A years-long malaria control campaign in the Brazilian Amazon nearly eliminated the disease from a city — but then cases rebounded. Now, scientists think they've uncovered why.

The campaign took place in northern Brazil during the construction of the Belo Monte Dam in the Xingu River, one of the largest hydroelectric dams in the world. From 2013 to 2017, the initiative slashed annual malaria rates from more than 1,200 cases to fewer than 60. But the program ended, and within a few years, infections had rebounded to more than 700 cases a year. This time, they were concentrated in the rural communities surrounding the river in the city of Altamira.

In a study published Thursday (July 9) in the journal GeoHealth, scientists analyzed 15 years of malaria surveillance records alongside satellite images of forests around Altamira. Earlier studies have pointed to deforestation and dam construction as a driver of malaria because they can provide habitats for mosquito larvae, which inhabit the forest edge. In Altamira, large stretches of rainforest have been cleared for cattle ranching, logging and settlement along the Xingu River in the decades since the region was first opened up by road-building, leaving a patchwork of cleared land pressed up against the remaining forest.

However, the study found that the malaria resurgence wasn't simply a result of how much forest had been cut down. Instead, cases tracked most closely with the forest edge, the boundary where intact forest meets cleared or open land. There, mosquitoes get everything they need to thrive: shade from the tree line, sunlit pools of standing water for their larvae, and people living or working close by.

The findings highlight how the environment contributes to malaria risk, suggesting that maintaining surveillance in these high-risk landscapes could be just as important as driving cases down in the first place.

"What made Altamira compelling was that the timing gave us something rare, close to a natural experiment," study co-author Eloise Skinner, an epidemiologist and postdoctoral research fellow at the University of Queensland in Australia, told Live Science in an email. The results of that natural experiment could help Brazil in its efforts to eliminate malaria from the country in the next decade, she said.

A program tied to temporary funding

The researchers tracked malaria trends before, during and after the construction of the Belo Monte Dam. Before construction began, malaria was already a persistent problem in the region; Altamira city alone reported more than 1,200 cases a year.

As thousands of workers moved in, local health authorities and the dam's developers rolled out an intensive control program that involved spraying insecticides indoors, using mosquito nets, and deploying rapid diagnosis and treatment when cases did emerge. The goal was to head off outbreaks spread by Nyssorhynchus darlingi, the mosquito that carries the malaria-causing parasite in the Brazilian Amazon.

Mosquitoes pick up the parasite that causes malaria by feeding on the blood of infected people, and they can then spread that parasite to others they bite. Treating infected people quickly can help break that chain of transmission.

Cases plummeted despite the influx of workers, but once construction wrapped up and the program lost its funding, malaria came back.

To understand what drove the resurgence, the researchers combined three streams of data. Case records came from Brazil's national malaria surveillance system and covered 150 health centers in Altamira over 15 years. The team layered on temperature, forest cover and rainfall data, since both shape how favorable an area is for mosquito breeding and how efficiently the malaria parasite develops inside mosquitos. Plus, they added an estimate of travel time between each cluster of cases and the nearest town, as a proxy for how easily people and the diseases they carry might move around.

From the observations, the forest edge consistently emerged as the strongest predictor of increased malaria cases. For every 1% increase in the perimeter of the forest edge, malaria cases rose by roughly 0.7%; for every 1% increase in Altamira's population, who are located at the forest edge, cases rose by about 1.4%.

The rebound wasn't evenly distributed. Before the dam was built, most of Altamira's malaria cases came from clusters inside the city itself. Afterward, that pattern flipped: by 2020, the roughly 700 annual cases were concentrated almost entirely in remote, rural clusters near forest edges. Meanwhile, Altamira's urban center stayed comparatively protected, much as it had during construction.

"When the funded program wound down, malaria came back to the communities that are hardest for the health system to reach," Skinner said. "The city stayed protected, most likely because fast diagnosis and treatment are easier to deliver and keep going in a town."

That leaves the same communities exposed twice over, Skinner said. The places that are already the hardest to reach with health services also sit where the ecological risk is the highest.

But this pattern could point to solutions. The resurgence didn't scatter unpredictably. It came back to the same kind of place — rural communities at the forest edge — each time. That's the kind of risk that can be anticipated in the future.

Brazil aims to eliminate locally acquired malaria by 2035. Skinner said Altamira's near elimination of the disease, and its rebound within a few years of the control program ending, is a warning for that effort. When a community contains a strong environmental driver for malaria, like forest-edge ecosystems, stopping a control program short is sure to let the disease climb back.

"Because the resurgence wasn't diffuse, we can predict where malaria is likely to return first," Skinner said. "The message for a 2035 goal isn't only that elimination needs sustained investment. It is that where the environment drives risk, that risk is predictable, and planning for it from the start is what lets the money go where it matters most."

Scientists have invented a soft robotic heart that could give them a new way to study a mysterious condition that accounts for roughly half of all heart failure cases.

This form of heart failure, called heart failure with preserved ejection fraction (HFpEF), is a condition in which the heart pumps out a normal amount of blood but becomes too stiff to relax and refill properly between beats. Over 3 million Americans have the condition, but researchers still don't fully understand why it develops, making it difficult to design treatments that directly target the disease.

The new device, described June 1 in the journal Nature Communications, is the first soft robotic heart model that can actively adjust how it responds to changes in pressure. It tightens or relaxes its artificial muscles, enabling researchers to control how stiff the heart becomes. This allows it to better mimic a diseased human heart.

Current laboratory models of HFpEF have drawbacks. Traditional "mock circulation loops" use rigid pumps and tubing to recreate blood flow but don't physically resemble a beating heart. Lab animals capture more realistic biology but are expensive and don't perfectly mirror human disease, said study co-author Thanh Nho Do, a biomedical engineer and associate professor at the University of New South Wales in Australia.

"HFpEF has been notoriously difficult to study and treat," Nho Do told Live Science in an email.

Earlier versions of the robotic heart could realistically recreate cardiac movement, but they followed present commands that didn't adapt to changing conditions. The new system attempts to solve that limitation by allowing the artificial muscle fibers to "feel" the pressure created by the fluid they are pumping and dynamically contract or relax against it.

That feedback is critical for reproducing HFpEF, in which abnormal stiffness — rather than weakened pumping — lies at the core of the disease.

The researchers built a silicone replica of the left side of the human heart and wrapped it in artificial muscle fibers made from rubber tubes reinforced with spring coils. The model continuously senses the pressure generated by the fluid flowing through it and adjusts the force of its artificial muscles in response. By changing how much the muscles resist being stretched as the heart fills, researchers can dial in different levels of stiffness.

Instead of modeling a single snapshot of HFpEF, the researchers recreated several stages of the disease's progression. In early stages, patients' hearts start to show impaired relaxation between beats, while in more advanced forms, the heat is so stiff that it can't adequately fill with blood before the next contraction.

"If we can model its progression pathway, we might be able to use models like ours to develop medical devices that interrupt that trajectory, rather than just treating end-stage disease," Nho Do said.

Current treatment for HFpEF focuses largely on managing symptoms and associated conditions, such as high blood pressure, obesity and diabetes. In recent years, drugs known as SGLT2 inhibitors have been shown to reduce the risk of hospitalization in many patients by reducing excess fluid in the body. But there are still few therapies that directly target the stiffening of the heart muscle.

The researchers hope their new model might pave the way, but they emphasized that the work is an early proof of concept. Looking ahead, they hope to develop increasingly sophisticated robot heart models that can complement other data on HFpEF, including that from computer simulations, animal studies and clinical testing.

"We hope the biggest impact will be in understanding HFpEF mechanisms and improving the way we develop cardiovascular devices," Nho Do said.

Heart quiz: What do you know about the body's hardest-working muscle?

The fragile and battered remains of an infant who lived about 6,000 years in Mesopotamia may be the oldest documented case of child abuse from the Middle East and one of the oldest known cases of its kind in the world, a new study finds.

Researchers unearthed the infant's remains in Syria, but at the time the infant died, sometime between 4200 and 3900 B.C., it was buried in Tell Brak, one of the world's earliest cities. It's possible that the difficulties associated with early urbanization played a role in the child's abuse, the researchers noted.

The team determined that, based on the infant's tooth development, the child was 6 to 9 months old at death. An analysis of the remains, which were interred in a children's burial ground within a Late Copper Age workshop district, revealed that the infant had four fractured ribs near the breastbone. The right thigh bone had abnormal growth, while both sides of the skull bore active, porous lesions. These injuries point to the bones being subject to intense and repetitive external forces, and the nature of the lesions don't fit easily with an accidental fall, the researchers said.

"Ribs shouldn't break" in such a small child, study co-author Aleksandra Grzegorska, a bioarchaeologist at the University of Warsaw, told Live Science. Although rib fractures are relatively common in adults, they suggest child abuse in young infants, she said.

In the study, published May 21 in the International Journal of Osteoarchaeology, Grzegorska and her colleagues systematically ruled out other explanations for the injuries, including rickets, scurvy, birth trauma and violent coughing from illnesses such as tuberculosis. Vitamin deficiencies were unlikely, the researchers noted, given that ancient Mesopotamia had ample sunlight and fresh produce due to the fertile land between the two rivers. Birth-related fractures typically heal within weeks in infants, and bone density and growth measurements for the baby matched those of its peers from that time, indicating that the child didn't have an underlying skeletal condition.

To gauge how unusual the injuries were, the team compared the infant to other children excavated from the same burial area. None of the other youngsters with substantial rib preservation showed similar fractures, making the infant's injuries an outlier in the local population.

It appears that the infant likely experienced "caregiver-induced violence," Grzegorska said. This term is used because the evidence can't identify who caused the harm or confirm intent, Grzegorska said. "We don't want to point fingers at any specific individual," she said, noting that in many ancient cultures, multiple family members, not just parents, helped raise children.

Other clues that might shed light on the infant's injuries are missing from this case, she added. Unlike modern clinicians, bioarchaeologists can't interview a living patient or bystander, or examine soft tissue that might reveal more about the abuse. The partially healed state of the fractures suggest the infant survived for some time after the injuries were inflicted, Grzegorska found — an indication that the trauma was not immediately fatal.

Around the time the infant died, Tell Brak was transforming into a city, so the authors suggested that the stresses of early urbanization and possibly less support from extended kin could have contributed to the violence. Centuries after the infant died, upheavals related to city building appear to have led to mass deaths that were likely caused by violent conflict, Grzegorska noted.

Documented cases of child abuse remain exceptionally rare in the archaeological record, with only a handful previously identified in places such as Egypt, France and Lithuania.

The European Space Agency's (ESA) Euclid space telescope has spotted 31 previously unknown quasars dating to the universe's earliest chapter, including the two oldest ever found.

The discoveries, described July 6 in the journal Astronomy & Astrophysics, more than double the number of known quasars from that primordial era and could help astronomers unravel one of cosmology's biggest mysteries: how supermassive black holes grew so enormous so quickly after the Big Bang.

"It's a big step towards understanding these fascinating objects on a more fundamental level," Antonio La Marca, an ESA research fellow on the Euclid team, said in a statement.

Quasars are among the brightest objects in the universe. They form when gas and dust spiral into a galaxy's central supermassive black hole, heating up and releasing enormous amounts of energy that can outshine the galaxy itself. Each of the two most ancient quasars detected in the new study shone with the light of a trillion suns, according to the researchers.

Euclid spotted the quasars while surveying the distant universe. Twelve of them have redshifts of 7 or higher, meaning their light has traveled for more than 13 billion years and dates to the universe's first 770 million years. Two of the objects, with redshifts of 7.77 and 7.69, are the most ancient quasars ever identified, shining just 670 million years after the Big Bang, when the universe was only about 5% of its current age.

"These early quasars date back to the Universe's infancy," Daming Yang, an astronomer at Leiden University in the Netherlands and first author of the new study, said in the statement. "By finding and studying them, we can better understand how these enormous systems formed and grew so quickly — one of the greatest mysteries in astrophysics."

Finding quasars from the early universe has long been difficult because they are rare and incredibly distant. Until now, astronomers had identified only the brightest examples, making it difficult to understand the broader population during this early era. Euclid's wide-field survey is changing that by detecting fainter quasars across huge swaths of the sky.

The latest discoveries represent only a fraction of what the telescope is expected to find during its six-year mission, which will cover more than one-third of the total sky once complete. Mounted with a pair of instruments that see in visible and near-infrared light, Euclid is currently assembling the largest-ever 3D map of the universe. Scientists expect the survey to uncover hundreds of similarly ancient quasars, providing an unprecedented look at how the universe's earliest galaxies and supermassive black holes evolved.

Euclid has also taken some time to study the nearby universe, revealing more than 60 million individual stars packed into the Milky Way's center in a sparkling image released in late June.

Black hole quiz: How supermassive is your knowledge of the universe?

Deep in a limestone cave on Turkey's Mediterranean coast, archaeologists have uncovered evidence that Neanderthals and the modern humans who moved in later left behind surprisingly similar traces of their daily lives — evidence that they hunted the same animals, crafted the same stone tools and collected the same type of seashells.

The findings, published Monday (July 6) in the journal PNAS, feed into some of the biggest questions in human evolution: How similar were the cultures of Neanderthals and Homo sapiens, given that we're so closely related? And did we share information with one another?

A series of archaeological finds over the past few decades, including the new paper's finding that the two had similar cultural practices, suggests that Neanderthals and H. sapiens behaved far more similarly in the Middle East than once assumed.

The new evidence comes from Üçağızlı II Cave (pronounced Ooch-ah-UHZ'-luh), on a stretch of coastline just north of Syria that served as a prehistoric corridor between the Levant (an area of land east of the Mediterranean) and Eurasia. Although the team found only teeth and a partial jawbone within the cave, they were able to distinguish between the remains of Neanderthals and H. sapiens by analyzing the internal structure of the fossilized teeth. Meanwhile, they dated the sediment at the site using optically stimulated luminescence, a technique that reveals how long ago buried mineral grains last saw sunlight.

The team found that the Neanderthals had lived within the cave between approximately 77,000 and 59,000 years ago, while H. sapiens stayed there between about 59,000 and 47,000 years ago. Despite the different time periods, the layers from both of these periods show "substantially uniform hunting-gathering strategies and lithic technology," showing how similar the Neanderthals and H. sapiens were in their hunting-gathering strategies and stone-tool use, the team wrote in the study.

What's more, Neanderthals and H. sapiens got raw materials, such as flint, from the same local sources and hunted the same prey: wild goats (Capra aegagrus), fallow deer (Dama mesopotamica), roe deer (Capreolus capreolus) and wild boar (Sus scrofa). Layer after layer also turned up 29 shells of a small marine snail, Columbella rustica, carried into the cave not for food but seemingly as ornaments. Some were pierced as if meant to be strung, and one shell dating to the Neanderthal occupation showed signs of deliberate heating that altered its color.

"Our findings indicate a deep level of cultural interaction," study co-author Naoki Morimoto, paleoanthropologist at Kyoto University, said in a statement. "These two distinct but closely related human groups were not just adapting to the same environment: they were probably sharing symbolic preferences."

That pattern breaks from findings at Mandrin Cave in France, where Neanderthals and modern humans are thought to have alternated occupation in distinct pulses from about 56,800 and 41,500 years ago, but did not leave evidence of a continuous culture. Instead, it echoes evidence from Tinshemet Cave in Israel, where researchers recently reported similar signs of shared behavior between the two groups tens of thousands of years earlier, from about 130,000 to 80,000 years ago.

Üçağızlı II Cave in Turkey and Tinshemet Cave in Israel suggest that even though there was a "biological" turnover as the caves went from being occupied by Neanderthal groups to modern humans, there weren't major cultural turnovers, too.

"Rather, we hypothesize that the two human species that coexisted in the region were in contact and shared cultural aspects," the researchers wrote in the study.

"A fascinating region"

Sites like these are forcing a rethink of how these two types of human were culturally related to each other, April Nowell, a Paleolithic archaeologist at the University of Victoria in Canada who was not involved in the new study, told Live Science in an email. "By demonstrating cultural continuity and elevated levels of interaction, sites such as Tinshemet and Üçağızlı II are changing what we thought we knew about Neandertals, Homo sapiens and other contemporary Homo groups … a fascinating region just got even more so!" she said.

But that cultural continuity only heightens the mystery of how modern humans and Neanderthals interacted, with Neanderthals eventually going extinct around 40,000 years ago. Two types of human can't occupy the same ecological niche indefinitely, Nowell noted, and some research into Neanderthal cognition suggests Neanderthals were less-flexible thinkers than modern humans, with more limited capacity for language and less of the kind of self-awareness and creativity that may have given H. sapiens an edge. (However, there is pushback against the idea that Neanderthals weren't as cognitively complex as H. sapiens.)

If the archaeological record at sites like Üçağızlı II shows this much overlap in behavior, Nowell said, the real differences between the two may be ones the fossil record simply hasn't revealed yet.

The authors noted that many big questions remain, including when and where these shared cultural practices took place and whether these cultural similarities happened because modern humans mated with Neanderthals.

Ongoing and future excavations at sites like Üçağızlı II Cave may help to answer these questions and build a "more comprehensive picture of human evolution and cultural development during the Late Pleistocene," the team wrote in the study.

How much do you know about our closest relatives? Find out with our Neanderthal quiz!

Astronomers have spotted an ancient galaxy shining through the cosmic fog of the early universe, revealing a detailed view that was thought to be impossible.

Using NASA's Hubble Space Telescope, along with data from the James Webb Space Telescope (JWST) and the European Southern Observatory's Very Large Telescope (VLT), researchers detected "ionizing" ultraviolet photons — energetic light capable of stripping electrons from hydrogen atoms — coming from the galaxy, called MXDFz4.4. It's the earliest such detection on record, arriving only around 250 million years after the end of a major cosmic transition called the Epoch of Reionization, the researchers explained in a study published June 23 in The Astrophysical Journal.

For hundreds of millions of years after the Big Bang, the space between galaxies was filled with a fog of neutral hydrogen gas that blocked this kind of light. Over time, radiation from the first stars and galaxies ionized that gas, clearing the fog and letting light travel freely across the universe — a process astronomers are still working to fully understand.

"This was thought to be impossible," Ilias Goovaerts, a postdoctoral fellow at the Space Telescope Science Institute (STScI) in Baltimore and first author of the new study, said to Live Science. "What’s really special about this galaxy is that it’s getting through so much of the intergalactic medium [the ionized plasma between galaxies]. It’s the furthest away so it has the most intergalactic medium to get through."

What makes MXDFz4.4 unusual is its combination of size and star-formation rate. The galaxy is roughly 100 times smaller by area than the Milky Way, yet it forms stars around 10 times faster, packing a large number of massive young stars into a compact space. According to Goovaerts, that crowding effect helps the galaxy punch clear channels through its surrounding gas, letting ionizing light escape both the galaxy and, eventually, the murky space between galaxies. The team estimates that somewhere between half and all of the galaxy's ionizing light is escaping.

The discovery, made in October, came about somewhat by chance. While preparing an unrelated funding proposal just days before a major deadline, Goovaerts examined an existing, deep Hubble image to check whether anyone had looked for this kind of signal there before. Within a couple of hours, he had a promising signal. "It was very, very quick from us having the idea to me going, okay, there’s something here and this is exciting," Goovaerts said. "We were excited from day one, but then it took months for it to mature and to extract all the properties about the galaxy."

The finding relied on an unusually rich set of observations: an extremely deep Hubble image taken from 40 hours of observations; JWST imaging across many wavelengths, used to characterize the galaxy's stars and star-formation history; and one of the deepest spectra ever taken of a single patch of sky, gathered over roughly six days of observing time with the VLT's Multi-Unit Spectroscopic Explorer instrument. That spectrum confirmed the galaxy's distance through its Lyman-alpha emission line — which serves as a "hydrogen fingerprint," or a glow given off by excited hydrogen gas, that astronomers can use to measure cosmic distance and time.

No other galaxy from this early period had previously shown detectable ionizing light, making MXDFz4.4 one of a kind so far, study co-author Marc Rafelski, deputy mission head for the Hubble Space Telescope at STScI, noted in the statement. .

Researchers say bursts of vigorous star formation like the one seen in MXDFz4.4 may have played an important role in clearing the early universe's hydrogen fog and that more galaxies like it are likely still waiting to be found.

James Webb Space Telescope quiz: How well do you know the world's most powerful telescope?

Two lumps of potato discovered in a roughly 500-year-old Inca storage room in Peru are a rare find: freeze-dried potatoes predating the Spanish invasion, a new study finds.

These freeze-dried potatoes, known as chuño, were once a backbone of the Inca Empire's food supply and a product so fragile that they almost never turn up at archaeological sites.

The new discovery, made along Peru's arid south coast, is only the second time chuño has been recovered from an Inca site, researchers reported in the new study. It is concrete evidence that the empire directed one of its most important food sources hundreds of miles from the Andes, down to the Pacific Ocean.

Chuño is made by repeatedly exposing potatoes to nighttime frost and daytime sun until nearly all their moisture has evaporated, leaving a lightweight, long-lasting vegetable that can be stored for decades. This technique works only at high elevations where hard frost occurs regularly, so chuño had to be produced in the mountains and then transported using llama caravans, often hundreds of kilometers, to feed people living elsewhere in the empire.

The Inca used the same drying method to preserve meat, producing a product called "charki" — the source of the English word "jerky," study principal investigator Lidio Valdez, an adjunct professor in the Department of Anthropology and Archaeology at the University of Calgary, told Live Science in an email.

In the new study, published May 1 in the Journal of Field Archaeology, Valdez and study co-author Katrina Bettcher, an independent archaeologist, reported that the chuño was found alongside an Inca pottery fragment and a broken spindle whorl, a tool used to spin fibers, such as raw wool, into yarn or thread.

The discovery happened during the 2024 field season at Tambo Viejo, an Inca provincial center in the Acarí Valley, where an archaeological team had worked for several years. Inside a small storage room, the team uncovered a clay pot sunk into the dirt floor, its top half long gone. As researchers scooped soil out of the broken pot, they reached its bottom.

"Almost at the base of the vessel, the two samples of freeze-dried potatoes were found," Valdez said. "They showed me without knowing what they were, and right away I said: chuño!"

Potatoes are roughly 80% water, and they typically rot within a week at lower, warmer elevations — making them a poor food choice for long-distance storage. Valdez said freeze-drying was likely discovered long before the Inca rose to power in the 15th century, perhaps when potatoes that were accidentally exposed to frost at a high elevation became dried out and people realized the result was still edible.

Because chuño can be made only above roughly 11,800 feet (3,600 meters), the samples at Tambo Viejo must have traveled down from the highlands, most likely via a llama caravan along the Inca road network, Valdez said.

"Chuño being a light product probably also made its transportation easier," he added.

The two freeze-dried potatoes survived thanks to the Acarí Valley's extremely dry conditions, which help preserve organic remains that would otherwise decay — the same conditions that have previously yielded naturally mummified guinea pigs (Cavia porcellus) in Valdez’s previous work at the site.

Beyond its archaeological importance, the ancient preservation method has lessons for today. "We still have so much to learn from the people of the past," Valdez said. "Food security is a main concern, even in our times; yet we waste food, perhaps more than at any time in human history."

Relatively few Inca sites along Peru's coast have been systematically excavated, and Valdez expects more evidence of chuño — and the long supply lines that carried it — to surface as archaeologists keep digging.

Do you know where pumpkins and blueberries come from? Find out with our fruits and vegetables quiz!