Fragments of 700-year-old DNA from the bug responsible for the Black Death have been pulled from the teeth of four plague victims buried in east London.
Scientists used the degraded strands to reconstruct the entire genetic code of the deadly bacterium - the first time experts have succeeded in drafting the genome of an ancient pathogen, or disease-causing agent.
The researchers found that a specific strain of the plague bug Yersinia pestis caused the pandemic that killed 100 million Europeans - between 30% and 50% of the total population - in just five years between 1347 and 1351.
They also learned that the strain is the "mother" of all modern bubonic plague bacteria.
"Every outbreak across the globe today stems from a descendant of the medieval plague," said lead scientist Dr Hendrik Poinar, from McMaster University in Canada. "With a better understanding of the evolution of this deadly pathogen, we are entering a new era of research into infectious disease."
Although rare, bubonic plague continues to kill some 2,000 people around the world each year.
The scientists, reporting their findings in the journal Nature, analysed the skeletal remains of four individuals exhumed from an East Smithfield "plague pit" sited under what is now the Royal Mint in London.
Tiny scraps of Yersinia pestis DNA were obtained from the victims' dental pulp, and from these fragments, the researchers were able to reconstruct virtually the whole of the bug's genetic code, or genome.
The same techniques could now be used to study the genomes of other ancient pathogens, say experts.
"This will provide us with direct insights into the evolution of human pathogens and historical pandemics," said co-author Dr Johannes Krause, from the University of Tubingen in Germany.
http://www.blogger.com/post-create.g?blogID=4348728589329576621
Showing posts with label Black Death. Show all posts
Showing posts with label Black Death. Show all posts
Thursday, October 13, 2011
Tuesday, January 18, 2011
Fishing nets claim third sea creature
Published: 19/01/2011 at 12:00 AM
Another dolphin has washed up dead on the Gulf of Thailand coast.
It is the third marine creature believed to have drowned in fishing nets in the past two days, officials said.
The body of the young Irrawaddy dolphin was found on a beach in front of a resort in Sam Roi Yot district of Prachuap Khiri Khan yesterday morning. The 1.2-metre-long mammal's body bore deep cuts believed to have been caused by a fishing net.
Local fishery official Chaiya Daotoon said the dolphin had probably died on Monday.
He said the bodies of two other rare sea creatures had come ashore in nearby Chumphon in the past two days.
A 2.3-metre-long hump-backed dolphin was found dead on Monday on Thung Wua Laen beach in Pathiu district of Chumphon and a dead green sea turtle with a 58-centimetre-wide shell was found on Sai Ree beach in Muang district of the same province.
Nipawan Busarawit, director of the Chumphon-based Marine and Coastal Resources Research Centre for the central Gulf of Thailand, said it was common for dead marine animals to come ashore in Chumphon and nearby provinces at this time of year. Six dead dolphins and four dead green sea turtles have washed ashore since November.
Nearly 20 dolphins and green sea turtles were found dead last year. Some were killed by fish nets and intestinal infections. Others bore no trace of damage and officials have not established the cause of their death.
http://www.bangkokpost.com/news/local/217056/fishing-nets-claim-third-sea-creature
Another dolphin has washed up dead on the Gulf of Thailand coast.
It is the third marine creature believed to have drowned in fishing nets in the past two days, officials said.
The body of the young Irrawaddy dolphin was found on a beach in front of a resort in Sam Roi Yot district of Prachuap Khiri Khan yesterday morning. The 1.2-metre-long mammal's body bore deep cuts believed to have been caused by a fishing net.
Local fishery official Chaiya Daotoon said the dolphin had probably died on Monday.
He said the bodies of two other rare sea creatures had come ashore in nearby Chumphon in the past two days.
A 2.3-metre-long hump-backed dolphin was found dead on Monday on Thung Wua Laen beach in Pathiu district of Chumphon and a dead green sea turtle with a 58-centimetre-wide shell was found on Sai Ree beach in Muang district of the same province.
Nipawan Busarawit, director of the Chumphon-based Marine and Coastal Resources Research Centre for the central Gulf of Thailand, said it was common for dead marine animals to come ashore in Chumphon and nearby provinces at this time of year. Six dead dolphins and four dead green sea turtles have washed ashore since November.
Nearly 20 dolphins and green sea turtles were found dead last year. Some were killed by fish nets and intestinal infections. Others bore no trace of damage and officials have not established the cause of their death.
http://www.bangkokpost.com/news/local/217056/fishing-nets-claim-third-sea-creature
Fishing nets claim third sea creature
Published: 19/01/2011 at 12:00 AM
Another dolphin has washed up dead on the Gulf of Thailand coast.
It is the third marine creature believed to have drowned in fishing nets in the past two days, officials said.
The body of the young Irrawaddy dolphin was found on a beach in front of a resort in Sam Roi Yot district of Prachuap Khiri Khan yesterday morning. The 1.2-metre-long mammal's body bore deep cuts believed to have been caused by a fishing net.
Local fishery official Chaiya Daotoon said the dolphin had probably died on Monday.
He said the bodies of two other rare sea creatures had come ashore in nearby Chumphon in the past two days.
A 2.3-metre-long hump-backed dolphin was found dead on Monday on Thung Wua Laen beach in Pathiu district of Chumphon and a dead green sea turtle with a 58-centimetre-wide shell was found on Sai Ree beach in Muang district of the same province.
Nipawan Busarawit, director of the Chumphon-based Marine and Coastal Resources Research Centre for the central Gulf of Thailand, said it was common for dead marine animals to come ashore in Chumphon and nearby provinces at this time of year. Six dead dolphins and four dead green sea turtles have washed ashore since November.
Nearly 20 dolphins and green sea turtles were found dead last year. Some were killed by fish nets and intestinal infections. Others bore no trace of damage and officials have not established the cause of their death.
http://www.bangkokpost.com/news/local/217056/fishing-nets-claim-third-sea-creature
Another dolphin has washed up dead on the Gulf of Thailand coast.
It is the third marine creature believed to have drowned in fishing nets in the past two days, officials said.
The body of the young Irrawaddy dolphin was found on a beach in front of a resort in Sam Roi Yot district of Prachuap Khiri Khan yesterday morning. The 1.2-metre-long mammal's body bore deep cuts believed to have been caused by a fishing net.
Local fishery official Chaiya Daotoon said the dolphin had probably died on Monday.
He said the bodies of two other rare sea creatures had come ashore in nearby Chumphon in the past two days.
A 2.3-metre-long hump-backed dolphin was found dead on Monday on Thung Wua Laen beach in Pathiu district of Chumphon and a dead green sea turtle with a 58-centimetre-wide shell was found on Sai Ree beach in Muang district of the same province.
Nipawan Busarawit, director of the Chumphon-based Marine and Coastal Resources Research Centre for the central Gulf of Thailand, said it was common for dead marine animals to come ashore in Chumphon and nearby provinces at this time of year. Six dead dolphins and four dead green sea turtles have washed ashore since November.
Nearly 20 dolphins and green sea turtles were found dead last year. Some were killed by fish nets and intestinal infections. Others bore no trace of damage and officials have not established the cause of their death.
http://www.bangkokpost.com/news/local/217056/fishing-nets-claim-third-sea-creature
Saturday, January 15, 2011
Legendary Parrot Who Saved His Species Dead at 80
 |
| Photo via AKO AOTEAROA |
Travel & Nature
Richard Henry may sound like an oddly dignified name for a bird -- but its bearer deserves nothing less. Richard was a highly-endangered Kakapo, a flightless parrot from New Zealand, who is credited by many with single-wingedly saving his species. In the 1970s, researchers believed that the Kakapo had been nearly wiped out and that extinction was inevitable -- that is, until they ran across Richard. With his genetic material, conservationists were able to slowly recover the species. But today, after decades of service, Richard Henry has passed away at the ripe old age of 80 -- leaving behind a legacy that, with any luck, will be everlasting.
Aside from being rare, kakapo are actually quite unique for a parrot in that they are nocturnal, flightless, and heavy -- perfect traits for their virtually predator-less native habitat in New Zealand, but those characteristics put them at a terrible disadvantage when Europeans began to settle the islands, bringing animals and a tradition of clearing forests for farmland.
Even early on, scientists at the time noticed that the bird numbers were in decline -- due mainly to the factors described above, but also because they were a curiosity among foreign biologists and animal collectors, though the species didn't fair well in captivity.
By the 1890s, it was clear that lest some action be taken to protect them, the kakapo would soon go the way of that other flightless bird, the dodo. So, the New Zealand government set aside a reserve for the kakapo on the Resolution Island, where they were to be protected from the many threats they faced from humans and other invasive species. Appointed to oversee the birds was a dedicated naturalist by the name of Richard Henry.
Their safety in the reserve was short lived, however; predatory animals were able to swim to the island and decimate the kakapo population there. A small group of birds were rescued and moved to other islands, but the same problems only repeated. Finally, they found some refuge on the island of Fiordland, but their numbers continued to decline well into the 20th century. By the 1970s, it biologists feared they'd become extinct.
Then, on an exploratory expedition to Fiordland in 1975, researchers found a single middle-aged kakapo male, offering hope that the birds could yet be saved -- and they named him after that early kakapo conservationist.
When a small group of other birds were discovered on another island, Richard Henry became instrumental in producing offspring by offering some diversity to the dwindling population.
Over the next few decades later, with the help of Richard Henry, the kakapo species has seen an encouraging increase. Thanks to the dedication of a devout group of conservationists who have worked tirelessly to save the birds -- as well as concerned citizens from throughout the world -- the kakapo population currently stands at 122 birds. And, in the tradition of Richard Henry, each of the birds has a name, too. But his legacy hardly ends there.
With his death at 80 years of age, that very important kakapo leaves behind a better world for his kind. The Department of Conservation's Kākāpō Program Scientist Ron Moorhouse says Richard Henry's death marks the end of an era.
"Richard Henry was a living link to the early days of kākāpō recovery, and perhaps even to a time before stoats when kakapo could boom unmolested in Fiordland," said Dr Moorhouse. Richard Henry had not bred since 1999, and had been showing signs of age including blindness in one eye, slow moving and wrinkles. A sample of his DNA has been preserved.
The kākāpō breeding season is now well under way on both Codfish and Anchor Islands. If chicks are hatched on Anchor, they could well be the first kākāpō chicks in Fiordland since Richard Henry himself was a chick.
We had a great year last year when 33 chicks were born, and we're hoping for more this year. The males are booming well, so we're optimistic. It's sad to lose Richard Henry but the main thing is that the kākāpō population is growing...There's something moving about the story of this bird, so full of tragedy, and hope. Perhaps there was a time when he could sense a darkness closing in on his species, when his lonely calls into the dim forests were all unanswered. But in the end, Richard Henry survived the night and chanced a glimpse of a new beginning for his kind.
It must be a bitter-sweet farewell for those dedicated humans who knew him long, but of course, there's more work to do -- it's egg-laying season for the kakapo soon. And, while Richard Henry's death may mark the end of an era, it marks the beginning of a new one, too.
Thanks to Sirocco Kakapo for the tip.
More on the Kakapo
Teenager on a Mission to Save Endangered Parrots
The World's Most Endangered Parrot Adds 26 Chicks to Its Numbers
Lessons From Extinction: Why are the Dodo Bird and the Kakapo So Similar?
http://www.treehugger.com/files/2011/01/legendary-parrot-who-saved-his-species-dead-at-80.php?campaign=th_rss_travel
Legendary Parrot Who Saved His Species Dead at 80
|
| Photo via AKO AOTEAROA |
Travel & Nature
Richard Henry may sound like an oddly dignified name for a bird -- but its bearer deserves nothing less. Richard was a highly-endangered Kakapo, a flightless parrot from New Zealand, who is credited by many with single-wingedly saving his species. In the 1970s, researchers believed that the Kakapo had been nearly wiped out and that extinction was inevitable -- that is, until they ran across Richard. With his genetic material, conservationists were able to slowly recover the species. But today, after decades of service, Richard Henry has passed away at the ripe old age of 80 -- leaving behind a legacy that, with any luck, will be everlasting.
Aside from being rare, kakapo are actually quite unique for a parrot in that they are nocturnal, flightless, and heavy -- perfect traits for their virtually predator-less native habitat in New Zealand, but those characteristics put them at a terrible disadvantage when Europeans began to settle the islands, bringing animals and a tradition of clearing forests for farmland.
Even early on, scientists at the time noticed that the bird numbers were in decline -- due mainly to the factors described above, but also because they were a curiosity among foreign biologists and animal collectors, though the species didn't fair well in captivity.
By the 1890s, it was clear that lest some action be taken to protect them, the kakapo would soon go the way of that other flightless bird, the dodo. So, the New Zealand government set aside a reserve for the kakapo on the Resolution Island, where they were to be protected from the many threats they faced from humans and other invasive species. Appointed to oversee the birds was a dedicated naturalist by the name of Richard Henry.
Their safety in the reserve was short lived, however; predatory animals were able to swim to the island and decimate the kakapo population there. A small group of birds were rescued and moved to other islands, but the same problems only repeated. Finally, they found some refuge on the island of Fiordland, but their numbers continued to decline well into the 20th century. By the 1970s, it biologists feared they'd become extinct.
Then, on an exploratory expedition to Fiordland in 1975, researchers found a single middle-aged kakapo male, offering hope that the birds could yet be saved -- and they named him after that early kakapo conservationist.
When a small group of other birds were discovered on another island, Richard Henry became instrumental in producing offspring by offering some diversity to the dwindling population.
Over the next few decades later, with the help of Richard Henry, the kakapo species has seen an encouraging increase. Thanks to the dedication of a devout group of conservationists who have worked tirelessly to save the birds -- as well as concerned citizens from throughout the world -- the kakapo population currently stands at 122 birds. And, in the tradition of Richard Henry, each of the birds has a name, too. But his legacy hardly ends there.
With his death at 80 years of age, that very important kakapo leaves behind a better world for his kind. The Department of Conservation's Kākāpō Program Scientist Ron Moorhouse says Richard Henry's death marks the end of an era.
"Richard Henry was a living link to the early days of kākāpō recovery, and perhaps even to a time before stoats when kakapo could boom unmolested in Fiordland," said Dr Moorhouse. Richard Henry had not bred since 1999, and had been showing signs of age including blindness in one eye, slow moving and wrinkles. A sample of his DNA has been preserved.
The kākāpō breeding season is now well under way on both Codfish and Anchor Islands. If chicks are hatched on Anchor, they could well be the first kākāpō chicks in Fiordland since Richard Henry himself was a chick.
We had a great year last year when 33 chicks were born, and we're hoping for more this year. The males are booming well, so we're optimistic. It's sad to lose Richard Henry but the main thing is that the kākāpō population is growing...There's something moving about the story of this bird, so full of tragedy, and hope. Perhaps there was a time when he could sense a darkness closing in on his species, when his lonely calls into the dim forests were all unanswered. But in the end, Richard Henry survived the night and chanced a glimpse of a new beginning for his kind.
It must be a bitter-sweet farewell for those dedicated humans who knew him long, but of course, there's more work to do -- it's egg-laying season for the kakapo soon. And, while Richard Henry's death may mark the end of an era, it marks the beginning of a new one, too.
Thanks to Sirocco Kakapo for the tip.
More on the Kakapo
Teenager on a Mission to Save Endangered Parrots
The World's Most Endangered Parrot Adds 26 Chicks to Its Numbers
Lessons From Extinction: Why are the Dodo Bird and the Kakapo So Similar?
http://www.treehugger.com/files/2011/01/legendary-parrot-who-saved-his-species-dead-at-80.php?campaign=th_rss_travel
Tuesday, November 2, 2010
Genetics of the Black Death
Europe's Plagues Came From China, Study Finds
By NICHOLAS WADE
The great waves of plague that twice devastated Europe and changed the course of history had their origins in China, a team of medical geneticists reported Sunday, as did a third plague outbreak that struck less harmfully in the 19th century.
And in separate research, a team of biologists reported conclusively this month that the causative agent of the most deadly plague, the Black Death, was the bacterium known as Yersinia pestis. This agent had always been the favored cause, but a vigorous minority of biologists and historians have argued the Black Death differed from modern cases of plague studied in India, and therefore must have had adifferent cause.
The Black Death began in Europe in 1347 and carried off an estimated 30 percent or more of the population of Europe. For centuries the epidemic continued to strike every 10 years or so, its last major outbreak being the Great Plague of London from 1665 to 1666. The disease is spread by rats and transmitted to people by fleas or, in some cases, directly by breathing.
One team of biologists, led by Barbara Bramanti of the Institut Pasteur in Paris and Stephanie Haensch of Johannes Gutenberg University in Germany, analyzed ancient DNA and proteins from plague pits, the mass burial grounds across Europe in which the dead were interred. Writing in the journal PLoS Pathogens this month, they say their findings put beyond doubt that the Black Death was brought aboutby Yersinia pestis.
Dr. Bramanti's team was able to distinguish two strains of the Black Death plague bacterium, which differ both from each other and from thethree principal strains in the world today. They infer that medieval Europe must have been invaded by two different sources of Yersinia pestis. One strain reached the port of Marseilles on France's southern coast in 1347, spread rapidly across France and by 1349 had reached Hereford, a busy English market town and pilgrimage center near the Welsh border.
The strain of bacterium analyzed from the bones and teeth of a Hereford plague pit dug in 1349 is identical to that from a plague pitof 1348 in southern France, suggesting a direct route of travel. But a plague pit in the Dutch town of Bergen op Zoom has bacteria of a different strain, which the researchers infer arrived from Norway.
The Black Death is the middle of three great waves of plague that have hit in historical times. The first appeared in the 6th century during the reign of the Byzantine emperor Justinian, reaching his capital,
Constantinople, on grain ships from Egypt. The Justinian plague, as historians call it, is thought to have killed perhaps half the population of Europe and to have eased the Arab takeover of Byzantine provinces in the Near East and Africa.
The third great wave of plague began in China's Yunnan province in 1894, emerged in Hong Kong and then spread via shipping routes throughout the world. It reached the United States through a plague ship from Hong Kong that docked at Hawaii, where plague broke out in December 1899, and then San Francisco, whose plague epidemic began in March 1900.
The three plague waves have now been tied together in common family tree by a team of medical geneticists led by Mark Achtman of University College Cork in Ireland. By looking at genetic variations in living strains of Yersinia pestis, Dr. Achtman's team has reconstructed a family tree of the bacterium. By counting the number of genetic changes, which clock up at a generally steady rate, they have dated the branch points of the tree, which enables the major branches to be correlated with historical events.
In the issue of Nature Genetics published online Sunday, they concludethat all three of the great waves of plague originated from China, where the root of their tree is situated. Plague would have reached Europe across the Silk Road, they say. An epidemic of plague that reached East Africa was probably spread by the voyages of the Chinese admiral Zheng He who led a fleet of 300 ships to Africa in 1409.
"What's exciting is that we are able to reconstruct the historical routes of bacterial disease over centuries," Dr. Achtman said.
Lester K. Little, an expert on the Justinian plague at Smith College, said in an interview from Bergamo, Italy, that the epidemic was first reported by the Byzantine historian Procopius in 541 A.D. from the ancient port of Pelusium, near Suez in Egypt. Historians had assumed it arrived there from the Red Sea or Africa, but the Chinese origin now suggested by the geneticists is possible, Dr. Little said.
The geneticists' work is "immensely impressive," Dr. Little said, and adds a third leg to the studies of plague by historians and by archaeologists.
The likely origin of the plague in China has nothing to do with its people or crowded cities, Dr. Achtman said. The bacterium has no interest in people, whom it slaughters by accident. Its natural hosts are various species of rodent such as marmots and voles, which are found throughout China.
http://www.nytimes.com/2010/11/01/health/01plague.html
By NICHOLAS WADE
The great waves of plague that twice devastated Europe and changed the course of history had their origins in China, a team of medical geneticists reported Sunday, as did a third plague outbreak that struck less harmfully in the 19th century.
And in separate research, a team of biologists reported conclusively this month that the causative agent of the most deadly plague, the Black Death, was the bacterium known as Yersinia pestis. This agent had always been the favored cause, but a vigorous minority of biologists and historians have argued the Black Death differed from modern cases of plague studied in India, and therefore must have had adifferent cause.
The Black Death began in Europe in 1347 and carried off an estimated 30 percent or more of the population of Europe. For centuries the epidemic continued to strike every 10 years or so, its last major outbreak being the Great Plague of London from 1665 to 1666. The disease is spread by rats and transmitted to people by fleas or, in some cases, directly by breathing.
One team of biologists, led by Barbara Bramanti of the Institut Pasteur in Paris and Stephanie Haensch of Johannes Gutenberg University in Germany, analyzed ancient DNA and proteins from plague pits, the mass burial grounds across Europe in which the dead were interred. Writing in the journal PLoS Pathogens this month, they say their findings put beyond doubt that the Black Death was brought aboutby Yersinia pestis.
Dr. Bramanti's team was able to distinguish two strains of the Black Death plague bacterium, which differ both from each other and from thethree principal strains in the world today. They infer that medieval Europe must have been invaded by two different sources of Yersinia pestis. One strain reached the port of Marseilles on France's southern coast in 1347, spread rapidly across France and by 1349 had reached Hereford, a busy English market town and pilgrimage center near the Welsh border.
The strain of bacterium analyzed from the bones and teeth of a Hereford plague pit dug in 1349 is identical to that from a plague pitof 1348 in southern France, suggesting a direct route of travel. But a plague pit in the Dutch town of Bergen op Zoom has bacteria of a different strain, which the researchers infer arrived from Norway.
The Black Death is the middle of three great waves of plague that have hit in historical times. The first appeared in the 6th century during the reign of the Byzantine emperor Justinian, reaching his capital,
Constantinople, on grain ships from Egypt. The Justinian plague, as historians call it, is thought to have killed perhaps half the population of Europe and to have eased the Arab takeover of Byzantine provinces in the Near East and Africa.
The third great wave of plague began in China's Yunnan province in 1894, emerged in Hong Kong and then spread via shipping routes throughout the world. It reached the United States through a plague ship from Hong Kong that docked at Hawaii, where plague broke out in December 1899, and then San Francisco, whose plague epidemic began in March 1900.
The three plague waves have now been tied together in common family tree by a team of medical geneticists led by Mark Achtman of University College Cork in Ireland. By looking at genetic variations in living strains of Yersinia pestis, Dr. Achtman's team has reconstructed a family tree of the bacterium. By counting the number of genetic changes, which clock up at a generally steady rate, they have dated the branch points of the tree, which enables the major branches to be correlated with historical events.
In the issue of Nature Genetics published online Sunday, they concludethat all three of the great waves of plague originated from China, where the root of their tree is situated. Plague would have reached Europe across the Silk Road, they say. An epidemic of plague that reached East Africa was probably spread by the voyages of the Chinese admiral Zheng He who led a fleet of 300 ships to Africa in 1409.
"What's exciting is that we are able to reconstruct the historical routes of bacterial disease over centuries," Dr. Achtman said.
Lester K. Little, an expert on the Justinian plague at Smith College, said in an interview from Bergamo, Italy, that the epidemic was first reported by the Byzantine historian Procopius in 541 A.D. from the ancient port of Pelusium, near Suez in Egypt. Historians had assumed it arrived there from the Red Sea or Africa, but the Chinese origin now suggested by the geneticists is possible, Dr. Little said.
The geneticists' work is "immensely impressive," Dr. Little said, and adds a third leg to the studies of plague by historians and by archaeologists.
The likely origin of the plague in China has nothing to do with its people or crowded cities, Dr. Achtman said. The bacterium has no interest in people, whom it slaughters by accident. Its natural hosts are various species of rodent such as marmots and voles, which are found throughout China.
http://www.nytimes.com/2010/11/01/health/01plague.html
Genetics of the Black Death
Europe's Plagues Came From China, Study Finds
By NICHOLAS WADE
The great waves of plague that twice devastated Europe and changed the course of history had their origins in China, a team of medical geneticists reported Sunday, as did a third plague outbreak that struck less harmfully in the 19th century.
And in separate research, a team of biologists reported conclusively this month that the causative agent of the most deadly plague, the Black Death, was the bacterium known as Yersinia pestis. This agent had always been the favored cause, but a vigorous minority of biologists and historians have argued the Black Death differed from modern cases of plague studied in India, and therefore must have had adifferent cause.
The Black Death began in Europe in 1347 and carried off an estimated 30 percent or more of the population of Europe. For centuries the epidemic continued to strike every 10 years or so, its last major outbreak being the Great Plague of London from 1665 to 1666. The disease is spread by rats and transmitted to people by fleas or, in some cases, directly by breathing.
One team of biologists, led by Barbara Bramanti of the Institut Pasteur in Paris and Stephanie Haensch of Johannes Gutenberg University in Germany, analyzed ancient DNA and proteins from plague pits, the mass burial grounds across Europe in which the dead were interred. Writing in the journal PLoS Pathogens this month, they say their findings put beyond doubt that the Black Death was brought aboutby Yersinia pestis.
Dr. Bramanti's team was able to distinguish two strains of the Black Death plague bacterium, which differ both from each other and from thethree principal strains in the world today. They infer that medieval Europe must have been invaded by two different sources of Yersinia pestis. One strain reached the port of Marseilles on France's southern coast in 1347, spread rapidly across France and by 1349 had reached Hereford, a busy English market town and pilgrimage center near the Welsh border.
The strain of bacterium analyzed from the bones and teeth of a Hereford plague pit dug in 1349 is identical to that from a plague pitof 1348 in southern France, suggesting a direct route of travel. But a plague pit in the Dutch town of Bergen op Zoom has bacteria of a different strain, which the researchers infer arrived from Norway.
The Black Death is the middle of three great waves of plague that have hit in historical times. The first appeared in the 6th century during the reign of the Byzantine emperor Justinian, reaching his capital,
Constantinople, on grain ships from Egypt. The Justinian plague, as historians call it, is thought to have killed perhaps half the population of Europe and to have eased the Arab takeover of Byzantine provinces in the Near East and Africa.
The third great wave of plague began in China's Yunnan province in 1894, emerged in Hong Kong and then spread via shipping routes throughout the world. It reached the United States through a plague ship from Hong Kong that docked at Hawaii, where plague broke out in December 1899, and then San Francisco, whose plague epidemic began in March 1900.
The three plague waves have now been tied together in common family tree by a team of medical geneticists led by Mark Achtman of University College Cork in Ireland. By looking at genetic variations in living strains of Yersinia pestis, Dr. Achtman's team has reconstructed a family tree of the bacterium. By counting the number of genetic changes, which clock up at a generally steady rate, they have dated the branch points of the tree, which enables the major branches to be correlated with historical events.
In the issue of Nature Genetics published online Sunday, they concludethat all three of the great waves of plague originated from China, where the root of their tree is situated. Plague would have reached Europe across the Silk Road, they say. An epidemic of plague that reached East Africa was probably spread by the voyages of the Chinese admiral Zheng He who led a fleet of 300 ships to Africa in 1409.
"What's exciting is that we are able to reconstruct the historical routes of bacterial disease over centuries," Dr. Achtman said.
Lester K. Little, an expert on the Justinian plague at Smith College, said in an interview from Bergamo, Italy, that the epidemic was first reported by the Byzantine historian Procopius in 541 A.D. from the ancient port of Pelusium, near Suez in Egypt. Historians had assumed it arrived there from the Red Sea or Africa, but the Chinese origin now suggested by the geneticists is possible, Dr. Little said.
The geneticists' work is "immensely impressive," Dr. Little said, and adds a third leg to the studies of plague by historians and by archaeologists.
The likely origin of the plague in China has nothing to do with its people or crowded cities, Dr. Achtman said. The bacterium has no interest in people, whom it slaughters by accident. Its natural hosts are various species of rodent such as marmots and voles, which are found throughout China.
http://www.nytimes.com/2010/11/01/health/01plague.html
By NICHOLAS WADE
The great waves of plague that twice devastated Europe and changed the course of history had their origins in China, a team of medical geneticists reported Sunday, as did a third plague outbreak that struck less harmfully in the 19th century.
And in separate research, a team of biologists reported conclusively this month that the causative agent of the most deadly plague, the Black Death, was the bacterium known as Yersinia pestis. This agent had always been the favored cause, but a vigorous minority of biologists and historians have argued the Black Death differed from modern cases of plague studied in India, and therefore must have had adifferent cause.
The Black Death began in Europe in 1347 and carried off an estimated 30 percent or more of the population of Europe. For centuries the epidemic continued to strike every 10 years or so, its last major outbreak being the Great Plague of London from 1665 to 1666. The disease is spread by rats and transmitted to people by fleas or, in some cases, directly by breathing.
One team of biologists, led by Barbara Bramanti of the Institut Pasteur in Paris and Stephanie Haensch of Johannes Gutenberg University in Germany, analyzed ancient DNA and proteins from plague pits, the mass burial grounds across Europe in which the dead were interred. Writing in the journal PLoS Pathogens this month, they say their findings put beyond doubt that the Black Death was brought aboutby Yersinia pestis.
Dr. Bramanti's team was able to distinguish two strains of the Black Death plague bacterium, which differ both from each other and from thethree principal strains in the world today. They infer that medieval Europe must have been invaded by two different sources of Yersinia pestis. One strain reached the port of Marseilles on France's southern coast in 1347, spread rapidly across France and by 1349 had reached Hereford, a busy English market town and pilgrimage center near the Welsh border.
The strain of bacterium analyzed from the bones and teeth of a Hereford plague pit dug in 1349 is identical to that from a plague pitof 1348 in southern France, suggesting a direct route of travel. But a plague pit in the Dutch town of Bergen op Zoom has bacteria of a different strain, which the researchers infer arrived from Norway.
The Black Death is the middle of three great waves of plague that have hit in historical times. The first appeared in the 6th century during the reign of the Byzantine emperor Justinian, reaching his capital,
Constantinople, on grain ships from Egypt. The Justinian plague, as historians call it, is thought to have killed perhaps half the population of Europe and to have eased the Arab takeover of Byzantine provinces in the Near East and Africa.
The third great wave of plague began in China's Yunnan province in 1894, emerged in Hong Kong and then spread via shipping routes throughout the world. It reached the United States through a plague ship from Hong Kong that docked at Hawaii, where plague broke out in December 1899, and then San Francisco, whose plague epidemic began in March 1900.
The three plague waves have now been tied together in common family tree by a team of medical geneticists led by Mark Achtman of University College Cork in Ireland. By looking at genetic variations in living strains of Yersinia pestis, Dr. Achtman's team has reconstructed a family tree of the bacterium. By counting the number of genetic changes, which clock up at a generally steady rate, they have dated the branch points of the tree, which enables the major branches to be correlated with historical events.
In the issue of Nature Genetics published online Sunday, they concludethat all three of the great waves of plague originated from China, where the root of their tree is situated. Plague would have reached Europe across the Silk Road, they say. An epidemic of plague that reached East Africa was probably spread by the voyages of the Chinese admiral Zheng He who led a fleet of 300 ships to Africa in 1409.
"What's exciting is that we are able to reconstruct the historical routes of bacterial disease over centuries," Dr. Achtman said.
Lester K. Little, an expert on the Justinian plague at Smith College, said in an interview from Bergamo, Italy, that the epidemic was first reported by the Byzantine historian Procopius in 541 A.D. from the ancient port of Pelusium, near Suez in Egypt. Historians had assumed it arrived there from the Red Sea or Africa, but the Chinese origin now suggested by the geneticists is possible, Dr. Little said.
The geneticists' work is "immensely impressive," Dr. Little said, and adds a third leg to the studies of plague by historians and by archaeologists.
The likely origin of the plague in China has nothing to do with its people or crowded cities, Dr. Achtman said. The bacterium has no interest in people, whom it slaughters by accident. Its natural hosts are various species of rodent such as marmots and voles, which are found throughout China.
http://www.nytimes.com/2010/11/01/health/01plague.html
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