Climate change could bring new epidemic

COVID-19 |

The virus, which had been sleeping for a long time, has revived. The deadly and ugly reappearance of smallpox The dengue or zika “season” in Europe.

These may be the story lines of disaster films, but they are also serious and increasingly plausible scenarios of epidemics released by global warming, scientists say.

COVID-19’s pandemic, which swept the earth and claimed more than 760,000 lives so far, almost certainly originated from wild bats, and the constant invasion of humanity into the ever-decreasing planet’s wild space. Emphasize the danger.

However, the expanding ecological footprint of our species can also cause epidemics in other ways.

Climate change-already causing havoc with 1 degree Celsius warming-infectious diseases by expanding the footprints of mosquitoes carrying malaria and dengue or thawing prehistoric pathogens from Siberian permafrost Is emerging as a driver for.

“Ignorance is our enemy”

Birgitta Evengard, a researcher in clinical microbiology at the University of Umea in Sweden, said: “When I am the darkest, we see a truly terrifying future for Homo sapiens, because we are animals.

“Our greatest enemy is our own ignorance,” she added. “Nature is full of microorganisms.”

Think about permafrost, a climate-changing time bomb spread over Russia, Canada, and Alaska that contains three times as much carbon released since industrialization began.

According to the UN Climate Science Panel, the IPCC, even though humans could reduce global warming to less than 2 degrees, the permafrost area, the fundamental goal of the 2015 Paris Agreement, would be 4 by 2100. It is reduced by a factor of 1.

And there are hidden treasures of permafrost.

“Microorganisms can survive in the frozen space for long periods of time,” said Vladimir Romanovsky, geophysics professor at the University of Alaska Fairbanks.

Revival of anthrax?

He explained that as thaw on the ground, once frozen soil particles, organic matter, and microbes that had been locked for thousands of years, were carried to the surface by a stream of water.

“That is how thawing can spread these microbes into the modern environment.

There are already examples of frozen bugs.

“If you put the seeds in the soil and freeze them for thousands of years, nothing happens,” said Jean-Michel Crabley, emeritus professor of genomics at the University of Ex-Marseille in France.

“But when you warm the earth, the seeds can germinate,” he added. “This is similar to what happens with a virus.”

Claverie’s lab has been able to revive the Siberian virus at least 30,000 years ago.

These revived worms only attack the amoeba, but tens of thousands of years ago, there were certainly other worms that furthered the food chain.

“The Neanderthals, mammoths, and Woolly rhinos all fell ill and many died,” said Clavery. “Some of the viruses that caused their disease are probably still in the soil.”

The number of bacteria and viruses lurking in permafrost is immeasurable, but a more important question is how dangerous they are.

And here the scientists disagree.

“Anthrax shows that bacteria have been resting in permafrost for hundreds of years and can revive,” Evengard said.

In 2016, a Siberian child died of a disease that disappeared from the area at least 75 years ago.

Pathogens 2 million years ago

The case is allegedly due to the thawing of long buried carcasses, but some experts argue that the animal in question may be in shallow soil and may have been thawed regularly.

Other pathogens-smallpox or influenza strains that killed tens of millions of people in 1917 and 1918-may also exist in the Arctic.

But they are “probably inactivated,” Romanovsky concluded in a study published earlier this year.

However, in the case of Crabberry, the return of smallpox, which was officially declared eradicated 50 years ago, cannot be ruled out. Victims of the disease in the 18th and 19th centuries were “buried in a Siberian cemetery and completely protected by the cold,” he said.

In the rare event of a local epidemic, vaccines are available.

The real danger he added is that unknown pathogens that have not been exposed to sunlight for over two million years are in deeper geological formations that may be exposed by global warming.

It’s okay if no hosts are infected by the bug, but climate change also intervenes here indirectly.

“With the industrial exploitation of the Arctic, there are all the risk factors. Pathogens and the people who carry them,” Claverry said.

While the revival of ancient bacteria and viruses remains speculative, climate change has already fueled the spread of malaria, dengue, chikungunya, and deer, diseases that kill some 500,000 people each year.

“Mosquitoes that move the range north can now overwinter in some temperate regions,” said Jeanne Faire, deputy group leader in biosecurity and public health at Los Alamos National Laboratory in New Mexico.

“They also have a longer breeding period.”

“Climate change aperitif”

Native to Southeast Asia, the Tiger Mosquito, which carries the Dengue and Chikungunya fever, arrived in southern Europe during the first decade of this century, and has since moved northward to Paris and elsewhere.

Meanwhile, another dengue vector mosquito, Aedes aegypti, has also appeared in Europe. The European Centers for Disease Control and Prevention (ECDC) registered 40 cases of community-acquired dengue fever between 2010 and 2019, which may be due to either species.

“If a virus-infected A. aegypti is established, rising average temperatures can cause seasonal transmission of dengue fever in Southern Europe,” said the Centers for Disease Control and Prevention in Europe.

For malaria-a disease for which there are effective treatments that once struck southern Europe and the southern United States-the risk of exposure depends primarily on socioeconomic conditions.

If climate change continues unabated, more than 5 billion people could live in malaria-affected areas by 2050, according to a study cited by the IPCC. , That number could drop to less than 2 billion.

“Recent experience in Southern Europe shows how rapidly the disease can recur if health services deteriorate,” the IPCC said in 2013, implying a case relapse in Greece in 2008. It was

In Africa, 228 million malaria cases occurred in 2018, accounting for 94% of the world total. Vectors of this disease are moving to new areas, especially in the high plains of Ethiopia and Kenya.

At the moment, the signs of an infectious tropical disease are “worried about the spread of the vector, not necessarily an infection,” says Cyril Kaminard, an epidemiologist working on climate change at the Institute of Infectious Diseases and International Health at the University of Liverpool. Stated.

“But so far, I’ve only tasted climate-changing aperitifs,” he added.