AFP UK

As the Delta variant continues its global surge, experts are questioning whether the long-held goal of achieving herd immunity from Covid-19 through vaccination is still viable.

Herd immunity is achieved when a certain threshold of the global population has either been inoculated against a pathogen or has recovered from infection.

But whether or not it is achievable with Covid-19, with the regular emergence of more infectious strains, is up for debate.

“If the question is ‘will vaccination alone allow us to dampen and control the pandemic?’ the answer is: no,” epidemiologist Mircea Sofonea told AFP.

He said herd immunity hinged on two basic factors.

“That’s the intrinsic infectiousness of the virus and the efficacy of vaccines to protect against infection. And at the moment, that efficacy isn’t there.”

Delta has shown to be roughly 60 percent more transmissible than the Alpha variant of the SARS-CoV-2 virus, and up to twice as infectious as the original strain that emerged in late 2019. 

The more effective the virus becomes at infecting people, the higher the herd immunity threshold becomes.

“Theoretically, it’s a very simple calculation to make,” said epidemiologist Antoine Flahault. 

For the original virus, which had a reproduction rate between zero and three — meaning each infected person infects up to three others — herd immunity could have been achieved with around 66 percent of people immunised, Flahault told AFP.

“But if the reproduction rate is eight, as with Delta, that puts us closer to 90 percent,” he said.

Were vaccines 100 percent effective at stopping Delta infections, that 90 percent could conceivably be possible. Unfortunately, they aren’t. 

– Waning immunity? –

According to data published this week by US authorities, the efficacy of the Pfizer and Moderna mRNA vaccines at preventing infection has fallen from 91 percent to 66 percent since Delta became the dominant variant.

And studies have shown that the vaccine efficacy against infection with Delta falls over time — one of the reasons why several countries are now readying for an autumn third shot, or “booster”, vaccination campaign.

With all this taken into account, absent other health measures such as mask-wearing or social distancing, Sofonea said it would take more than 100 percent of people to be vaccinated in order to guarantee transmissions end — an obvious impossibility. 

“The Delta variant will still infect people who have been vaccinated and that does mean that anyone who’s still unvaccinated, at some point, will meet the virus,” Andrew Pollard, director of Britain’s Oxford Vaccine Group, told lawmakers this month.

– ‘Mythical’ –

But even if, as Pollard termed it, the “mythical” aim of herd immunity is no longer in play, experts stressed that getting vaccinated remained paramount.

As with vaccines against other, now-endemic diseases such as measles and influenza, the Covid vaccines offer excellent protection against severe illness.

“What scientists are recommending is to get the maximum number of people protected” through vaccination, said Flahault. 

Eventually, of course, all pandemics end. 

Sofonea said it would still be possible that Covid would become another endemic disease over time, “just not with vaccines alone”.

He envisioned a near future where “masks and social distancing continue in certain regions” in order to limit transmission and, ultimately, severe illness.

“During the AIDS pandemic, when scientists said we needed to wear condoms, lots of people said: ‘OK, we’ll do it for a while’,” said Flahault.

“And in the end they kept on using them. It could well be that we will continue using masks in enclosed spaces and on transport for quite some time.”

A new approach using existing medicines to prevent malaria has been shown to reduce severe cases of the parasitic disease among infants by more than 70 percent in sub-Saharan Africa, according to a study.

The “dramatic” results, published in the New England Journal of Medicine on Wednesday, came from combining booster shots of an antimalarial vaccine ahead of the rainy season together with preventative drugs.

Malaria kills more than 400,000 people a year, the vast majority under the age of five.

The paper’s senior author Brian Greenwood of the London School of Hygiene and Tropical Medicine told AFP that members of the team were in touch with the World Health Organization about updating its recommendations.

The RTS,S vaccine, made by British pharmaceutical company GSK, was developed more than 20 years ago but by itself is not highly effective, said Greenwood.

Prior research has shown the vaccine’s protection wanes over time and it offers around 30 percent efficacy over a period of three to four years.

Since malaria is highly seasonal in the Sahel and sub-Sahel region, the team wanted to test whether giving boosters before each year’s rainy season, when mosquito populations peak, would improve outcomes.

The trial followed around 6,000 children aged five to 17 months from Burkina Faso and Mali over the course of three years.

The children were split into three groups: those who received only the anti-malarial drugs sulfadoxine–pyrimethamine and amodiaquine; those who received only the RTS,S vaccine; and those who received a combination.

The combination was the most effective intervention, reducing malaria cases by 63 percent, hospitalizations by 71 percent, and deaths by 73 percent compared to the drugs alone.

“That was pretty dramatic,” said Greenwood — stressing that these numbers are on top of the impact of the already effective drugs, not compared to no medicine, which would have been unethical to test.

He estimated that the combination of the booster vaccine doses and antimalarial drugs reduced hospitalizations and deaths by 90 percent compared to no intervention.

Children initially receive three doses of the vaccine to prime their systems, then a booster every year. It is based on a particle that trains the immune system against the Plasmodium falciparum parasite.

The anti-malarial drugs are given for three days a month every four months.

Greenwood said the study showed the value of developing plans in accordance with local epidemiological conditions — in this case administering vaccines ahead of peak season, instead of during times when there was no transmission and their impact would fade.

“Like a lot of these things it’s sort of common sense but nobody has actually put this into practice, to see whether it actually would work,” he said.

“Hopefully this may get implemented in several countries and save lots of people’s lives.”

Up to 95 percent of Earth’s ocean surface will have changed by the end of the century unless humanity reins in its carbon emissions, according to research published Thursday. 

Ocean surface climates, defined by surface water temperature, acidity and the concentration of the mineral aragonite — which many marine animals use to form bones and shell — support the vast majority of sea life. 

The world’s seas have absorbed around a third of all carbon pollution produced since the Industrial Revolution.

But with atmospheric CO2 levels increasing at a rate unprecedented in at least three million years, there are fears that ocean surface climates may become less hospitable to the species it hosts. 

US-based researchers wanted to see what effect carbon pollution has already had on ocean surface since the mid-18th century. They also projected the impact of emissions through to 2100.

To do so, they modelled global ocean climates across three time periods: the early 19th century (1795-1834); the late 20th century (1965-2004); and the late 21st century (2065-2014). 

They then ran the models through two emissions scenarios. The first — known as RCP4.5 — envisions a peak in greenhouse gas emissions by 2050 followed by a slow decrease across the rest of the century.

The second scenario — RCP8.5 — is a “business as usual” approach, where emissions continue to rise throughout the next 80 years.

Writing in the journal Nature Scientific Reports, the researchers found that under the RCP4.5 scenario, 36 percent of the ocean surface conditions present throughout the 20th century are likely to disappear by 2100.

Under the high emissions scenario, that figure rises to 95 percent. 

The team also found that while ocean surface climates showed little sign of change during the 20th century, by 2100, up to 82 percent of ocean surface may experience climates not seen in recent history.

These include seas that are hotter, more acidic and that contain fewer minerals vital for sea life to grow.

Lead study author Katie Lotterhos, from Northeastern University’s Marine Science Center, said the ocean’s changing composition due to carbon pollution would likely impact all surface species.

“Species that are narrowly adapted to a climate that is disappearing will have to adapt to different conditions,” she told AFP.

“A climate in which the temperature and chemistry of the water is common today will be rare or absent in the future.”

– Diminishing options –

While surface species have so far been able to move around in order to avoid anomalously warm or acidic areas of ocean, Thursday’s study suggests that in the future their options may be limited due to near-uniform warming and acidification.

“Already, many marine species have shifted their ranges in response to warmer waters,” said Lotterhos. 

“The communities of species that are found in one area will continue to shift and change rapidly over the coming decades.”

She said that governments needed to monitor future shifting habits in marine surface species. 

But, ultimately, the world’s oceans need the emissions driving their heating and acidification to cease.

“Without (emissions) mitigation, novel and disappearing climates in the sea surface will be widespread around the globe by 2100,” said Lotterhos.

A village in the Austrian Alps known for its family-friendly ski resort has been forced to adapt to waning snow due to climate change, turning to a new downhill sport — mountain biking.

Bikers as young as three ride over landscaped jumps and curved forest trails, breathing new life into Sankt Corona am Wechsel, around an hour’s drive from Vienna, and offering a model for other struggling resorts.

“We used to be a 100 percent winter destination. Now, we have to think about climate change, and summers are booming,” said Karl Morgenbesser, who runs the adventure park in Sankt Corona.

As the coronavirus pandemic increases enthusiasm for outdoor activities, many Austrians hope mountain biking and other summer sports can make up for winter losses in the Alpine nation, where skiing accounts for around three percent of the GDP. 

Nearly a month of snow cover has been lost in the Alps at low and medium altitude in half a century, according to a March study published in The Cryosphere scientific journal.

And a recent report by the UN’s Intergovernmental Panel on Climate Change (IPCC) found that in the Alps the snow cover will decrease in areas below 1,500 metres (5,000 feet) throughout the 21st century.

– Lift pulls bikers up –

Situated at an altitude of nearly 900 metres, Sankt Corona dismantled its winter infrastructure in 2014 after years of losses as annual visitor numbers fell to 25,000 from 70,000 some 20 years earlier.

A rollercoaster-like summer toboggan and climbing space soon opened, but the 400-resident village’s fortunes truly turned when it devised a network of mountain-biking trails.

While most mountain biking destinations boast steep slopes, Sankt Corona’s undulating trails suit professionals as well as children relying on training wheels, and now draw about 130,000 visitors per season.

“We really like to come here as a family,” said 33-year-old Lisa Goeschl, who used to ski in Sankt Corona as a child and whose husband is an avid mountain biker.

“I think summer is a bigger hit with people (than winter) because there are so many activities on offer.”

This June, a new T-bar lift — which pulls bikers up the slope — opened, as a shuttle bus service taking riders to the top could no longer keep up with demand.

“I wanted the T-bar lift to be as simple as possible,” Simon Hanl, a local mountain biker who conceived the system to pull up the bikers, told AFP.

– ‘Inspirational’ –

Former snowboard instructor Morgenbesser hosts delegations from some of the world’s biggest ski resorts, curious to see how the tiny, low-lying village has adapted so well to a possibly snowless future. 

“It’s extremely inspirational,” said Marlene Krug, in charge of bike development in Saalbach, Austria, which frequently hosts mountain biking world cup races, and has now modelled part of its kids’ area after Sankt Corona’s.

Ski resorts first reacted to the lack of snow by investing to make it artificially. 

But temperatures have become so warm that resorts across the Alps will have to look into other options, says Robert Steiger, a University of Innsbruck expert on the impacts of climate change on tourism.  

“Diversifying into summer is necessary for all of them, and mountain biking is definitely something everyone’s interested in,” Steiger says.

Streetlights — particularly those that use white light-emitting diodes (LEDs) — not only disrupt insect behavior but are also a culprit behind their declining numbers, a new study carried out in southern England showed Wednesday.

Artificial lights at night had been identified as a possible factor behind falling insect populations around the world, but the topic had been under-researched.

To address the question, scientists compared 26 roadside sites consisting of either hedgerows or grass verges that were lit by streetlights, against an equal number of nearly identical sites that were unlit.

They also examined a site with one unlit and two lit sections, all of which were similar in their vegetation.

The team chose moth caterpillars as a proxy for nocturnal insects more broadly, because they remain within a few meters of where they hatched during the larval stage of their lives, before they acquire the ability to fly.

The team either struck the hedges with sticks so that the caterpillars fell out, or swept the grass with nets to pick them up.

The results were eye-opening, with a 47 percent reduction in insect population at the hedgerow sites and 37 percent reduction at the roadside grassy areas.

“We were really quite taken aback by just how stark it was,” lead author Douglas Boyes, of the UK Centre for Ecology and Hydrology, told AFP, adding the team had expected a more modest decline of around 10 percent.

“We consider it most likely that it’s due to females, mums, not laying eggs in these areas,” he said. 

The lighting also disturbed their feeding behavior: when the team weighed the caterpillars, they found that those in the lighted areas were heavier.

Boyes said the team interpreted that as the caterpillars not knowing how to respond to the unfamiliar situation that runs counter to the conditions they evolved in over millions of years, and feeding more as a result to rush through their development.

The team found that the disruption was most pronounced in areas lit by LED lights as opposed to high-pressure sodium (HPS) lamps or older low-pressure sodium (LPS) lamps, both of which produce a yellow-orange glow that is less like sunlight.

LED lamps have grown more popular in recent years because of their superior energy efficiency.

The paper acknowledged the effect of street lighting is localized and a “minor contributor” to declining insect numbers, with other important factors including urbanization and destruction of their habitats, intensive agriculture, pollution and climate change.

But even localized reductions can have cascading consequences for the wider ecosystem, resulting in less food for the birds and bats that prey upon insects.

Moreover, “there are really quite accessible solutions,” said Boyes — like applying filters to change the lamps’ color, or adding shields so that the light shines only on the road, not insect habitats.

Five tonnes of fish and crustaceans have washed ashore over the past 10 days at Spain’s Mar Menor, once a lagoon paradise that is slowly dying from agricultural pollution. 

The sparkling saltwaters have spat out millions of dead or dying sea creatures on to sandy beaches which have long drawn tourists to the southeast.

Images of dying fish forcing their heads above the surface, gasping for oxygen alongside baskets piled high with countless dead creatures have traumatised the Murcia region, raising urgent questions about the Mar Menor’s future.

On Monday, regional officials said they had removed 4.5-5.0 tonnes of remains but huge numbers of sea creatures are still dying. 

“The worst-ever wildlife death toll in the Mar Menor is not yet over,” the World Wildlife Fund (WWF) tweeted on Wednesday.

“It’s a terrible situation,” said Pedro Garcia, director of regional conservation organisation ANSE, who feared the death toll could be twice that given by the authorities. 

Beneath the calm of one of Europe’s largest saltwater lagoons — 135 square kilometres (52 square miles) separated from the Mediterranean by a 22-kilometre sandbar — a toxic storm has been brewing as a result of years of nutrient pollution from intensive agriculture.

“I haven’t been able to swim here for three years with this horrible stench,” a woman on the beach told Spain’s RTVE public television. 

– Turning a blind eye? –

Experts say the fish suffocated due to a lack of oxygen caused by hundreds of tonnes of nitrates from fertilisers leaking into the waters.

For years, runoff water loaded with nitrates has entered the lagoon causing a vast bloom of algae which, as it dies and decomposes, decreases oxygen levels in the depths.

Known as eutrophication, the phenomenon is an environmental hazard that causes aquatic ecosystems to collapse due to a lack of oxygen.

Visiting the lagoon on Wednesday, Environment Minister Teresa Ribera accused the regional government of turning a blind eye to farming irregularities in the Campo de Cartagena, a vast area of intensive agriculture that has grown tenfold over the past 40 years.

“There is no room for complacency,” she told reporters, indicating that 8,000 hectares of land lacked “adequate irrigation rights” and were “illegally extracting water or using a quantity far above their allocation”. 

But agricultural groups feel they are being unjustly targeted. 

“They are attacking a sector that scrupulously complies with all (environmental) legislation,” Vicente Carrion, regional head of the COAG farmers’ association, told AFP. 

– ‘Very damaged landscape’ – 

However, for Murcia’s association of biologists, there is absolutely no doubt that the nitrate-loaded runoff water “explains the ongoing eutrophication crisis which has caused such high animal mortality, the terrible stench and the cloudiness of the lagoon,” it said in a statement. 

It is the second such episode in less than two years although this has been the worst by far with the last incident in October 2019 causing the deaths of around three tonnes of marine life. 

ANSE’s Gracia says that although the nitrate runoff is the main issue, it is not the only problem.

The crisis is exacerbated by “the excessive number of marinas, destruction of the coastline by urban development and by the large quantity of mining sediment” entering the water.

“It’s a very damaged landscape,” he said. 

The mid-August heatwave also did not help Mar Menor’s sealife. 

According to Spain’s Institute of Oceanography, eutrophication “reduces its capacity to resist disruptions like those caused by the thermal stress of a heatwave”.

In the fictional links he drew between immortal vampires and bats, Dracula creator Bram Stoker may have had one thing right. 

“Maybe it’s all in the blood,” says Emma Teeling, a geneticist studying the exceptional longevity of bats in the hope of discovering benefits for humans.

The University College Dublin researcher works with the charity Bretagne Vivante to study bats living in rural churches and schools in Brittany, western France.  

“We’re taking a little bit of blood, but rather than us being the vampires to the bats we’re making them give us their secrets,” she says.

Those secrets are tantalising. 

Bats not only live longer than other animals of their size, they also stay healthy longer and can harbour pathogens like Ebola or coronaviruses without getting sick. 

Teeling, who outlined her research to AFP in an interview reproduced here in edited form, focuses on long-lived Greater Mouse-eared bats.

The aim is to discover the key to longer, healthier lives for people.   

“I firmly believe it lies in studying bats,” she says.

– What’s so special about bats? –

Typically in nature there is a pattern — nearly a law — that small things live very fast and die young as a consequence of a really fast metabolism. 

Bats are unique, they are some of the smallest of all mammals, yet they can live for an extraordinarily long time. They seem to have evolved mechanisms to slow down the ageing process.

It’s not eternal youth — everything dies and ageing has to catch up with you, but the rate of ageing is much slower in bats, their health span is much longer.

Think of a centenarian who is really healthy until the last few weeks of their life. That’s what we want and it’s what the bats have.

– How do you extract their secret? –

Nobody knew what was happening to bats as they age.

The only way you age a bat is to look at the bones in their fingers, if the joints are not yet fused, that bat is still a baby, once they’re fused it is an adult. 

But since 2010 Bretagne Vivante has put a little microchip like you would a dog or a cat, it’s called a pit tag, under the skin of these bats when they are babies. 

Every year we come back to these roosts where the females give birth and we catch the entire colony, we take a little bit of wing, a little bit of blood, and we go back to my lab in Ireland and we look at what has changed as they age, tracking a few biomarkers of ageing. 

– What are you looking for? –

We look at these things called telomeres: on the end of every one of your chromosomes in your cells you have these protective caps — like the bumper on a car — and every time your cells replicate, it gets shorter and shorter. 

They get really short, the cell should self-destruct but sometimes it stays around and becomes old, potentially driving the ageing process.

But in the longest-lived bats like Greater Mouse-eared bats, the telomeres do not shorten with age. They can protect their DNA. 

We sequenced genes from young, middle-aged and older bats and what we found was extraordinary — they increase their ability to repair their DNA with age and repair the damage that living causes. Ours decreases.

As we age, we get arthritis, we suffer from inflammation, the bats don’t seem to do this and the question is how?

So we found that they repair damage to their DNA and they are also able to modulate their immune response, keeping it balanced between antiviral and anti-inflammatory responses. 

When you look at Covid-19 for example, what kills somebody is this over-excited immune response. In Dublin, we did an experiment looking at antiviral and anti-inflammatory cytokines and found that if a human with a bat’s immune profile was hospitalised they wouldn’t end up on a ventilator. If it is the other way around, so more like a mouse, they end up on a ventilator.

We share the same genes as bats, with slight tweaks and modifications. Imagine if we find the little controlling gene that regulates these effects, we could then make a drug to mimic it in humans. 

– How long will it take? –

I would have said 10 years, but look how fast everything is going now. 

People are really interested in looking at bats to find answers, there’s been a huge speed up.

We sequenced the genome, that was the first step, then we have this field data and we’re working with labs all around the world who are developing the cellular tools required.

We have to keep going and believe it’s possible.

It could be a scene from a bad horror movie: Torchlights slice through the darkness inside a church in western France as the building echoes with the shrieks of hundreds of bats.

But these creatures of the night are scaring no one. 

They are having their annual check-up, as scientists try to unravel the secrets of an animal whose fiendish reputation has eclipsed its many gifts to the world.

Dozens of Greater Mouse-eared bats are passed from hand to hand — gloved to avoid a bite — by volunteers and scientists in Saint Martin’s church at Noyal-Muzillac, in Brittany.  

Each bat is painstakingly examined, its sex, height and weight noted, its blood taken, teeth checked for wear, translucent wings stretched out and inspected. 

A male pup, born just a few weeks ago in the church rafters, is hanging upside down by its claws in a tube placed on a weighing scale: 19.7 grams (0.7 ounces).

Once the physical assessment is finished, the latest addition to the colony is implanted with a tag, no bigger than a grain of rice.  

“They put a little microchip like you would a dog or a cat, it’s called a pit tag, under the skin on these bats when they are babies and they release them,” said Emma Teeling, head of zoology at University College Dublin. 

This is a ritual that has been repeated every year for a decade by the organisation Bretagne Vivante, which captures and checks the entire colony to help understand and safeguard this protected dark-furred species. 

Why lavish so much attention on such a maligned creature? 

Because they are one of the world’s most endangered animals — threatened by habitat loss and by human persecution.

  

– Seeds and super powers –

Long demonised as fanged monsters or vectors of disease, the pandemic has done little to improve bats’ image, after the World Health Organization said the coronavirus likely originated in the animals. 

Rodrigo Medellin, who co-leads the International Union for Conservation of Nature (IUCN) Bat Group, said he has never worked harder to defend them. 

But the only mammal capable of flight has a lot more to offer than viruses and vampire legends. 

If you have ever sipped coffee, eaten a taco or worn a cotton t-shirt, you can thank bats, Medellin told AFP. 

Fruit-eating species help disperse seeds from tree to tree, while some bats are indispensable pollinators.

Some species can swallow half their weight in insects each night, according to Bat Conservation International.

“They are the best natural pesticide,” said Medellin, of Mexico’s Universidad Nacional Autonoma, adding that even tequila can be traced to millions of years of bat pollination of the agave plant. 

“The benefits we receive from them are so huge and so different that they touch every day of our life,” said Medellin. 

But it is not just what bats do that makes them special. 

They also have an array of innate talents that fascinate scientists.  

Engineers are inspired by their natural sonar, enabling them to fly low and find their way thanks to echolocation. 

And yes, they can harbour viruses like coronaviruses or Ebola. But why do they not fall ill? 

Bats also seem to have evolved a way to slow down the ageing process, said Teeling, whose lab in Ireland is exploring how these creatures stay healthy almost until the end of their lives.

Little animals typically “live fast, die young”, she said, explaining that a reduced body size often means a fast metabolism: the lifespan of a mouse is often measured in months, while a bowhead whale can live for over a century.  

“In nature, when you look at the body size of something, you can predict how long they are going to live for,” she said. 

Not bats.

The Greater Mouse-eared Bats that Teeling and her colleagues study do not exceed eight centimetres (just over three inches), but they can live up to 10, or even 20 years. 

In 2005, researchers in Siberia captured a Brandt’s bat that had been tagged 41 years earlier, estimating it had lived nearly 10 times longer than expected for its size.

– ‘Ecological traps’ – 

From the tiny two-gram “bumblebee bat”, to the giant Philippine flying fox with its 1.5-metre (five-foot) wingspan, bats make up a fifth of all terrestrial mammals. 

But some 40 percent of the 1,321 species assessed on the IUCN’s Red List are now classified as endangered. 

“We are losing species all over the world,” said Julie Marmet, chiropterologist (bat expert) at the National Museum of Natural History in France. 

Bats have been “resilient” for 50 million years, she told AFP, but today’s changes are “far too fast for species to adapt”. 

Human actions are to blame, as with the biodiversity crisis gripping the entire planet — which will come under the spotlight at the IUCN congress in early September. 

Deforestation and habitat loss is the primary driver. 

Many species live in trees and the 40 percent that live in caves depend largely on forests for foraging, said Winifred Frick, chief scientist at Bat Conservation International. 

Climate change is also increasingly taking its toll. 

Flying foxes in Australia have been devastated by heatwaves, while in the United States thousands of Mexican free-tailed bats have been killed by hypothermia. 

Lured by milder winters into abandoning their habitual migration south, many of these little bats have taken to staying in their roosts under bridges in Texas during the cooler months. 

These bridges over waterways look like “restaurants” for bats, said Frick, but it also represents an “ecological trap”. 

During the last winter, there was a particularly cold snap in Texas.  

“Thousands and thousands of bats died during that big freeze,” she said.  

– Hunted and harassed –

Modern human infrastructure has become a perilous obstacle course.

Already victims of collisions with cars, they must now avoid wind turbines — studies suggest half a million are killed every year in the US either by the blades or the deadly effects of the forceful air movement.  

Even the automatic motion sensors that illuminate the stairways of apartment blocks can turn a short stopover for migrating pipistrelles into a waking nightmare. 

Normally these matchbox-sized bats only fly at night, said Andrzej Kepel, of the Polish association Salamandra.

But when they try to continue with their migration after a couple of days in these stairways, they trigger the sensor and the lights turn on.    

“So they land,” said Kepel. Again and again they try to leave and every time the lights flick on, stopping them. 

Their cries can attract others. 

“After several days, there are hundreds of bats in the staircase and people are panicking,” he said. Bats can end up starving to death.

Inside caves, they are still not safe. 

Whether it is tourists shining torches or the incursions of those collecting bat guano to use as fertilizer, the slightest disturbance can be devastating. 

Especially since most bat species only have one baby per year, unusually for such a small mammal, said Marmet.  

So “if there is a problem in a colony, it’s over.”

Hunted for meat or sport by people in Southeast Asia and Africa, they also fall prey to other animals. 

In Jamaica, for example, cats have staked out the cave of a colony of critically endangered bats.  

“We’ve documented within an hour cats taking about 20 bats, ripping their wings off and snacking on them,” said Frick.

– Vampires to Vatican – 

So who is frightening who? 

Bats have not always had a bad reputation.  

In Mayan culture they played a major role in the forming of the universe. 

But in the Western world they have been unwittingly typecast as mascots of Halloween and horror films.

While just three types of bats in South America are (animal) blood-drinking “vampires”, when Bram Stoker wrote “Dracula” in the 19th century it tarnished the reputation of the whole family.  

“That is the moment bats began to be accused of being envoys of the devil, being evil, and filthy, and bringing diseases,” said Medellin.

Batman was helpless to redress the balance. 

Even Pope Francis last year likened people in a state of sin to being “like ‘human bats’ who can move about only at night”. 

But many of those who spend time with bats end up loving them. 

“They are cute! We get attached to them,” says Corentin Le Floch, of Bretagne Vivante. 

In the church of Noyal-Muzillac, it’s snack time and a Greater Mouse-eared bat is nibbling on a wriggling mealworm. 

He gets a quick caress of his little pointy ears and then: freedom.

Thousands of indigenous protesters marched through Brazil’s capital Wednesday, dancing to the beat of pounding drums, as the Supreme Court prepared to take up a case that could eliminate reservations on their ancestral lands.

In what organizers said was the country’s biggest indigenous protest ever, an estimated 6,000 demonstrators marched to the seat of power in Brasilia, filling the ultra-modern square bordered by the Supreme Court, Congress and the presidency with traditional costumes and chants.

The protest aimed to pressure the high court as it began a session where it will consider a case that could remove protected status for some native lands, opening them to agribusiness and mining.

The protesters, who hail from more than 170 ethnic groups, were also fighting what they call systematic persecution under far-right President Jair Bolsonaro.

“The Supreme Court needs to listen to the concerns of indigenous peoples and protect our constitutional rights,” said Jatota Wajapi, 32, of the Wajapi people in the northern state of Amapa.

“The president wants to do away with our rights,” he told AFP.

The protest was peaceful, with organizers urging demonstrators to avoid confrontations with police.

A similar protest in June erupted into clashes, with three indigenous demonstrators injured and three police wounded by arrows.

The court case revolves around the Brazilian constitution’s protection of indigenous lands.

The agribusiness lobby argues those protections should only apply to lands whose inhabitants were present in 1988, when the constitution was adopted.

Indigenous rights activists argue the constitution mentions no such time limit, and that native inhabitants have often been forced from their ancestral lands.

Indigenous protesters have been camped out near the high court since Sunday, and plan to remain for a week — though it is unclear how long the ruling will take.

The court adjourned Wednesday without getting to the case, the second on its docket.

– ‘Brutally expelled’ –

The case involves a reservation in the southern state of Santa Catarina but will set legal precedent for similar cases across Brazil, experts say.

The plaintiffs are the Xokleng, Guarani and Kaingang peoples of the Ibirama-Laklano indigenous reservation, part of which lost protected status when a lower court ruled the groups were not living on the land in question in 1988.

They say that is because Brazil’s military dictatorship (1964-1985) forcibly removed them.

“During the dictatorship, the state sold our land to farmers. The reason we weren’t there (in 1988) is because they expelled us and forced us onto a tiny corner,” Ana Patte, a 29-year-old Xokleng activist, told AFP.

“Everyone knows how brutal the process of colonization was in Brazil… They killed us as if we were insects they had to clean up so they could plant crops.”

– Legal onslaught –

The implications of the case are far-reaching.

Experts say it will set legal precedent for dozens — potentially hundreds — of similar cases, at a time when a powerful, Bolsonaro-backed agribusiness lobby has been aggressively moving to rewrite the rules on protected lands in Brazil.

The case echoes legislation before Congress that would enshrine the 1988 “time-frame argument” in law.

The bill is one of several that indigenous activists and environmentalists say Bolsonaro and his allies are trying to use to further the advance of agriculture and industry into Brazil’s rapidly disappearing forests.

Environmentalists say protecting indigenous reservations is one of the best ways to stop the destruction of the Amazon, a critical resource in the race to curb climate change.

Bolsonaro warned Tuesday that “chaos” would ensue if the court did not rule in favor of the 1988 cutoff.

“There’s land that’s productive today that could stop being productive… It would be chaos for Brazil and a great loss for the world,” he said.

Bolsonaro has vowed in the past that “not one centimeter” of new indigenous reservations will be created in Brazil.

A team of archeologists examining the remains of victims from the eruption of Mount Vesuvius in 79 AD have discovered coastal people of the time ate far more fish than modern Italians, with men getting more of the high-status food than women.

The researchers, led by a team at the University of York, analyzed amino acids — the building blocks of proteins — in 17 adult skeletons excavated from the city of Herculaneum, a popular seaside resort that remained buried under volcanic ash until the 18th century.

By studying the ratio of carbon and nitrogen isotopes of the amino acids and applying a statistical model, they were able to differentiate between food groups with a new level of precision, the team wrote in the journal Science Advances on Wednesday.

Lead author and PhD student Silvia Soncin told AFP that Herculaneum provided an “extraordinary population” to study historic diets because the natural disaster gives archeologists a snapshot in time.

“Cemeteries are usually used over a certain period, we’re talking about hundreds of years, and the food sources may have changed because of changing climate or different trade routes,” she said.

Though Herculaneum and nearby Pompeii were destroyed by the volcano, most inhabitants managed to escape in time, senior author Oliver Craig, a professor of bioarcheology told AFP.

The 11 men and six women studied by the team were picked at random from 340 people who died on the beach and from nine adjacent fornici — stone chambers for boats — where they had sought shelter from the pyroclastic flow.

“We found a surprisingly high amount of marine contribution to the diet of these people, particularly compared to the modern Mediterranean population,” said Soncin, with the ancient dwellers eating about three times the amount of seafood compared to their counterparts today.

Herculaneum’s sewers were filled with fish bones, prior research has shown. Typical species would have included porgies, tuna and shellfish.

– Gender gap –

They also discovered a significant sex gap within the group, with males on average getting 50 percent more of their protein from seafood compared to females.

Men also got slightly more protein from cereals compared with their female contemporaries, while women obtained more of their proteins from animal products and locally grown fruits and vegetables.

The team put forward several possible reasons: men may have been more involved in fishing than women, but the historical record also shows that certain fish such as tuna were considered high-status food in Roman society, with men having more access.

Another aspect is that, although Herculaneum was known as a resort for the elite, it was also home to many slaves and freedmen, said Craig. 

Male slaves had a higher chance of emancipation than women and were generally freed at an earlier age, giving them more access to coveted foods.

“Now we’ve got a way and approach for actually quantifying diet in the past, so what we want to do is apply this more widely through time and space,” said Craig.

He hopes to next examine how quickly diets shifted when prehistoric humans moved from hunter-gathering activities to agricultural societies.