from one person to another.
Nicholas White, one of the study’s authors and a professor at Mahidol and Oxford universities, attached a grim statement to the paper: “The spread and emergence of drug resistant malaria parasites across Asia into Africa has occurred before. Last time it killed millions.”
At the same time, mosquitoes have also slowly become resistant to the insecticides commonly used in bed nets throughout the developing world. One study published this week, which examined mosquitoes across the continent of Africa, warns of widespread resistance to pyrethroids — the primary insecticide used in malaria prevention. Scientists believe that pyrethroids have prevented the vast majority of malaria cases over the past few decades, so losing that tool would do serious harm to our progress in Africa.
Failures on both of these fronts in the war against malaria control mean that without some form of proactive strategy to stem the problem, our global success over malaria will likely falter.
There are some potentially powerful tools in development that could end up being game-changers. In Brazil, for example, scientists fighting off the Zika virus have tested the use of genetically modified mosquitoes, adding a “self-destruct gene” in the insect that causes new generations to die before reaching adulthood. The results were fairly encouraging, but some scientists warn that this might only create an ecological hole for other disease-carrying mosquito species to fill.
[Microcredit isn’t dead]
On the drug side, researchers have been testing vaccines, and while there is one vaccine approved in Europe, clinical tests show that it only reduces instances of the disease in infants by about a third. Other vaccines are being tested in clinical trials, but there’s no guarantee that they’ll be approved any time soon or that they will be any more effective than what we already have.
The problem is that malaria isn’t caused by a simple virus or bacteria; it’s the result of a much more complex organism living in the saliva of mosquitoes. We’ve been looking for an effective vaccine for the disease since the 1930s, and so far we haven’t had much luck. This is why experts remain unwilling to hold their breath that a game-changer will enter the scene. Right now, their focus is on maximizing the impact of the drugs they have on hand.
It’s hard to understate the destructive power of malaria. Some scientists estimate that half of all people who ever lived were killed by the disease, and the Centers for Disease Control and Prevention estimates that the direct cost of the disease alone — which includes treatment and premature death — comes out to $12 billion a year.
“Countries have made progress, but the danger is if we let up on that effort, [malaria] will come roaring back,” Plowe said. “The drugs that are failing can be replaced with other drugs, but the bench does not go deep.”
Resistant malaria needs to be a high priority for the new administration and governments in the developing world. With the proper resources and attention, we might be able to stave off catastrophe.
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