Posted by: maboulette | March 18, 2020

Long-Dormant Bacteria and Viruses Are Reviving as Earth’s Climate Warms

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All throughout history, human beings have lived side-by-side with viruses and bacteria.  From the bubonic plague to smallpox, humans have learned to resist them and in response they have developed new ways of infecting us.

NATURAL STALEMATE

When antibiotics were developed 100 years ago with the discovery of penicillin, what did bacteria do – they evolved to be resistant to many of the evolving antibiotics.  This battle is almost endless – because we spend a lot of time with pathogens and we sometimes develop a kind of natural stalemate.  But, think about this, what would happen if we were suddenly exposed to deadly viruses and bacteria that have been missing for thousands of years, or those we have never met before?

CLIMATE CHANGE

With climate change we are about to find out.  The warming of the climate is melting permafrost soils that have been frozen for thousands of years and as this soil melt, they are releasing ancient viruses and bacteria that have been dormant – and now spring back to life.  In August 2016, in a remote part of the Siberian tundra known as the Yamal Peninsula in the Arctic Circle, a 12-year-old boy died and as many as 20 were hospitalized after being infected with anthrax.

THEORY OF WHAT HAPPENED

How did this happen?  The theory is that over 75 years ago, a reindeer infected with anthrax died and its carcass was frozen and trapped under a layer of frozen soil, – permafrost.  And that is where it stayed until a heatwave during the summer of 2016, when the permafrost thawed.  This exposed the body of the dead reindeer and released infectious anthrax into nearby water and soil and then directly into the food supply. Over 2000 reindeer feeding nearby became infected, which then led to small number of human cases.  And the fear is that this will not be an isolated case.

CONTINUES TO WARM

As the world continues to warm, more permafrost will melt.  Under normal circumstances, superficial permafrost layers are about 50 cm or 1.5 feet melt every summer.  But now with global warming there is gradually older layers of permafrost being exposed.  Frozen permafrost soil is the perfect place for bacteria and viruses to stay alive for very long time periods, perhaps as long as a million years. That means melting ice could potentially open a Pandora’s box of diseases.

ARCTIC CIRCLE

The temperature of the Arctic Circle is quickly rising, almost 3 times faster than in the rest of the world.  As the ice and permafrost melt, other infectious agents may be released.  Evolutionary biologist Jean-Michel Claverie has said,

“Permafrost is a very good preserver of microbe and viruses, because it is cold, there is no oxygen and it is dark.  Pathogenic viruses that can infect humans or animals might be preserved in old permafrost layers, including some that have caused global epidemics in the past.”

EARLY 20th CENTURY

In the early parts of the 20th Century alone, over a million reindeer died from anthrax.  It is not easy to dig deep graves, so most of these bodies are buried close to the surface, scattered among 7000 burial grounds in northern Russia.  But the big fear is what else can be lurking beneath this frozen soil.

BURIED FOR CENTURIES

Animals and people have been buried in the permafrost for centuries, so it is entirely conceivable that other infectious agents could be released.  For example, scientists have discovered fragments of RNA from the 1918 Spanish flu virus in corpses buried in mass graves in Alaska’s tundra.  Bubonic plague and smallpox are also very likely to be buried in Siberia.

STUDY IN 2011

In a study in 2011, Boris Revich and Marina Poolnaya wrote:

“As a consequence of permafrost melting, the vectors of deadly infections of the 18th and 19th centuries may come back, especially near the cemeteries where victims of these infections were buried”.

REVIVED BACTERIA

NASA scientists have successfully revived bacteria that has been encased in a frozen pond in Alaska for 32,000 years.  The microbes, called Carnobacterium pleistocenium, had been frozen since the Pleistocene period, when woolly mammoths still roamed the earth.  Once the ice melted, they began swimming around, seemingly unaffected.  Once they were revived, the viruses quickly became infectious.

MILLIONS OF YEARS OLD

Two years later, scientists managed to revive an 8-million-year old bacterium that had been lying dormant in ice, beneath the surface of a glacier in the Beacon and Mullins valleys of Antarctica.  In that same study, bacteria were also revived from ice that was over 100,000 years old.

STILL ALIVE IN ICE

More and more of these studies are finding bacteria and viruses long believed to be eradicated are still alive as this ice and frozen permafrost melt.  But it gets worse!

MEXICAN MINE

In February 2017, NASA scientists announced that they had found 10 to 50,000 year-old microbes inside crystals in a Mexican mine.  The bacteria found somehow become resistant to 18 different types of antibiotics.  The bacteria were located in the Cave of the Crystals, part of a mine in Nacica in northern Mexico.  This cave contains many milky-white crystals of the mineral selenite, which formed over hundreds of thousands of years.  The bacteria were trapped inside small, fluid pockets of the crystals, but once they were removed, they revived and started to multiply.  The microbes are genetically unique and may well be a new species, but these researchers have yet to publish their work.

CAVE IN NEW MEXICO

Even older bacteria have been found in Lechuguilla Cave in New Mexico, 1000 ft underground.  These microbes have not seen the surface for over 4 million years. The cave never sees sunlight and it is so isolated that it takes about 10,000 years for water from the surface to reach this cave.  And antibiotic resistance has been around for millions or even billions of years.  These bacteria have somehow become resistant to 18 types of antibiotics, including drugs considered to be a “last resort” for fighting infections.  In a study published in December 2016, researchers found that the bacteria, known as Paenibacillus sp. LC231, was resistant to 70% of antibiotics and was able to totally inactivate many of them.

RESISTANCE TO ANTIBIOTICS

All the bacteria have remained completely isolated in the cave for 4 million years, they have not come into contact with people or the antibiotic drugs used to treat human infections.  That means its antibiotic resistance must have arisen in some other way.  Scientists involved believe that the bacteria, which does not harm humans, is one of the many that have naturally evolved resistance to antibiotics.  This suggests that antibiotic resistance has been around for millions or even billions of years.

HOW DOES THIS HAPPEN

The reason for this is that many types of fungi, and even other bacteria, naturally produce antibiotics to gain a competitive advantage over other microbes.  This is how Fleming first discovered penicillin: bacteria in a petri dish died after one became contaminated with an antibiotic-excreting mold.

2011 STUDY

In fact, with the ancient hidden bacteria, natural antibiotic resistance is possibly so prevalent that many of the bacteria emerging from melting permafrost may already have it.  In line with that, in a 2011 study scientists extracted DNA from bacteria found in 30,000-year-old permafrost in the Beringian region between Russia and Canada.  They found genes encoding resistance to beta-lactam, tetracycline and glycopeptide antibiotics.

How much should we be concerned about all this?

 


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