A 41-year-old man in New Hampshire died last week after contracting a rare mosquito-borne illness called eastern equine encephalitis virus, also known as EEE or “triple E”. It was New Hampshire’s first human case of the disease in a decade. Four other human EEE infections have been reported this year in Wisconsin, New Jersey, Massachusetts, and Vermont. 

Though this outbreak is small and triple E does not pose a risk to most people living in the United States, public health officials and researchers alike are concerned about the threat the deadly virus poses to the public, both this year and in future summers. There is no known cure for the disease, which can cause severe flu-like symptoms and seizures in humans 4 to 10 days after exposure and kills between 30 and 40 percent of the people it infects. Half of the people who survive a triple E infection are left with permanent neurological damage. Because of EEE’s high mortality rate, state officials have begun spraying insecticide in Massachusetts, where 10 communities have been designated “critical” or “high risk” for triple E. Towns in the state shuttered their parks from dusk to dawn and warned people to stay inside after 6 p.m., when mosquitoes are most active. 

Like West Nile virus, another mosquito-borne illness that poses a risk to people in the U.S. every summer, triple E is constrained by environmental factors that are changing rapidly as the planet warms. That’s because mosquitoes thrive in the hotter, wetter conditions that climate change is producing.

“We have seen a resurgence of activity with eastern equine encephalitis virus over the course of the past 10 or so years,” said Theodore G. Andreadis, a researcher who studied mosquito-borne diseases at the Connecticut Agricultural Experiment Station, a state government research and public outreach outfit, for 35 years. “And we’ve seen an advancement into more northern regions where it had previously not been detected.” Researchers don’t know what causes the virus to surge and abate, but Andreadis said it’s clear that climate change is one of the factors spurring its spread, particularly into new regions. 

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The first triple E outbreak on record occurred in Massachusetts in the 1830s in horses — the reason one of the three Es stands for “equine.” It wasn’t until a full century later, in 1934, that mosquitoes were incriminated as potential vectors for the disease. The first recorded human cases of the disease also occurred in Massachusetts four years later, in 1938. There were 38 human cases in the state that year; 25 of them were fatal. Since then, human cases have mostly been registered in Gulf Coast states and, increasingly, the Northeast. From 1964 to 2002, in the Northeast, there was less than one case of the disease per year. From 2003 to 2019, the average in the region increased to between 4 and 5 cases per year.

The disease is spread by two types of mosquito. The first is a species called Culiseta melanura, or the black-tailed mosquito. This mosquito tends to live in hardwood bogs and feeds on birds like robins, herons, and wrens, spreading the virus among them. But the melanura mosquito doesn’t often bite mammals. A different mosquito species, Coquillettidia perturbans, is primarily responsible for most of the human cases of the disease reported in the U.S. The perturbans mosquito picks up the EEE virus when it feeds on birds and then infects the humans and horses that it bites. Toward the end of the summer, when mosquitoes have reached their peak numbers and start jostling for any available blood meal, human cases start cropping up. 

Andreadis, who published a historical retrospective on the progression of triple E in the northeastern U.S. in 2021, said climate change has emerged as a major driver of the disease. 

“We’ve got milder winters, we’ve got warmer summers, and we’ve got extremes in both precipitation and drought,” he said. “The impact that this has on mosquito populations is probably quite profound.” 

Warmer global average temperatures generally produce more mosquitoes, no matter the species. 

Studies have shown that warmer air temperatures up to a certain threshold, around 90 degrees Fahrenheit, shorten the amount of time it takes for C. melanura eggs to hatch. Higher temperatures in the spring and fall extend the number of days mosquitoes have to breed and feed. And they’ll feed more times in a summer season if it’s warmer — mosquitoes are ectothermic, meaning their metabolism speeds up in higher temperatures. 

Rainfall, too, plays a role in mosquito breeding and activity, since mosquito eggs need water to hatch. A warmer atmosphere holds more moisture, which means that even small rainfall events dump more water today than they would have last century. The more standing water there is in roadside ditches, abandoned car tires, ponds, bogs, and potholes, the more opportunities mosquitoes have to breed. And warmer water decreases the incubation period for C. melanura eggs, leading one study to conclude that warmer-than-average water temperatures “increase the probability for amplification of EEE.” 

Climate change isn’t the only factor encouraging the spread of disease vectors like mosquitoes. The slow reforestation of areas that were clear cut for industry and agriculture many decades ago is creating new habitat for insects. At the same time, developers are building new homes in wooded or half-wooded zones in ever larger numbers, putting humans in closer proximity to the natural world and the bugs that live in it. 

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On an individual level, the best way to stay safe from EEE and other mosquito-borne diseases is to prevent bites: Wear long sleeves and pants at dusk and dawn, when mosquitoes are most prone to biting, and regularly apply an effective mosquito spray. But there are also steps that local health departments can take to safeguard public health, like testing pools of water for mosquito larvae and conducting public awareness and insecticide spraying campaigns when triple E is detected. Massachusetts is an example of a state that has been proactive about testing mosquitoes for triple E in recent summers. 

The most effective way to protect people from this disease would be to develop a vaccine against it. A vaccine already exists for horses, but there is little incentive for vaccine manufacturers to develop a preventative for triple E in humans because the illness is so rare.  

“Although EEE is not yet a global health emergency, the recent uptick in cases has highlighted our lack of preparedness for unexpected infectious disease outbreaks,” a group of biologists wrote last year in the open-access scientific journal Frontiers. “It would be wise to follow proactive active control measures and increase vigilance in the face of these threats.”

This story was originally published by Grist with the headline How climate change is expanding the reach of a rare and deadly mosquito-borne illness on Aug 30, 2024.

This post was originally published on Grist.

Roger Casupang was working in a coastal clinic on the north side of Papua New Guinea, an island nation of 9 million in the southwestern Pacific Ocean, when a pregnant woman burst into his facility. She was in labor, moments away from delivering twins. She also had a severe case of malaria, a life-threatening mosquito-borne illness common in tropical countries.

Casupang, an obstetrician, quickly took stock of the situation. When the parent is healthy, a twin pregnancy is twice as risky as a single pregnancy. Meanwhile, severe malaria kills nearly half of the people who develop it during pregnancy. The woman was exhausted and delirious. Because many of his patients walked for days to get medical care for standard ailments, Casupang didn’t know which province she had come from or how long she had been traveling before she reached his clinic. 

What he did know was that the woman had arrived just in time. “She was actually pushing when she came in,” he said. 

Casupang, who was born in one of Papua New Guinea’s highland provinces and had been practicing medicine on the island for the better part of a decade at the time, had seen pregnant women die in less dire circumstances. Against all odds, with limited medical resources and medicines at their disposal, Casupang and the other medical professionals at the clinic were able to deliver the twins safely. Both babies weighed less than three pounds each, a consequence of their mother’s raging infection. The twins were moved to the nursery while Casupang and his fellow physicians worked to stabilize the mother. She was reunited with her babies after 10 days of intensive care. “If this case had presented in a remote facility,” Casupang said, “the narrative would have been very different.” 

Casupang’s patient was lucky to survive — but she also benefited from geography. On the coast, doctors see lots of patients with malaria, and many of those patients carry antibodies that protect them from severe infection. 

But malaria is on the move. 

Temperatures are rising around the world but particularly in countries where the disease is already present. That warming coaxes mosquitoes toward higher elevations, even as temperatures have historically been too cold for the insects to thrive. In these high-altitude areas, mosquitoes are feeding on people who have never had malaria before — and who are much more susceptible to deadly infections.

“When malaria hits new populations that are naive, you tend to get these explosive epidemics that are severe because people don’t have any existing immunity,” said Sadie Ryan, an associate professor of medical geography at the University of Florida. 

Pregnant people living in highland regions who have never had malaria before are worst-positioned to survive the bite of an infected mosquito. The very act of becoming pregnant creates a potentially deadly vulnerability to malaria. The placenta, the new organ that forms to nourish the fetus, presents new receptors for the disease to bind to. 

Pregnant women are three times more likely to develop severe malaria compared to nonpregnant women. For people who can become pregnant, the climate-driven upward movement of malaria mosquitoes poses nothing less than an existential threat.

“In Western countries, especially where malaria is not endemic, there is this perception that malaria has been around for so long that we already know how to deal with it,” said Deekshita Ramanarayanan, who works on maternal health at the nonpartisan research organization the Wilson Center. 

But that was never the case, and the perception is especially flawed now, as climate change threatens to rewrite the malaria-control playbook. “Pregnant people are hit with this double risk factor of climate change and the risks of contracting malaria during pregnancy,” Ramanarayanan said. 

Hundreds of millions of people get malaria every year, and an estimated 2.7 million die from it, mostly in tropical and subtropical regions. In 2022, 94 percent of global malaria cases occurred in sub-Saharan Africa. High rates of the disease are also found in Central America and the Caribbean, South America, Southeast Asia, and the western Pacific. Papua New Guinea registered over 400,000 new cases in 2022. That same year the country accounted for 90 percent of the malaria cases in the western Pacific.  

Malaria is carried by dozens of species of Anopheles mosquitoes, also known as marsh or nail mosquitoes. Anopheles mosquitoes carry a parasite called Plasmodium — the single-cell genus that causes malaria in birds, reptiles, and mammals like humans. 

When the bite of an Anopheles mosquito introduces Plasmodium into the human bloodstream, the parasites travel to the liver, where they lurk undetectably and mature for a period ranging from weeks to a year. Once the parasites reach maturity, they venture out into the bloodstream and infect red blood cells. The host often experiences symptoms at this stage of the infection — fever, chills, nausea, and general, flu-like discomfort. 

The earlier a malaria infection is caught, the better the chances that antimalarial medications can help prevent the development of severe malaria, when the disease spreads to critical organs in the body. 

Pregnancy primes the body for infection. 

The immune system, when it is functioning properly, engages an arsenal of weapons to ward off bacteria, viruses, and other pathogens. But pregnancy acts like an immunosuppressant, telling the defense system to stand down in order to ensure the body does not inadvertently reject the growing baby. “Your immune system is, on purpose, dialed back so that you can tolerate the fact that you have this fetus inside of you,” said Marya Zlatnik, an obstetrician and gynecologist at University of California, San Francisco Medical Center.

Then there’s the added strain of supplying the baby with enough nutrients, vitamins, and minerals. The body must work overtime to provide for the metabolic needs of two. This factor, exacerbated by poverty, malnutrition, and subpar medical infrastructure in countries where malaria is commonly found, poses enormous challenges to maternal and fetal health. A malaria infection on top of those existing vulnerabilities introduces another, even more challenging set of obstacles.

The disease can produce severe maternal anemia, iron deficiency, or it can spread to the kidneys and the lungs and cause a condition known as blackwater fever. The disorder makes patients jaundiced, feverish, and dangerously low on vitamins crucial for a healthy pregnancy. 

“It’s pretty much synonymous with death for many patients up in the rural areas,” Casupang said. Research shows that malaria may be a factor in a quarter of all maternal deaths in the countries where the disease is endemic. 

Plasmodium parasites have spikes on them, similar to the now-infamous coronavirus spike proteins, that make them sticky and prone to clogging up organs. If Plasmodium travel to the placenta, the parasites bind to placental receptors and cause portions of the placenta to die off. “It changes the architecture of the placenta and the ways nutrients and oxygen are exchanged with the fetus,” said Courtney Murdock, an associate professor at Cornell University’s department of entomology. The placental clots interfere with fetal growth, and they’re one of the reasons why a pregnant woman is between three and four times more likely to miscarry if she has a malaria infection, and why babies born to mothers sick with malaria come out of the womb malnourished and underweight. 

“You see the placenta start to fail,” Casupang said. Fetal mortality is closely tied to how much of the placenta becomes oxygen deprived. “The babies come out with very low birth weights,” he said. If the placental clots are extensive, “they usually die.” 

In 2020, approximately 122 million pregnancies — about half of all pregnancies worldwide that year — occurred in areas where people were at risk of contracting malaria. A 2023 study estimated that 16 million of these pregnancies ended in miscarriage, and 1.4 million in stillbirth. 

Researchers don’t know exactly how many of those miscarriages and stillbirths occurred in individuals who were bitten by malaria-infected mosquitoes. 

However, the World Health Organization estimates that approximately 35 percent of pregnant people in African countries with moderate to high malaria transmission were exposed to the disease during pregnancy in 2022. A widespread lack of health data in poor countries makes it nearly impossible to know how many of those infections resulted in maternal, fetal, or infant death. “Unfortunately, it is only safe to say that we do not have good morbidity estimates at this point,” said Feiko ter Kuile, chair in tropical epidemiology at the Liverpool School of Tropical Medicine.

Researchers have said that out of all the high-impact infectious diseases — including Ebola, mpox (formerly known as monkeypox), and MERS — malaria is the “most sensitive to the relationship of human populations to their environment.” In Papua New Guinea, the coastal zones that sit near or at sea level have long had environmental conditions that foster the development and spread of the Anopheles mosquito. Cases of malaria topped 1.5 million in 2020, and the vast majority occurred in the nation’s lowlands. 

At 4,000 feet or more above sea level, where some 40 percent of the Papua New Guinean population lives, temperatures have historically been too cold for Anopheles mosquitoes to thrive year-round. There have been seasonal outbreaks of malaria in those zones, but the background hum of malaria present in the lowlands largely disappears above the 4,000 feet mark. At 5,200 feet above sea level, periodic freezes kill mosquitoes and prevent them from establishing widely, making malaria infections there very rare.

But climate change is expanding the areas where Anopheles mosquitoes and the Plasmodium they carry flourish by fostering warmer, wetter environments. Mosquitoes thrive in the aftermath of big storms, when the insects have ample opportunity to breed in standing pools of water. 

At the same time, higher-than-average temperatures almost everywhere in the world mark the beginning of a new chapter in humanity’s long struggle to contain mosquitoes and the diseases they carry. Anopheles mosquitoes grow into adults more quickly in warmer weather, and longer warm seasons allow them to breed faster and stay active longer. 

This poses problems in areas where Anopheles mosquitoes are already prevalent, and in regions the insects are poised to infiltrate. The mountainous regions of the world — the Himalayas, the Andes, the East African highlands — are thawing as average global temperatures climb. What used to be an inhospitable habitat is becoming fertile ground for malaria transmission. 

Like their mosquito hosts, Plasmodium parasites are sensitive to temperature. The two most common strains, Plasmodium falciparum and Plasmodium vivax, like temperatures in the range of 56 to 95 degrees Fahrenheit. The warmer the weather, the more quickly the parasites are able to reach their infectious stage. A study that examined temperatures suitable to Plasmodium in the western Himalaya mountains predicted that, by 2040, the mountain range’s high-elevation sites — 8,500 feet above sea level — “will have a temperature range conducive for malaria transmission.”  

There’s little data on the rate at which Anopheles mosquitoes and the parasites they carry are moving upward in Papua New Guinea, but research shows temperatures across Papua New Guinea were, on average, just under 1 degree Celsius (1.8 degrees F) warmer between 2000 and 2017 than they were a century prior. A report conducted by the World Bank Group noted that this temperature rise “has been fastest in the minimum temperatures,” meaning climate change jeopardizes the overnight low temperatures that are so essential to mosquito control. Anecdotally, doctors and nurses working in the country’s colder regions say they have seen a familiar pattern begin to change. 

Stella Silihtau works in the emergency department at the Eastern Highlands Provincial Health Authority in Goroka, a town of 20,000 that sits at 5,200 feet above sea level on a major road that connects the scattered highland cities and towns to the communities along the coast. Silihtau and her colleagues are no strangers to malaria. Hundreds of people in Goroka and surrounding highland towns grow cash crops like coffee, tea, rubber, and sugarcane and ferry them down to the coast every week to sell to plantations and community boards. The highland dwellers are bitten by mosquitoes at lower elevations, and end up at the hospital where Silihtau works weeks later, sick with malaria. Over the past year, she’s seen unusual cases starting to crop up.

“We’ve been seeing a lot of patients that are coming in with malaria,” said Silihtau, who grew up in the lowlands. Many of these cases have been in people who have not traveled at all. “We’ve seen mild cases, severe cases, they go into psychosis,” she said.

Silihtau and her colleagues don’t have the time or staff to keep close track of how many locally acquired malaria cases have been treated at the hospital over the past year. But Silihtau estimates that when she first started working at the hospital in Goroka two years ago, she saw one case per eight-hour shift, or none at all. Now, she sees between two and three cases of malaria per shift, some of them in individuals who have not traveled outside the boundaries of Papua New Guinea’s highland zones. “It’s a new trend,” Silihtau said. 

The new dangers that the upward movement of malaria mosquitoes pose to pregnant people are obfuscated by positive signals in malaria cases globally. 

Global malaria deaths plummeted 36 percent between 2010 and 2020, the dive driven by wider implementation of the standard, relatively low-cost treatments that research shows are incredibly effective at preventing severe infections: insecticide-treated mosquito nets, antimalarial drugs, and malaria tests. 

This promising trend stalled in 2022, when there were an estimated 249 million cases of malaria globally — up 5 million from 2021. Much of the increase can be attributed to the COVID-19 pandemic, which slowed various global infectious disease control efforts as health care systems tried to contain an entirely new threat. Funding for malaria control is also falling short. Countries spent a total of $4.1 billion on malaria in 2022, nowhere near the $7.8 billion in funding the World Health Organization says is necessary annually to reduce the global health burden of the disease 90 percent by 2030. 

Meanwhile, cases have been rising in step with the spread of a mosquito called Anopheles stephensi, a species that can carry two different strains of Plasmodium and, unlike the rest of its Anopheles brethren, thrives in urban environments. Efforts to control malaria in both urban and rural settings are stymied by the quickening pace and severity of extreme weather events, which scramble vaccination and mosquito net distribution campaigns, shutter health clinics, and interrupt medical supply chains. Record-breaking storms, which destroy homes and public infrastructure and create thousands of internal migrants, force governments in developing countries to choose where to allocate limited funding. Infectious disease control programs are often the first to go. 

The world’s slowly warming highland regions are one small thread in the web of factors influencing the prevalence of malaria. But because of the lack of immunity among populations in upper elevations, the movement of malaria into these zones poses a unique threat to pregnant people — one that may grow to constitute a disproportionate fraction of the overall impact of malaria as climate change continues to worsen. 

“Pregnant women are going to be a high-risk population in highland areas,” said Chandy C. John, a professor and researcher at Indiana University School of Medicine who has conducted malaria research in Kenya and Uganda for 20 years. John and his colleagues are in the process of analyzing their two decades of health data to try to tease out the potential effects of climate on malaria cases. “What are we seeing in terms of rainfall and temperature and how they relate to risk of malaria over time in these areas?” he asked. His study will add to the small but growing body of research on how temperature shifts in high elevations contribute to the prevalence of malaria.

Controlling and even eradicating malaria isn’t just possible; it has already been done. Dozens of countries have banished the disease; Cabo Verde recently became the third African country to be certified as malaria-free. “Malaria is such a complex disease,” said Jennifer Gardy, deputy director for malaria surveillance, data, and epidemiology at the Bill and Melinda Gates Foundation, “but that complexity is kind of beautiful because it means we’ve got so many different intervention points.” 

In addition to the typical interventions such as mosquito nets, the Papua New Guinea National Department of Health has had some success with medical therapies for people who develop malaria infections while pregnant. Doctors there and in many other malaria-endemic places use intermittent preventive treatment on pregnant women. The antimalarial is administered orally as soon as patients learn they are pregnant and, if taken on regularly, can significantly reduce the chances of severe malaria over the course of gestation. The treatment remains difficult to access in highland regions, as malaria has historically been uncommon there. If governments and hospitals pay attention and get these medicines into places where rising temperatures are changing climatic constraints on mosquitoes, they will save lives. 

The smartest solutions are those that address malaria as a symptom of a wider system of inequity. Papua New Guinea is a “patriarchal society where men get the best treatment,” Casupang, who now works for an international emergency medicine and security company called International SOS, said. “Women are pretty much regarded as commodities.” Most married women must seek permission from their husbands to seek medical care at a facility, and permission is not always granted. Many women are also prevented from seeking medical attention by poverty, by the quality of the roads that connect rural villages to cities, and because they don’t recognize the symptoms of malaria or understand the risks the infection poses to themselves and their unborn children, Casupang said. Just 55 percent of women in Papua New Guinea give birth in a health facility, a partial function of the fact that the country currently has less than a quarter of the medical personnel it needs to care for mothers, babies, and children.

“There are quite a number of factors that will determine the outcome of a mother that has malaria,” Casupang said. “The most important thing is access to a health care facility.” He’s one of many experts who argue that better infrastructure, improvements in education, and the implementation of policies that protect women and girls double as malaria control measures — not just in Papua New Guinea but everywhere poverty creates footholds for infectious diseases to take root and flourish.

“Education, a living wage, sanitation, and all of these other very basic things can do so much for a disease like malaria,” John said. “It’s not a mosquito net or a vaccine, but it can make such a huge difference for the population.”

This story was originally published by Grist with the headline Pregnant in a warming climate: A lethal ‘double risk’ for malaria on May 30, 2024.

This post was originally published on Grist.

Puerto Rico declared a public health emergency this week as cases of dengue fever, a potentially deadly mosquito-borne infection, rise precipitously across the United States territory. In the emergency order, the commonwealth’s department of health said it had recorded 549 cases of the disease this year so far, a 140 percent increase over the same period a year ago. 

The numbers have “surpassed historical records,” health secretary Carlos Mellado López said. 

Puerto Rico’s health department is the latest government agency to mobilize its public health resources in service of controlling and treating large outbreaks of dengue. Bangladesh and Sri Lanka tried to tamp down unprecedented rates of dengue infections in the last year with varying degrees of success. Vast portions of Central and South America are battling months-long, record-breaking dengue crises. Some 5 million cases of the infection were reported worldwide in 2023, and the disease continues to spread. Already, an estimated 3.5 million cases of the infection and 1,000 deaths have been reported across the Americas in 2024 thus far — a rate of infection health officials predict will lead to a record-breaking number of dengue cases this year.

Epidemiologists and climate change researchers warn that warmer temperatures, intensifying storms, and more erratic and frequent rainfall events are contributing to outbreaks of mosquito-borne illnesses around the world. Research shows that over the past two decades, the environment in many regions of the world has become more hospitable to the Aedes genus of mosquito, the insect whose bite spreads dengue to humans. Warmer winters, hotter summers, and particularly milder springs and falls are allowing these mosquitoes to move into new areas and higher elevations that have historically been too harsh for their survival. 

“It’s a complex problem, but climate change, and most importantly consistently increasing temperatures, even in higher elevations,” said Manisha Bhinge, vice president of the Rockefeller Foundation’s health initiative, create “fertile ground for an outbreak.” 

Climate change is not solely responsible for the millions of dengue cases that have occurred since the beginning of 2023. The natural weather phenomenon El Niño, which produces warmer-than-average global temperatures and erratic changes in rainfall patterns across Latin America and other parts of the world, may play a role. Decaying and broken infrastructure, deforestation and urban sprawl, and underinvestment in sewage, water, and sanitation systems all contribute to disease surge by exposing more people to mosquitoes and creating pockets of standing water for the insects to breed in.

Warmer temperatures and extreme weather layered on top of these existing issues compound and exacerbate community vulnerability to dengue and other diseases spread by blood-sucking bugs.

Three in 4 people who get dengue — also known as breakbone fever — exhibit no symptoms, which means the true extent of the viral infection in Puerto Rico and other places is likely much higher than official reports indicate. Those who develop symptoms often report fevers of 104 degrees Fahrenheit or higher, muscle aches, and vomiting. Severe symptoms, such as intense stomach pain; bloody vomit, stool, or gums; and extreme fatigue, typically develop after the fever has passed. Individuals who contract the illness twice, from two different strains, are at a much higher risk of developing severe dengue or dying. The disease cannot be passed directly between people, but a person with dengue in their blood can pass the infection on to a mosquito, which can infect other people. 

Some 340 people have been hospitalized so far this year in Puerto Rico with severe dengue symptoms. More than half of the island’s dengue cases have occurred in San Juan, the territory’s capital, and surrounding municipalities. The Puerto Rican government did not restrict travel into or out of the island, but the department of health said the infection had reached epidemic levels. The emergency order, which will remain in effect for three months, allows the department of health to tap government resources more quickly as it works to detect and control mosquitoes.

Last year, a small but unusual number of locally acquired cases of dengue popped up in California, Texas, and Florida. The risk to people living in the contiguous United States still largely comes from travel to countries where rates of the illness are much higher, though that could change in years to come as temperatures continue to rise.

The Centers for Disease Control and Prevention is currently advising Americans to take precautions against dengue when traveling to many countries in Central and South America, the Caribbean, sub-Saharan Africa, the Middle East, South and Southeast Asia, and the Pacific Islands. In Brazil, which has registered 1.5 million cases of dengue so far this year and recently became the first country in the world to launch a public vaccination campaign against the viral infection, 17 cities declared emergencies. 

There is no one solution to controlling mass outbreaks of dengue. Governments are trying out a multifaceted response that includes public education and vaccine campaigns, spraying mosquito-killing insecticides, draining swamps and puddles of standing water, and deploying new technologies. Brazil, for example, has had some success releasing mosquitoes that have been infected with bacteria that prevents them from carrying dengue in Rio de Janeiro and a handful of other urban centers across the country. Still, the best line of defense for people in affected areas is reducing exposure to mosquitoes by spending time indoors when possible, sleeping in mosquito netting, and frequently applying bug spray. 

This story was originally published by Grist with the headline Puerto Rico declares an emergency as cases of dengue fever spike on Mar 29, 2024.

This post was originally published on Grist.

The Centers for Disease Control and Prevention — the federal agency that monitors diseases and establishes guidelines to protect human health — published a paper last month that shows cases of Lyme disease jumped nearly 70 percent nationwide in 2022. But what looked like an alarming spike in disease was actually the result of smarter disease surveillance that better reflects what’s happening on the ground. 

The CDC revised its Lyme reporting requirements in 2022, making it easier for states with high infection rates to report those cases. The report, the first published analysis of the new data collection guidelines, demonstrates the crucial role efficient surveillance plays in better understanding the scope of infectious disease in the U.S. — and what more must be done to safeguard public health as climate change fosters the proliferation of ticks. 

“Disease surveillance that is interpretable and is standardized is integral to being able to understand how disease frequency is changing, and if it’s changing,” said Kiersten Kugeler, a CDC epidemiologist and lead author of the paper. She noted that climate change will complicate the already difficult task of monitoring and controlling diseases such as Lyme. Cases in some areas will continue rising while declining in others as parts of the U.S. become more amenable, or hostile, to ticks. “It’s not going to be straightforward,” Kugeler said. “It’s going to be incredibly important to have good surveillance to be able to understand how climate is affecting risk of disease.” 

Studies have documented significant shifts in Lyme trends across the country. The illness is caused by the bite of a black-legged tick and causes symptoms that range from flu-like and mild to neurological and debilitating, depending on how quickly the disease is diagnosed. Cases doubled in the three decades between 1990 and 2020. Many researchers, including CDC employees, say climate change is one factor behind that precipitous rise. Environmental changes such as urban sprawl and swelling populations of white-tailed deer, among other drivers, also play a role.

Warmer winter temperatures have coaxed black-legged ticks into regions that have historically been too harsh for the blood-sucking arachnids. Meanwhile, milder spring and fall seasons have given the pests more time to breed. Lyme is a portent of climate-driven diseases to come. But, as it has spread into new areas and infected more people, the CDC has struggled to capture the full impact.

In 2022, the agency redoubled its disease surveillance efforts, with a special emphasis on vector-borne disease. As part of that push, the CDC loosened its Lyme disease reporting requirements in the Northeast, mid-Atlantic, and upper-Midwest, where cases are high. Public health departments in those areas no longer have to track down the clinical details of each positive Lyme test, such as a patient’s symptoms and when they began, and doctors can skip the labor-intensive process of recording and reporting them. Now, a positive laboratory test is sufficient. Eliminating these steps takes the onus off doctors and local public health authorities and puts it on state health departments, which are typically better equipped to handle it. 

“We have a lot of behind-the-scenes data management that’s new with this Lyme disease surveillance system,” Rebecca Osborn, a vector-borne disease epidemiologist at the Wisconsin Department of Health Services. But overall, she said, “it has gotten quite a bit less burdensome.” 

The new system runs the risk of including information on people who no longer show symptoms but are still testing positive for the bacteria, which can linger in the blood for years after the infection has gone. But those cases likely comprise a small fraction of the overall data, the CDC said. In areas where Lyme remains rare, providers must continue reporting clinical information for each case. 

These relatively modest changes to the case definition requirements unearthed 62,551 cases of Lyme nationwide. That’s 1.7 times the annual average reported from 2017 to 2019.

Still, most cases of Lyme disease in the U.S. go unreported. Studies based on health insurance records estimate that roughly 500,000 cases are diagnosed every year. Those reported by states to the CDC in 2022 comprise less than one-fifth of that. Elizabeth Schiffman, an epidemiologist with the Vector Borne Diseases Unit at the Minnesota Department of Health, said figuring out how to capture every case is nearly impossible and perhaps besides the point. 

“No system is ever perfect,” she said, “we’re always going to miss something, we’re always going to count something that probably shouldn’t be counted.” If the CDC could use the data it collects every year under its new system to measure the overall impact of Lyme, Schiffman said, then the number of cases it already knows about may be enough. 

“If what we are able to capture is able to give us an idea of where things are happening, how things are changing, and inform good public health actions, then it could be argued that we don’t need to count every case.” 

The data deficit and lack of standardization among states becomes more of a problem when researchers try to tease out the impacts of climate change on the disease. The CDC argues that in regions where Lyme incidence is still relatively rare, the updated surveillance system doesn’t make sense. Doctors and local health departments in those areas still need to collect clinical information on every potential Lyme patient, because each case is a revealing datapoint rather than a statistic in a larger trend. But the burdensome requirements in low-incidence areas muddy efforts to detect the role of climate change in how black-legged ticks may be migrating, said Richard Ostfeld, a senior scientist at the Cary Institute of Ecosystem Studies who researches tick-borne illnesses. 

The prevalence of Lyme disease typically falls along geographic lines. Counties in the upper Midwest and Northeast report tens of thousands of cases each year, while those in the Southeast and South report hundreds. Although the CDC’s revised reporting guidelines more accurately revealed the extent of Lyme disease in areas with a high prevalence, the implementation of the system over time may obscure growth of the disease elsewhere. The new guidelines “would tend to bias your estimate of geographic trends toward more growth in incidence in northern parts of the country as opposed to southern parts of the country where you’re still being very conservative,” Ostfeld said. “It complicates matters for those trying to understand the role of climate change.”

North Carolina, for example, a state long classified as low-incidence, was among five states with the highest number of Lyme disease-related insurance claims in 2016, according to one analysis. But the disease reporting there, said Noah Johnston, director of the Lyme awareness group Project Lyme, still isn’t where it needs to be. “There’s an expectation that tick populations in North Carolina are not as high as they are in the Northeast,” he said.

The benefits and drawbacks of the CDC’s updated surveillance highlight the difficulties of tracking and controlling infectious diseases under climatic conditions that are rapidly shifting the distribution of disease carriers. Incremental adjustments to the status quo might not be enough to keep up with the growing scale of disease risk. “We’re likely going to see more and more cases of these diseases and more and more diseases that are going to affect not just our population in the U.S., but globally,” said Osborn. “Public health in general needs to become a little more proactive in our responses. We’re still working on that as a field.” 

This story was originally published by Grist with the headline As ticks spread, the US is getting closer to understanding the true extent of Lyme disease on Feb 29, 2024.

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The Environmental Protection Agency released the final version of a much-anticipated rule on Wednesday that tightens restrictions on fine particulate matter — one of the most pervasive and dangerous forms of air pollution. This is the EPA’s first update to its particulate matter standard in more than a decade, and the agency said it expects the new rule to save thousands of American lives every year. 

Fine particulate matter, or PM2.5, is a category of tiny air-borne particles produced by power plants, forest fires, and industrial factories, among other sources. The minuscule bits of matter are roughly 30 times smaller than the width of a human hair and can lodge deep inside human lungs. PM2.5, often referred to as soot, is linked to serious health problems, such as asthma, lung and heart disease, and respiratory symptoms. One in three Americans breathe unhealthy air, and studies have shown that low-income and minority communities across the country, historically clustered near power plants and other industrial infrastructure, bear the brunt of these health effects.

The Biden administration said the new rule —  which ratchets down the existing annual fine particulate matter standard from 12 micrograms of matter per cubic meter of air to 9 micrograms — will prevent an estimated 4,500 premature deaths every year and ultimately yield $46 billion in net health benefits annually. 

The EPA plans to take samples of air across the country starting this year through 2026 to ensure states are compliant with the new rule. It will also tweak its air monitoring network to better capture the air pollution risks that communities living near industrial infrastructure face. Then, states will have to develop plans to meet the EPA’s new requirements within 18 months. 

“This final air quality standard will save lives and make all people healthier, especially within America’s most vulnerable and overburdened communities,” said EPA Administrator Michael Regan. 

The EPA’s announcement on Wednesday was met with immediate pushback from business groups, who challenged the new rule on the grounds that it will raise costs for power plants and factories, and lead to layoffs in the manufacturing sector. Mike Ireland, president of the Portland Cement Association, told the New York Times that the rule “would lead to fewer hours of operation at plants, which would mean layoffs, as well as less American cement and concrete at a time when the country needs more.” The Portland Cement Association and other industry groups will likely try to challenge the standard in court. 

The EPA estimates some 59 counties across the United States — less than 2 percent of the nation’s counties — may be out of compliance with the new standards. The U.S. Chamber of Commerce, an industry lobby group that opposes the new rule, puts the percentage of non-compliant counties at 18 percent. States that don’t meet the new standards will start paying penalties by 2032. 

Some congressional lawmakers were also critical of the tighter restrictions. Senator Bill Cassidy, a Republican from Louisiana, said the rule “incentivizes manufacturing to move their jobs to China away from Louisiana,” and called on Congress to “step in” to prevent the standard from taking effect.

Other groups, meanwhile, argue the rule could have gone further, limiting fine particulate matter to 8 micrograms per cubic meter — the number initially proposed by the EPA’s own Clean Air Scientific Advisory Committee. “While the stronger annual particle pollution standard will mean fewer asthma attacks, heart attacks, strokes, and deaths,” the American Lung Association said in a statement, “it is disappointing that EPA did not follow the strong science-based recommendations of the Clean Air Scientific Advisory Committee.” Studies have shown that virtually no amount of particulate matter is safe for humans.

This story was originally published by Grist with the headline EPA finalizes new standards for deadly particulate matter on Feb 7, 2024.

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Climate change is triggering a global health crisis that may approach the death toll of some of history’s deadliest plagues. Unlike the 1918 flu epidemic or the COVID-19 pandemic, which were caused by the widespread outbreak of one type of bacteria or virus, climate change-fueled illness is a Hydra-headed challenge that erodes human health on multiple distinct fronts. Efforts are underway to tally this risk, and a growing body of research indicates that climate-related health threats, such as cardiovascular, diarrheal, and vector-borne diseases, have already killed millions of people — a count that will grow steeper as warming accelerates. 

A recent report from the World Economic Forum, a non-governmental organization that promotes public-private partnership on global issues, and Oliver Wyman, a consulting firm, projects that rising temperatures will “place immense strain on global healthcare systems” in the coming years. Climate change will cause 14.5 million additional deaths by 2050, the report says, and spur $12.5 trillion in economic losses. Healthcare systems — hospitals, emergency rooms, doctors, and nurses — will also have to provide an extra $1.1 trillion worth of treatment by mid-century because of climate change. 

These challenges will be felt most acutely in the Global South, where healthcare resources are already limited and governments lack the capacity to respond to cascading climate impacts such as worsening floods, heatwaves, and storms. According to the report, central Africa and southern Asia are two regions that are particularly vulnerable to the overlap of intensifying climate health threats and limited resources. 

“Climate change is transforming the landscape of morbidity and mortality,” the report says. “The most vulnerable populations, including women, youth, elderly, lower-income groups, and hard-to-reach communities, will be the most affected by climate-related consequences.”

In total, the report identified six weather events most likely to trigger negative health outcomes: floods, droughts, wildfires, sea-level rise, tropical storms, and heatwaves. The authors examined the direct and indirect effects of each of these events. 

The burden of indirect impacts far outweighed the direct effects. For example, floods can trigger landslides that injure and kill people during or directly after a flood occurs. But the longer-term consequences of flooding kill more people. Floods eat away at coastlines, damage infrastructure, and kill crops, which in turn contribute to the expansion of mosquito habitat, increase moisture and humidity in the air, and fuel food insecurity. Infectious diseases, respiratory illnesses, malnutrition, and mental health issues follow. The report predicts that the greatest health consequences of extreme rainfall and flooding in central Africa and Southeast Asia, two of the regions that face the worst effects of climate-driven flooding, will be malaria and post-traumatic stress disorder, respectively. The economic impact of these illnesses and other flood-related health issues will top $1.6 trillion. 

The report found that floods, which pose the highest risk of climate-related mortality, will kill an estimated 8.5 million additional people globally by mid-century because of climate change. Droughts linked to extreme heat, the second-highest driver of climate mortality, will lead to more than 3 million extra deaths. The report estimates that 500 million additional people could be exposed to vector-borne diseases such as malaria, dengue fever, and Zika virus by 2050, many of them in regions that don’t typically have to contend with those illnesses today, such as Europe and the United States. The authors made these projections using a middle-of-the-road climate scenario, in which governments continue to make slow, halting progress toward achieving international climate goals. If fossil fuel use continues unabated or ramps up further through 2050, the health consequences of climate change will be much more severe, and millions more people will die. 

Daniel R. Brooks, a professor of evolutionary biology at the University of Toronto and author of a book on climate change and emerging diseases, told Grist that it’s encouraging that business-oriented institutions like the World Economic Forum are beginning to tally the direct and longer-term health effects of climate change. But he noted that more work needs to be done to capture the full scope of the climate change-related public health burden. “These staggering numbers are actually conservative,” said Brooks, who was not involved in the research. 

Large epidemiological blind spots cover much of Africa, southeast Asia, and other parts of the world that have historically lacked the resources to collect and publish health and climate data. That means that studies that use existing data to make their projections, as this report did, necessarily miss a big part of the picture. “It is imperative to recognize that the true toll of storms may be underestimated because of the lack of comprehensive data capturing indirect effects,” the report acknowledged in a section dedicated to the health effects of tropical storms. “This is particularly true for low-income and other vulnerable populations.” 

Developed countries are already armed with much of the information and many of the tools required to avert the mass casualties the report projects. The authors outlined a multi-pronged approach these countries can take. The first step is obvious and essential: Reduce greenhouse gas emissions as quickly as possible. Every tenth of a degree of warming dodged corresponds to hundreds of thousands of lives saved around the world. “The holy grail will lie in prevention,” said Rolf Fricker, a partner at Oliver Wyman and a coauthor of the report. “This is the most important thing.” 

Governments must also treat climate change like a public health crisis, and dedicate resources to establishing climate and health offices that will guide policy and divert resources to where they are needed. The United States is an example of a country that began such a process in 2021 by establishing an Office of Climate Change and Health Equity, which is waiting on congressional funding in order to begin the work of assessing and responding to the risks climate change poses to Americans’ health. The U.S. is something of an outlier in this respect. For example, Fricker, who lives in Germany, said his government hasn’t even begun to quantify the health risks of climate change, despite having to contend with expansive flooding issues and intensifying heatwaves in recent years. These climate impacts put hospitals, clinics, and other parts of Germany’s healthcare system at risk. 

In developing countries, where the resources to establish and fund such operations do not exist, wealthier governments, foundations, and private companies must step in to fill the void, Fricker said. The Bill and Melinda Gates Foundation has dedicated tens of millions of dollars to this effort, and other foundations are doing similar work, but the scale of investment needs to increase exponentially. A tiny fraction of the already limited international climate adaptation funding pledged to the Global South by wealthy nations is dedicated to health projects. More funding would allow at-risk countries to make their hospitals and clinics more resilient to climate change, stockpile medicines and vaccines that can protect people from the projected rise in vector-borne and diarrheal diseases, collect data on how climate change is affecting the public, and educate communities about the dangers at hand and ahead. 

Last week, Barbados, Fiji, Kenya, the United Kingdom, and a handful of other countries proposed a draft decision on climate change and health that calls on members of the United Nations to invest in some of the solutions proposed in the World Economic Forum report. The draft, which may be adopted in the spring at the 77th World Health Assembly — the decision-making body of the World Health Organization — suggests that nations carry out periodic climate and health assessments, conduct disease surveillance monitoring, and cooperate with other governments on the issue of climate change and human health. The draft, if adopted, would mark a historic and important step toward protecting people from the impacts predicted in the report. Brooks, the professor at the University of Toronto, is hopeful that 2024 will produce meaningful progress on the climate-health crisis. “Not only do we have a number of challenges that are being addressed individually by really smart people,” he said, “but all of those challenges connect with, and influence each other.”

This story was originally published by Grist with the headline Climate change will kill 14.5 million people globally by 2050 — but mostly not directly on Feb 1, 2024.

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A 16-month-old boy was playing in a splash pad at a country club in Little Rock, Arkansas, this summer when water containing a very rare and deadly brain-eating amoeba went up his nose. He died a few days later in the hospital. The toddler wasn’t the first person in the United States to contract the freshwater amoeba, Naegleria fowleri, this year. In February, a man in Florida died after rinsing his sinuses with unboiled water — the first Naegleria fowleri-linked death to occur in winter in the U.S. 

2023 was also an active year for Vibrio vulnificus, a type of flesh-eating bacteria. There were 11 deaths connected to the bacteria in Florida, three deaths in North Carolina, and another three deaths in New York and Connecticut. Then there was the first-ever locally transmitted case of mosquito-borne dengue fever in Southern California in October, followed by another case a couple of weeks later. 

Scientists have warned that climate change would alter the prevalence and spread of disease in the U.S., particularly those caused by pathogens that are sensitive to temperature. This year’s spate of rare illnesses may have come as a surprise to the uninitiated, but researchers who have been following the way climate change influences disease say 2023 represents the continuation of a trend they expect will become more pronounced over time: The geographic distribution of pathogens and the timing of their emergence are undergoing a shift. 

“These are broadly the patterns that we would expect,” said Rachel Baker, assistant professor of epidemiology, environment, and society at Brown University. “Things start moving northward, expand outside the tropics.” The number of outbreaks Americans see each year, said Colin Carlson, a global change biologist studying the relationship between global climate change, biodiversity loss, and emerging infectious diseases at Georgetown University, “is going to continue to increase.” 

That’s because climate change can have a profound effect on the factors that drive disease, such as temperature, extreme weather, and even human behavior. A 2021 study found water temperature was among the top environmental factors affecting the distribution and abundance of Naegleria fowleri, which thrives in water temperatures above 100 degrees Fahrenheit but can also survive frigid winters by forming cysts in lake or pond sediment. The amoeba infects people when it enters the nasal canal and, from there, the brain. “As surface water temperatures increase with climate change, it is likely that this amoeba will pose a greater threat to human health,” the study said. 

Vibrio bacteria, which has been called the “microbial barometer of climate change,” is affected in a similar way. The ocean has absorbed the vast majority of human-caused warming over the past century and a half, and sea surface temperatures, especially along the nation’s coasts, are beginning to rise precipitously as a result. Studies that have mapped Vibrio vulnificus growth show the bacteria stretching northward along the eastern coastline of the U.S. in lockstep with rising temperatures. Hotter summers also lead to more people seeking bodies of water to cool off in, which may influence the number of human exposures to the bacteria, a study said. People get infected by consuming contaminated shellfish or exposing an open wound — no matter how small — to Vibrio-contaminated water. 

Mosquitoes breed in warm, moist conditions and can spread diseases like dengue when they bite people. Studies show the species of mosquito that carries dengue, which is endemic in many parts of the Global South, is moving north into new territory as temperatures climb and flooding becomes more frequent and extreme. A study from 2019 warned that much of the southeastern U.S. is likely to become hospitable to dengue by 2050. 

Other warmth-loving pathogens and carriers of pathogens are on the move, too — some of them affecting thousands of people a year. Valley fever, a fungal disease that can progress into a disfiguring and deadly illness, is spreading through a West that is drier and hotter than it used to be. The lone star tick, an aggressive hunter that often leaves the humans it bites with a life-long allergy to red meat, is expanding northward as winter temperatures grow milder and longer breeding seasons allow for a larger and more distributed tick population. 

The effect that rising temperatures have on these diseases doesn’t necessarily signal that every death linked to a brain-eating amoeba or Vibrio that occurred this year wouldn’t have happened in the absence of climate change — rare pathogens were claiming lives long before anthropogenic warming began altering the planet’s dynamics. Future analyses may look at the outbreaks that took place in 2023 individually to determine whether rising temperatures or some other climate change-related factor played a role. What is clear is that climate change is creating more opportunities for rare infectious diseases to crop up. Daniel R. Brooks, a professor of evolutionary biology at the University of Toronto and author of a book on climate change and emerging diseases, calls this “pathogen pollution,” or “the accumulation of a lot of little emergences.” 

State and local health departments have few tools at their disposal for predicting anomalous disease outbreaks, and doctors often aren’t familiar with diseases that aren’t endemic to their region. But health institutions can take steps to limit the spread of rare climate-driven pathogens. Medical schools could incorporate climate-sensitive diseases into their curricula so their students know how to recognize these burgeoning threats no matter where in the U.S. they eventually land. A rapid test for Naegleria fowleri in water samples already exists and could be used by health departments to test pools and other summer-time hot spots for the amoeba. States could conduct real-time monitoring of beaches for Vibrio bacteria via satellite. Cities can monitor the larvae of the mosquito species that spreads dengue and other diseases and spray pesticides to reduce the numbers of adult mosquitoes. 

“If we were looking proactively for pathogens before they caused disease, we could better anticipate local outbreaks,” Brooks said. In other words, he said, we should be “finding them before they find us.”

This story was originally published by Grist with the headline The link between climate change and a spate of rare disease outbreaks in 2023 on Dec 22, 2023.

This post was originally published on Grist.