A blood test could determine whether a feverish baby has a bacterial or viral infection in 15 to 20 minutes. This would help doctors gauge whether the infection is serious or may pass without treatment, which could prevent unnecessary use of antibiotics.

When babies are brought into hospital with fever, they 鈥渁re considered high-risk until proven otherwise鈥�, says at the Giannina Gaslini Institute in Genoa, Italy.

A fever can be the result of several things, including infection by viruses or bacteria. These different types of pathogens require different medications. Furthermore, most common viruses are fairly benign, while bacterial infections are generally more dangerous, says Bellini.

Existing tests to gauge infection type take at least a few hours, so babies with fever are often given antibiotics against bacteria as a precautionary measure. But only about 15 per cent of them actually have a serious bacterial infection, says Bellini. This unnecessary use of antibiotics helps drive the spread of bacterial resistance.

To develop a test that determines infection type, Bellini and his colleagues followed 85 babies, all younger than 90 days old, who were brought into emergency rooms with fever after previously having no serious health concerns. The team took blood samples and tested for two proteins: CD64 and CD169.

Previous studies have shown that these proteins become more common in certain blood cells when the body responds to infections. CD64 is made at higher levels in response to bacteria and is found on the surface of white blood cells called neutrophils. and appears on the outer membranes of monocytes, another type of white blood cell.

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By in neutrophils and monocytes, the test correctly identified all 15 cases of bacterial infection, 44 incidences of viral infection and 26 cases of no infection. Bellini presented the results at the in Paris, France.

The results came through in 15 to 20 minutes in a lab, says Bellini, who is trying to develop a version that can be used as quickly in hospitals.

This builds on several years of research to develop a CD64/CD169 test. at Beckman Coulter Life Sciences in Marseille, France, has spent much of the past decade working on it. In 2021, his team found that among adults in an emergency room.

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Other groups have since , found ways to more , and demonstrated that . Performing the test on babies in a hospital setting is a significant advance, says Malergue. It was crucial to investigate the test in this age group because their immune systems are still developing, which meant 鈥渟ome people had doubts about the capacity of these [CD64 and CD169] markers to arise鈥�, he says.

Malergue says one of his collaborators used the test in Martinique during an outbreak of dengue fever, which is caused by a virus and is usually mild. The collaborator found that some people actually had a bacterial infection called leptospirosis, which is life-threatening without antibiotics.

Bellini now hopes to assess the test in a trial of 300 to 500 infants at multiple hospitals. Meanwhile, Malergue and his colleagues have developed that can quickly analyse finger-prick blood samples to determine whether an infection is viral or bacterial, which is approved for research use.

A group of enigmatic ancient humans called the Denisovans thrived in what is now south-west China for more than 100,000 years. They lived in a conifer forest and hunted large animals like deer.

It is the first evidence of Denisovans in this region, and one of the only known sites with artefacts that can tell us about how they lived. For the first time, 鈥渨e can know their technology and know their subsistence strategy鈥�, says , an archaeologist at the Institute of Tibetan Plateau Research in Beijing.

The new site is only the third Denisovan locale 鈥渨here we have everything鈥�, says at the University of Toronto in Canada, who wasn鈥檛 involved in the study. 鈥淲e have human remains, we have lithics [stone artefacts], we have fauna, we have the environmental context.鈥� The other two sites are Denisova cave in Siberia and Baishiya Karst cave on the Tibetan plateau.

The Denisovans were hominins that lived in East Asia within the past few hundred thousand years. They were first identified 16 years ago from DNA preserved in a finger bone in Denisova cave. A smattering of other Denisovan remains have since been found elsewhere in East Asia, including Harbin in northern China.

However, for聽almost all of these remains, it is impossible to study their archaeological context 鈥� particularly in the case of聽. Because of this, we have little information about the tools and other artefacts they made.

The new finds come from Bianfu cave in Yunnan province. The area has been heavily quarried, destroying much of the cave, including the entrance, but in 2019 local workers spotted animal fossils and alerted the authorities. This led Li and his colleagues to conduct a rescue excavation that summer.

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They dug three trenches to a depth of 6.6 metres, revealing 18 layers of sediment 鈥� of which 10 contained artefacts made by hominins. One of these layers yielded four intact hominin teeth.

The excavation also unearthed over 64,000 fragments of bone. To find out whether any belonged to hominins, a team led by at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing first went through them by hand. The researchers identified 22 potential hominin remains, which they subjected to molecular analysis. Three proved to be from hominins: two fragments of skull and a piece of radius (an arm bone).

They tried extracting DNA from the three bones, but to no avail. Fu says the warm climate in the region and the age of the fossils were 鈥渦nsuitable for DNA preservation鈥�. However, the team did manage to obtain proteins from the three bones and two of the teeth. All five held protein variants that are unique to Denisovans, and none had any protein variants specific to H. sapiens or Neanderthals. Fu and her colleagues therefore determined that all the remains came from Denisovans.

The bones and teeth appear to be different ages, so Li鈥檚 team concluded that they come from at least four individuals. The two studied teeth had telltale protein variants showing they belonged to males.

The researchers dated the bones themselves and the surrounding sediments using multiple methods. They determined that the bones are between 134,000 and 167,000 years old. However, the artefacts cover a longer time frame: 70,000 to 190,000 years ago.

鈥淲e think this is one hominin species who occupied the site for a long time,鈥� says Li. The excavators found a total of 1366 stone artefacts. These included 135 flakes and the cores from which they had been removed, along with simple tools such as scrapers and choppers. In general, the artefacts were relatively simple, compared with those made by Neanderthals living elsewhere in Eurasia at the same time.

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However, the Denisovans also seem to have been successful hunters. The team found 1654 identifiable animal bones, including large numbers of deer and bovids (hoofed animals that include cows and gazelles), plus rhinoceroses, hyenas and bamboo rats. Many of the bones had telltale marks suggesting they had been butchered by hominins; few showed any sign of being gnawed by non-human animals. Deer and bovids were the main prey, and the bones suggest the Denisovans generally hunted animals in prime condition.

Li says the Denisovans clearly had a 鈥渧ery skilful hunting strategy鈥� to be able to bring down such prey. He argues they probably relied less on stone tools than other hominin groups, explaining why the stone artefacts they found were relatively crude. The team discovered seven bone tools, and Li suspects the Denisovans used these a lot. They may also have used tools made of wood or bamboo, which have since decayed.

This may reflect the comfortable environment in which these Denisovans lived. 鈥淚t鈥檚 a different ecosystem from where we had them previously,鈥� says Viola. Pollen evidence suggests the area was a mix of conifer forest and steppe, with a temperate climate and rich wildlife.

Denisovans elsewhere, such as those in Siberia or on the Tibetan plateau, faced greater environmental challenges like cold and low oxygen. They may well have developed different technologies and strategies to cope, says Li. Such places may have been at the limits of their range, while locations like Bianfu cave were in their heartland.