I have written several articles on the coronavirus and on masks and healthcare issues. A series of links have been provided at the bottom of this article for your convenience. This article will, however address a different aspect of the virus or on healthcare issues in general.
I came across an posting in history.com, entitled “Pandemics That Changed History.” The article was so well done, that I can’t improve on it, so I have included it in its entirety below. I have done so, because I feel that the more information people have access to the better. I want to show that we have survived many pandemics throughout our history, and we will survive this one. As long as we don’t give up and remain strong, we will overcome this pandemic. At least we know how to fight it. Our ancestors were not as lucky.
In the realm of infectious diseases, a pandemic is the worst case scenario. When an epidemic spreads beyond a country’s borders, that’s when the disease officially becomes a pandemic.
Communicable diseases existed during humankind’s hunter-gatherer days, but the shift to agrarian life 10,000 years ago created communities that made epidemics more possible. Malaria, tuberculosis, leprosy, influenza, smallpox and others first appeared during this period.
The more civilized humans became, building cities and forging trade routes to connect with other cities, and waging wars with them, the more likely pandemics became. See a timeline below of pandemics that, in ravaging human populations, changed history.
430 B.C.: Athens
The earliest recorded pandemic happened during the Peloponnesian War. After the disease passed through Libya, Ethiopia and Egypt, it crossed the Athenian walls as the Spartans laid siege. As much as two-thirds of the population died.
The symptoms included fever, thirst, bloody throat and tongue, red skin and lesions. The disease, suspected to have been typhoid fever, weakened the Athenians significantly and was a significant factor in their defeat by the Spartans.
165 A.D.: Antonine Plague
The Antonine plague was possibly an early appearance of smallpox that began with the Huns. The Huns then infected the Germans, who passed it to the Romans and then returning troops spread it throughout the Roman empire. Symptoms included fever, sore throat, diarrhea and, if the patient lived long enough, pus-filled sores. This plague continued until about 180 A.D., claiming Emperor Marcus Aurelius as one of its victims.
250 A.D.: Cyprian Plague
Named after the first known victim, the Christian bishop of Carthage, the Cyprian plague entailed diarrhea, vomiting, throat ulcers, fever and gangrenous hands and feet.
City dwellers fled to the country to escape infection but instead spread the disease further. Possibly starting in Ethiopia, it passed through Northern Africa, into Rome, then onto Egypt and northward.
There were recurring outbreaks over the next three centuries. In 444 A.D., it hit Britain and obstructed defense efforts against the Picts and the Scots, causing the British to seek help from the Saxons, who would soon control the island.
541 A.D.: Justinian Plague
The plague changed the course of the empire, squelching Emperor Justinian’s plans to bring the Roman Empire back together and causing massive economic struggle. It is also credited with creating an apocalyptic atmosphere that spurred the rapid spread of Christianity.
Recurrences over the next two centuries eventually killed about 50 million people, 26 percent of the world population. It is believed to be the first significant appearance of the bubonic plague, which features enlarged lymphatic gland and is carried by rats and spread by fleas.
11th Century: Leprosy
Though it had been around for ages, leprosy grew into a pandemic in Europe in the Middle Ages, resulting in the building of numerous leprosy-focused hospitals to accommodate the vast number of victims.
A slow-developing bacterial disease that causes sores and deformities, leprosy was believed to be a punishment from God that ran in families. This belief led to moral judgments and ostracization of victims. Now known as Hansen’s disease, it still afflicts tens of thousands of people a year and can be fatal if not treated with antibiotics.
1350: The Black Death
Responsible for the death of one-third of the world population, this second large outbreak of the bubonic plague possibly started in Asia and moved west in caravans. Entering through Sicily in 1347 A.D. when plague sufferers arrived in the port of Messina, it spread throughout Europe rapidly. Dead bodies became so prevalent that many remained rotting on the ground and created a constant stench in cities.
England and France were so incapacitated by the plague that the countries called a truce to their war. The British feudal system collapsed when the plague changed economic circumstances and demographics. Ravaging populations in Greenland, Vikings lost the strength to wage battle against native populations, and their exploration of North America halted.
1492: The Columbian Exchange
Following the arrival of the Spanish in the Caribbean, diseases such as smallpox, measles and bubonic plague were passed along to the native populations by the Europeans. With no previous exposure, these diseases devastated indigenous people, with as many as 90 percent dying throughout the north and south continents.
Upon arrival on the island of Hispaniola, Christopher Columbus encountered the Taino people, population 60,000. By 1548, the population stood at less than 500. This scenario repeated itself throughout the Americas.
In 1520, the Aztec Empire was destroyed by a smallpox infection. The disease killed many of its victims and incapacitated others. It weakened the population so they were unable to resist Spanish colonizers and left farmers unable to produce needed crops.
Research in 2019 even concluded that the deaths of some 56 million Native Americans in the 16th and 17th centuries, largely through disease, may have altered Earth’s climate as vegetation growth on previously tilled land drew more CO2 from the atmosphere and caused a cooling event.
1665: The Great Plague of London
In another devastating appearance, the bubonic plague led to the deaths of 20 percent of London’s population. As human death tolls mounted and mass graves appeared, hundreds of thousands of cats and dogs were slaughtered as the possible cause and the disease spread through ports along the Thames. The worst of the outbreak tapered off in the fall of 1666, around the same time as another destructive event—the Great Fire of London.
1817: First Cholera Pandemic
The first of seven cholera pandemics over the next 150 years, this wave of the small intestine infection originated in Russia, where one million people died. Spreading through feces-infected water and food, the bacterium was passed along to British soldiers who brought it to India where millions more died. The reach of the British Empire and its navy spread cholera to Spain, Africa, Indonesia, China, Japan, Italy, Germany and America, where it killed 150,000 people. A vaccine was created in 1885, but pandemics continued.
1855: The Third Plague Pandemic
Starting in China and moving to India and Hong Kong, the bubonic plague claimed 15 million victims. Initially spread by fleas during a mining boom in Yunnan, the plague is considered a factor in the Parthay rebellion and the Taiping rebellion. India faced the most substantial casualties, and the epidemic was used as an excuse for repressive policies that sparked some revolt against the British. The pandemic was considered active until 1960 when cases dropped below a couple hundred.
1875: Fiji Measles Pandemic
After Fiji ceded to the British Empire, a royal party visited Australia as a gift from Queen Victoria. Arriving during a measles outbreak, the royal party brought the disease back to their island, and it was spread further by the tribal heads and police who met with them upon their return.
Spreading quickly, the island was littered with corpses that were scavenged by wild animals, and entire villages died and were burned down, sometimes with the sick trapped inside the fires. One-third of Fiji’s population, a total of 40,000 people, died.
1889: Russian Flu
The first significant flu pandemic started in Siberia and Kazakhstan, traveled to Moscow, and made its way into Finland and then Poland, where it moved into the rest of Europe. By the following year, it had crossed the ocean into North America and Africa. By the end of 1890, 360,000 had died.
1918: Spanish Flu
The avian-borne flu that resulted in 50 million deaths worldwide, the 1918 flu was first observed in Europe, the United States and parts of Asia before swiftly spreading around the world. At the time, there were no effective drugs or vaccines to treat this killer flu strain. Wire service reports of a flu outbreak in Madrid in the spring of 1918 led to the pandemic being called the “Spanish flu.”
By October, hundreds of thousands of Americans died and body storage scarcity hit crisis level. But the flu threat disappeared in the summer of 1919 when most of the infected had either developed immunities or died.
1957: Asian flu
Starting in Hong Kong and spreading throughout China and then into the United States, the Asian flu became widespread in England where, over six months, 14,000 people died. A second wave followed in early 1958, causing an estimated total of about 1.1 million deaths globally, with 116,000 deaths in the United States alone. A vaccine was developed, effectively containing the pandemic.
First identified in 1981, AIDS destroys a person’s immune system, resulting in eventual death by diseases that the body would usually fight off. Those infected by the HIV virus encounter fever, headache, and enlarged lymph nodes upon infection. When symptoms subside, carriers become highly infectious through blood and genital fluid, and the disease destroys t-cells.
AIDS was first observed in American gay communities but is believed to have developed from a chimpanzee virus from West Africa in the 1920s. The disease, which spreads through certain body fluids, moved to Haiti in the 1960s, and then New York and San Francisco in the 1970s.
Treatments have been developed to slow the progress of the disease, but 35 million people worldwide have died of AIDS since its discovery, and a cure is yet to be found.
First identified in 2003 after several months of cases, Severe Acute Respiratory Syndrome is believed to have possibly started with bats, spread to cats and then to humans in China, followed by 26 other countries, infecting 8,096 people, with 774 deaths.
SARS is characterized by respiratory problems, dry cough, fever and head and body aches and is spread through respiratory droplets from coughs and sneezes.
Quarantine efforts proved effective and by July, the virus was contained and hasn’t reappeared since. China was criticized for trying to suppress information about the virus at the beginning of the outbreak.
SARS was seen by global health professionals as a wake-up call to improve outbreak responses, and lessons from the pandemic were used to keep diseases like H1N1, Ebola and Zika under control.
On March 11, 2020, the World Health Organization announced that the COVID-19 virus was officially a pandemic after barreling through 114 countries in three months and infecting over 118,000 people. And the spread wasn’t anywhere near finished.
COVID-19 is caused by a novel coronavirus—a new coronavirus strain that has not been previously found in people. Symptoms include respiratory problems, fever and cough, and can lead to pneumonia and death. Like SARS, it’s spread through droplets from sneezes.
The first reported case in China appeared November 17, 2019, in the Hubei Province, but went unrecognized. Eight more cases appeared in December with researchers pointing to an unknown virus.
Many learned about COVID-19 when ophthalmologist Dr. Li Wenliang defied government orders and released safety information to other doctors. The following day, China informed WHO and charged Li with a crime. Li died from COVID-19 just over a month later.
Without a vaccine available, the virus spread beyond Chinese borders to nearly every country in the world. By December 2020, it had infected more than 75 million people and led to more than 1.6 million deaths worldwide. The number of new cases was growing faster than ever, with more than 500,000 reported each day on average.
Many people are against vaccinations, and that is their right to feel this way. However, I can’t but feel that they are acting out ignorance. Widespread vaccination has helped decrease or virtually eliminate many dangerous and deadly diseases in the United States. Yet because vaccines have been so effective at removing threats, it’s sometimes difficult to appreciate just how significant they have been to public health.
Here are four major diseases that you may have forgotten about (or downplayed) thanks to how effective vaccines have been at mitigating or eliminating them. (1) Smallpox, (2) Rabies, (4) The Flu.
Smallpox is the only human disease that has been globally eradicated through vaccines. It’s also responsible for the first known vaccine, created by the English physician Edward Jenner in 1796. After observing that milkmaids who caught cowpox (a milder disease) seemed to gain immunity to smallpox, Jenner inoculated an eight-year-old boy using a milkmaid’s cowpox lesion. He then exposed the boy to smallpox, and when the boy didn’t develop any symptoms of the deadly disease, Jenner realized he’d developed a way to prevent it.
Rabies has played a large role in American film and literature—think Old Yeller, To Kill a Mockingbird and Their Eyes Were Watching God. But the deadly disease, which causes erratic behavior, is no longer a major threat in the United States because of vaccines.
In this case, most of the vaccines that have helped save human lives aren’t used on humans—they’re used on other animals that can carry the disease and infect humans by biting them. State rabies programs have guidelines for vaccinating pets and wildlife and tracking animals that might have rabies. Any human who is bitten by an animal, regardless of whether the animal has been vaccinated, must go to a doctor or hospital to receive a rabies vaccine.
Polio was once one of the most feared childhood diseases in the U.S. The viral infection can cause temporary or permanent paralysis, as it did with wheelchair-user Franklin D. Roosevelt. This paralysis could stop a person’s body from breathing on its own, which is why so many infected people had to be placed in an “iron lung.” By the late 1940s, it was disabling more than 35,000 Americans each year. The number of U.S. polio cases peaked in 1952, when it caused 57,879 infections and 3,145 deaths.
During the 1954 trials for Jonas Salk’s polio vaccine, parents flocked to sign their children up to get the shot. As a result, 623,972 children received the vaccine or a placebo. The trials showed the vaccine was 80 to 90 percent effective at preventing polio. Thanks to the continued vaccination of children through today, no polio cases have originated in the United States since 1979. However, polio has not been eradicated, and remains a health threat in Afghanistan and Pakistan.
During the early spread of COVID-19, there was a lot of discussion about whether the infectious disease was serious, or “like the flu”—i.e., not a threat. However, influenza remains a deadly disease that has caused previous pandemics and has the potential to cause future ones as well (Najera speculates the next flu pandemic will happen “sooner rather than later”).
Man is without a doubt the apex predator in this planet, with technology we can extinguish any life form or species, and we have driven countless species into extinction through our careless predation. However, we have been unable to eradicate viruses. we have managed to eliminate a few with vaccinations, but for the most part the vast majority of them still exist and routinely kick our asses. I believe viruses are the worlds way of population control. It seems the greater the incursion into nature, the harder nature fights back. It is humbling to think that something so small can bring civilization to its knees.
Viruses are self limiting, they can only produce and exist in a host. The definition of a virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea. If the host species are totally killed off, the virus dies with it. So for a virus to proliferate, it has to be easily spread and to also not be so deadly that id kills its host before it spreads. It seems viruses have a better understanding of nature than do people. People have been compared to a cancer, because a cancer has not shut off switch. Healthy cells stop growing when they reach a boundary, while cancers spread uncontrollably. Humans behave in much the same way. So the question is who is the apex species in this planet?
history.com, “Pandemics That Changed History,” By History.com editors; newscientist.com, “Did bubonic plague really cause the Black Death?” By Debora Mackenzie;
Did bubonic plague really cause the Black Death?
Everyone thinks the Black Death was caused by bubonic plague. But they could be wrong – and we need to find the real culprit before it strikes again
THE DISEASE that spread like wildfire through Europe between 1347 and 1351 is still the most violent epidemic in recorded history. It killed at least a third of the population, more than 25 million people. Victims first suffered pain, fever and boils, then swollen lymph nodes and blotches on the skin. After that they vomited blood and died within three days. The survivors called it the Great Pestilence. Victorian scientists dubbed it the Black Death.
As far as most people are concerned, the Black Death was bubonic plague, Yersinia pestis, a flea-borne bacterial disease of rodents that jumped to humans. But two epidemiologists from Liverpool University say we’ve got it all wrong. In Biology of Plagues, a book released earlier this year, they effectively demolish the bubonic plague theory. “If you look at how the Black Death spread,” says Susan Scott, one of the authors, “one of the least likely diseases to have caused it is bubonic plague.” If Scott and co-author Christopher Duncan are right, the world would do well to listen.
Whatever pathogen caused the Black Death appears to have ravaged Europe several times during the past two millennia, and it could resurface again. If we knew what it really was, we could prepare for it. “It’s always important to re-evaluate these questions so we are not taken by surprise,” says Steve Morse, an expert on emerging viral diseases at Columbia University in New York. Yet few experts in infectious diseases have even read the book, let alone taken its ideas seriously. New Scientist has, and it looks to us as though Scott and Duncan are on to something.
The idea that the Black Death was bubonic plague dates back to the late 19th century, when Alexandre Yersin, a French bacteriologist, unravelled the complex biology of bubonic plague. He noted that the disease shared a key feature with the Black Death: the bubo, a dark, painful, swollen lymph gland usually in the armpit or groin. Even though buboes also occur in other diseases, he decided the two were the same, even naming the bacterium pestis after the Great Pestilence.
But the theory is riddled with glaring flaws, say Scott and Duncan. First of all, bubonic plague is intimately associated with rodents and the fleas they carry. But the Black Death’s pattern of spread doesn’t fit a rat and flea-borne disease. It raced across the Alps and through northern Europe at temperatures too cold for fleas to hatch, and swept from Marseilles to Paris at four kilometres a day – -far faster than a rat could travel. Moreover, the rats necessary to spread the disease simply were not there. The only rat in Europe in the Middle Ages was the black rat, Rattus rattus, which stays close to human habitation. Yet the Black Death jumped across great tracts of open country-up to 300 kilometres between towns in France-in only a few days with no intermediate outbreaks. “Iceland had no rats at all,” notes Duncan, “but the Black Death was reported there too.”
In contrast, bubonic plague spreads, as rats do, slowly and sporadically. In 1907, the British Plague Commission in India reported an outbreak that took six months to move 300 feet. After bubonic plague arrived in South Africa in 1899, it moved inland at just 20 kilometres a year, even with steam trains to help.
The disease that caused the Black Death stayed in Europe until 1666. During its 300-year reign, Scott and Duncan have found records of outbreaks that occurred somewhere in France virtually every year. Every few years, these outbreaks spawned epidemics that ravaged the rest of Europe. For Yersinia to do this, it would have to become established in a population of rodents that are resistant to the disease. It couldn’t have been rats, because the plague bacterium kills them-along with all other European rodents. As a result, Europe, along with Australia and Antarctica, remain the only regions of the world where bubonic plague has never settled. So, once again, the Black Death behaved in a way plague simply cannot.
Nor is bubonic plague contagious enough to have been the Black Death. The Black Death killed at least a third of the population wherever it hit, sometimes more. But when bubonic plague hit India in the 19th century, fewer than 2 per cent of the people in affected towns died. And when plague invaded southern Africa, South America and the south-western US, it didn’t trigger a massive epidemic.
The most obvious problem with the plague theory is that, unlike bubonic plague, the Black Death obviously spread directly from person to person. People in the thick of the epidemic recognised this, and Scott and Duncan proved they were right by tracing the anatomy of outbreaks, person by person, using English burial records from the 16th century. These records, which detail all deaths from the pestilence by order of Elizabeth I, clearly show the disease spreading from one person to their neighbours and relatives, separated by an incubation period of 20 to 30 days.
The details tally perfectly with a disease that kills about 37 days after infection. For the first 10 to 12 days, you weren’t infectious. Then for 20 to 22 days, you were. You only knew you were infected when you fell ill, for the final five days or less-but by then you had been infecting people unknowingly for weeks. Europeans at the time clearly knew the disease had a long, infectious incubation period, because they rapidly imposed measures to isolate potential carriers. For example, they stopped anyone arriving on a ship from disembarking for 40 days, or quarantina in Italian – -the origin of the word quarantine.
Epidemiologists know that diseases with a long incubation time create outbreaks that last months. From 14th-century ecclesiastical records, Scott and Duncan estimate that outbreaks of the Black Death in a given town or diocese typically lasted 8 or 9 months. That, plus the delay between waves of cases, is the fingerprint of the disease across Europe over seasons and centuries, they say. The pair found exactly the same pattern in 17th-century outbreaks in Florence, Milan and a dozen towns across England, including London, Colchester, Newcastle, Manchester and Eyam in Derbyshire. In 1665, the inhabitants of Eyam selflessly confined themselves to the village. A third of them died, but they kept the disease from reaching other towns. This would not have worked if the carriers were rats.
Despite the force of their argument, Scott and Duncan have yet to convince their colleagues. None of the experts that New Scientist spoke to had read their book, and a summary of its ideas provoked reactions that range from polite interest to outright dismissal. Some of Scott’s colleagues, for example, have scoffed that “everyone knows the Black Death was bubonic plague”.
“I doubt you can say plague was not involved in the Black Death, though there may have been other diseases too,” says Elisabeth Carniel, a bubonic plague expert at the Pasteur Institute in Paris. “But I haven’t had time to read the book.” Carniel suggests that fleas could have spread the Black Death directly between people. Human fleas can keep it in their guts for a few weeks, leading to a delay in spread. But this would be unlikely to have happened the same way every time.
Moreover, people with enough Yersinia in their blood for a flea to pick it up are already very sick. They would only be able to pass their infection on in this way for a very short time-and whoever the flea bit would also sicken within a week, the incubation time of Yersinia. This does not fit the pattern documented by Scott and Duncan. Neither would an extra-virulent Yersinia, which would still depend on rats.
There have been several other ingenious attempts to save the Yersinia theory as inconsistencies have emerged. Many fall back on pneumonic plague, a variant form of Yersinia infection. This can occur in the later stages of bubonic plague, when the bacteria sometimes proliferate in the lungs and can be coughed out, and inhaled by people nearby. Untreated pneumonic plague is invariably fatal and can spread directly from person to person.
But not far, and not for long-plague only becomes pneumonic when the patient is practically at death’s door. “It is simply impossible that people sick enough to have developed the pneumonic form of the disease could have travelled far,” says Scott. Yet the Black Death typically jumped between towns in the time a healthy human took to travel. Also, pneumonic plague kills quickly-within six days, usually less. With such a short infectious period, local outbreaks of pneumonic plague end much sooner than 8 or 9 months, notes Scott. Rats and fleas can restart them, but then the disease is back to spreading slowly and sporadically like flea-borne diseases. Moreover, pneumonic plague lacks the one thing that links Yersinia to the Black Death: buboes.
If the Black Death wasn’t bubonic plague, then what was it? Possibly-and ominously-it may have been a virus. The evidence comes from a mutant protein on the surface of certain white blood cells. The protein, CCR5, normally acts as a receptor for the immune signalling molecules called chemokines, which help control inflammation. The AIDS virus and the poxvirus that causes myxomatosis in rabbits also use CCR5 as a docking port to enter and kill immune cells.
In 1998, a team led by Stephen O’Brien of the US National Cancer Institute analysed a mutant form of CCR5 that gives some protection against HIV. From its pattern of occurrence in the population, they think it arose in north-eastern Europe some 2000 years ago-and around 700 years ago, something happened to boost its incidence from 1 in 40,000 Europeans to 1 in 5. “It had to have been a breathtaking selective pressure to jack it up that high,” says O’Brien. The only plausible explanation, he thinks, is that the mutation helped its carriers survive the Black Death. In fact, say Scott and Duncan, Europeans did seem to grow more resistant to the disease between the 14th and 17th centuries.
Yersinia, too, enters and kills immune cells when it causes disease. But when O’Brien’s team pitted Yersinia against blood cells from people with and without the mutation, they found no dramatic difference. “The results were equivocal,” says O’Brien. “We don’t know if the mutation protected or not.” Further experiments are under way. Similar mutations occur elsewhere in the world, but at nowhere near the high frequency of the European mutant. This suggests that pathogens such as smallpox exerted some selective force, but nothing like whatever happened in Europe, says O’Brien.
The association between CCR5 and viruses suggests that the Black Death was a virus too. Its sudden emergence, and equally sudden disappearance after the Great Plague of London in 1666, also argue for a viral cause. Like the deadly flu of 1918, viruses can sometimes mutate into killers, and then disappear.
But what sort of virus was the Black Death? Scott and Duncan suggest a haemorrhagic filovirus such as Ebola, since the one consistent symptom was bleeding. In fact they think “haemorrhagic plague” would be a good new name for the disease.
They are not the first to blame Ebola for an ancient plague. Scientists and classicists in San Diego reported in 1996 that the symptoms of the plague of Athens around 430 BC, described by Thucydides, are remarkably similar to Ebola, including a distinctive retching or hiccupping. Apart from that, many of the symptoms of that plague- – and one in Constantinople in AD 540 – -were similar to the Black Death.
Of course, the filoviruses we know about are relatively hard to catch, with an incubation period of a week or less, not three weeks or more. But there are other haemorrhagic viruses: Lassa fever in Africa is fairly contagious, and incubates for up to three weeks. Eurasian hantaviruses can incubate for up to 42 days, but are not usually directly contagious between people. Both can be as deadly as the Black Death.
Out of Africa
Perhaps we can narrow the search to Africa. Europeans first recorded the Black Death in Sicily in 1347. The Sicilians blamed it on Genoese galleys that arrived from Crimea just as the illness exploded. But the long incubation period means the infection must have arrived earlier. Scott suspects it initially came from Africa, just a short hop away from Sicily. That continent is historically the home of more human pathogens than any other, and the people who lived through the epidemics that wracked Athens and Constantinople said their disease came from there. The epidemic in Constantinople, for instance, seems to have come via trade routes from the Central African interior. “And I’m sure that disease was the same as the Black Death,” says O’Brien.
One way to solve the puzzle could be to look for the pathogen’s DNA in the plague pits of Europe. Didier Raoult and colleagues at the University of the Mediterranean in Marseilles examined three skeletons in a 14th-century mass grave in Montpellier last year (New Scientist, 11 November 2000, p 31). They searched the skeletons for fragments of DNA unique to several known pathogens-Yersinia, anthrax or typhus. They found one match: Yersinia. In their report they wrote: “We believe that we can end the controversy. Medieval Black Death was [bubonic] plague.”
Not so fast, says Scott. Southern France probably had bubonic plague at that time, even if it wasn’t the Black Death. Moreover, attempts by Alan Cooper, director of the Ancient Biomolecules Centre at Oxford University, and Raoult’s team to replicate the results have so far failed, says Cooper. Similar attempts to find Yersinia DNA at mass graves in London, Copenhagen and another burial in southern France have also failed.
It’s too early to conclude that the failure to find Yersinia DNA means the bacterium wasn’t there, though. The art of retrieving ancient DNA is still in its infancy, Cooper warns. Pathogen DNA – -especially that of fragile viruses – -is extremely difficult to reliably identify in remains that are centuries old. “The pathogen decays along with its victim,” he says. Scientists have had difficulty, for example, in retrieving the 1918 flu virus, even from bodies less than a century old and preserved by permafrost. And even if the technique for retrieving ancient DNA improves, you need to know what you’re searching for. There is no way now to search for an unknown haemorrhagic virus.
But the possibility that the Black Death could strike again should give scientists the incentive to keep trying. The similarity of the catastrophes in Athens, Constantinople and medieval Europe suggests that whatever the pathogen is, it comes out of hiding every few centuries. And the last outbreak was its fastest and most murderous. What would it do in the modern world? Maybe we should find it, before it finds us.
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