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Another Tick-Borne Disease to Guard Against
By JANE E. BRODY, The New York Times, JULY 30, 2012
Despite its many delights, summer also brings its fair share of pestilence. One, called babesiosis, has only recently been widely recognized as a potentially serious outdoor hazard. According to a very detailed study conducted on Block Island, R.I., it could eventually rival Lyme disease as the most common tick-borne ailment in the United States.
But with reasonable precautions, neither babesiosis nor Lyme should keep you from enjoying a romp in the grass or hike in the woods.
Babesiosis is caused by protozoans that invade red blood cells and can cause a malarialike illness. The disease has an interesting history, recently recounted in The New England Journal of Medicine by Dr. Peter J. Krause, a Yale researcher specializing in tick-borne diseases, and Edouard Vannier, an immunologist at Tufts Medical Center.
Babesiosis (pronounced buh-BEEZ-e-OH-sis) is named for Dr. Victor Babes, a Romanian pathologist who in 1888 identified the disease in cattle that had fever and blood-tainted urine. Until the mid-20th century, the disease was known only in wild and domestic animals, which can be infected by more than 100 different Babesia species.
The first human case was not recognized until 1957. A Croatian herdsman who had no spleen, an important immunological organ, died quickly of the infection, which he most likely acquired from the animals he tended. Twelve years later, the first case in an immunologically normal person was identified on Nantucket Island, and for years the disease was called Nantucket fever.
Unlike Lyme disease, which quickly leapfrogged across the country, babesiosis is spreading slowly through the Northeast and Upper Midwest, where it is increasingly recognized as the cause of a flulike summer ailment. It has been said that Lyme disease moves on the wings of birds, which some experts believe carry the bacteria causing the condition. Babesiosis, however, moves on the backs of mice and deer. Birds do not spread it.
But like the bacteria that cause Lyme disease, Babesia protozoans are transmitted to humans by ticks, which acquire the infection from the white-footed mouse and white-tailed deer. And, yes, the same tick - Ixodes scapularis, popularly called a deer tick - transmits both Lyme disease and babesiosis in this country.
The deer tick, which starts out the size of a poppy seed, requires a blood meal at every one of its developmental stages. With its hind legs clutching grass or a leaf, the tick sits patiently, holding its pincerlike front legs extended, ready to latch onto an unsuspecting mammal that happens by.
In spring or summer, that mammal could be you. In the fall, the adult tick feeds on white-tailed deer, which don't get sick. This feeding allows female ticks to produce a profusion of eggs for the next generation.
Still Uncommon, but Worrisome
"Babesiosis is already a worldwide disease, though the United States has the most cases so far," Dr. Krause said in an interview. "Its geographical distribution is growing, and we think over time it will become increasingly important relative to Lyme disease."
In 2011, the first year of national surveillance, only 1,000 cases of babesiosis were reported. But Dr. Krause's study on Block Island, which tracked the risk of infection among 70 percent of the people living there, revealed that babesiosis was one-third as common as Lyme among those who developed symptoms and nearly as common as Lyme in asymptomatic people.
Underreporting of babesiosis is expected to continue for a long time. People with only mild symptoms are unlikely to see a doctor, and without a telltale sign like the bull's-eye rash of Lyme or a simple blood test for the infection, most doctors are unlikely to diagnose babesiosis correctly, Dr. Krause said.
One-quarter of infected adults and half of infected children were free of symptoms, his study found. Yet if they donated blood, they could transmit the infection to others, with potentially dire consequences. There is no widely used test to screen blood donors for infection with Babesia.
Likewise, an infected woman could transmit the protozoans to her child during pregnancy or delivery.
The risk of a severe and possibly fatal infection is highest in newborns, adults over 50 and anyone with compromised immunity, including people with cancer, H.I.V. or a transplanted organ, and those missing the spleen.
Dr. Krause explained that the spleen "helps to clear organisms in blood that shouldn't be there."
"It produces antibodies that attack the protozoans, which are then gobbled up by macrophages, and it acts like a sieve, screening out Babesia-infected blood cells, which are too big to get through and back into circulation," he said.
Prevention and Treatment
As with Lyme disease, precautions to prevent the bite of a Babesia-bearing tick include staying on cleared trails to minimize contact with leaf litter, brush and tall grass; wearing socks with long pants tucked into them and long-sleeved shirts (not the most pleasant approach on a steamy summer day); and applying repellent to exposed skin and clothing. Products containing DEET can be applied directly to the skin and sprayed on clothing; those containing pyrethrins should be used only on clothing and shoes.
Daily tick checks should be as routine as brushing teeth for people in environments that could harbor ticks. Check everywhere, using mirrors if necessary, including underarms, groin, navel, back of the neck, behind knees, between toes, behind and in ears, and on the scalp.
If a tick is found, without delay use fine-pointed tweezers to grasp it close to the skin and pull upward with steady, even pressure. Do not twist or yank it. Then clean the area and your hands with rubbing alcohol or soap and water.
People who are infected can become ill one to four weeks after a tick bite. Common symptoms include fever, malaise, fatigue, chills and sweats, headache, muscle and joint pain, loss of appetite, cough and nausea. A blood test may reveal anemia.
Certain diagnosis comes from detecting the protozoan in a blood smear. Dr. Krause suggested that labs examine 300 microscopic fields before ruling out the disease.
While the infection clears in some people without treatment, most require a combination of antibiotics, usually atovaquone (Mepron) and azithromycin (Zithromax), for 7 to 10 days. Dr. Krause said even patients with mild symptoms should be treated because they may become severely ill at a later time or spread the infection to others through donated blood.
This post has been revised to reflect the following correction:
Correction: July 30, 2012
An earlier version of this article misstated, using information from The New England Journal of Medicine, the nationality of Dr. Victor Babes. He was Romanian, not Hungarian.
Disease Diagnosed in a 500-Year-Old Mummy
By SINDYA N. BHANOO, The New York Times, July 30, 2012
An Inca girl who lived 500 years ago suffered from a bacterial lung infection just before she died, report scientists who have examined her mummy.
The girl, thought to be 15, was sacrificed by the Andean Inca at the summit of Llullaillaco, a 22,000-foot volcano in the province of Salta, Argentina, said Angelique Corthals, a forensic anthropologist at the City University of New York. The girl had a large sore on one leg, leading Dr. Corthals to believe she may have been unwell when she was buried, alive but unconscious, on the mountain.
Dr. Corthals and her colleagues used a technique called shotgun proteomics to compare proteins found in the mummy against large databases of the human genome. The mummy’s protein profile fit that of someone with a chronic respiratory infection, said Liliana M. Dávalos, an evolutionary biologist at Stony Brook University and another author of the study.
“This is the first time it has been done on an ancient mummy,” Dr. Dávalos said. “It’s now done routinely on cancer patients and has many human disease applications, but it hadn’t been applied in archaeological work.”
Dr. Dávalos and Dr. Corthals and their colleagues report their findings in the journal PLoS One.
Argentine researchers discovered the mummy, along with those of two other sacrificed children, in 1999.
“They were buried in a tomb, and the tomb was packed solid with volcanic ashes and covered in snow, so they did not desiccate,” Dr. Corthals said. “Their entire bodies were sealed and perfectly preserved.”
The sacrificed youths probably made a 3,000-mile journey from Cuzco, the capital of the Inca empire, to the summit, Dr. Corthals said. “The girl actually had gray hair, so I think they knew their fate,” she said. “And the little girl and boy also had their teeth ground down.”
The mummies are on view at the Museum of High Mountain Archaeology in Salta.
Flu That Leapt From Birds to Seals Is Studied for Human Threat
By CARL ZIMMER, The New York Times, July 31, 2012
Four times in the past century, a new strain of flu has emerged that can spread quickly in humans. One of those strains, which emerged in 1918, killed an estimated 50 million people.
All human flu strains evolved from flu viruses that live in birds. To understand how these transitions happen, scientists have recently been tinkering with a strain of bird flu to see how many mutations it takes until its spreads from mammal to mammal.
When news of their efforts emerged last fall, a fierce debate broke out about the wisdom of publishing the experiments in full.
Eventually, the scientists got the go-ahead from a federal advisory board, and earlier this year they described how a few mutations of a strain called H5N1 enabled it to spread among ferrets. But the controversy still rages: Responding to worries about an accidental release of an engineered virus, leading flu scientists agreed in January to a moratorium on further research, and experts are debating when it should be lifted.
Scientists may respect moratoriums, but nature does not. Evolution recently carried out an influenza experiment of its own on the coast of New England. Last fall, 162 dead harbor seal pups washed up on the beaches of New Hampshire and Massachusetts.
In a paper published Tuesday in the journal mBio, a team of scientists reports that the pups were killed by a new strain of influenza. Their research indicates that the virus evolved from bird flu, gaining the ability to spread from seal to seal — a real-life example of the transformation that scientists have been exploring in their labs.
“It’s a beautiful study,” said Eddie Holmes, an expert on flu evolution at Penn State who was not involved in the research. He praised the scientists’ speed in identifying the new virus and convincingly tying it to the seal die-off.
Dr. Holmes believes the new virus needs to be carefully monitored to see what sort of threat, if any, it poses. “The question mark is what it means for seals, and what it means for us,” he said.
Waterfowl like ducks and geese carry a wide range of flu strains. These bird flu viruses sometimes infect mammals, but they rarely, if ever, spread from one mammal to the next.
Since 2003, H5N1, the most worrisome subtype of bird flu, has spread across Asia and Africa. But hospitals have recorded only 607 cases of H5N1 infection in humans.
In rare cases, a bird flu virus strain gains the mutations necessary to multiply quickly inside a mammal and spread to others. Flu viruses have adapted to several mammal species, including pigs, dogs and horses.
In September 2011, beachgoers noticed dead seal pups on New Hampshire beaches. “Surfers were surfing into seals floating in the water,” said Katie Pugliares, a senior biologist with the New England Aquarium’s rescue program.
Unlike typical seal cadavers, the seals were not malnourished, suggesting they had died suddenly.
An examination of tissues from the seals pointed to a respiratory infection. To identify the pathogen, tissue samples from five pups were sent to the Center for Infection and Immunity at Columbia University. Simon Anthony, a postdoctoral researcher at the center, led a search for viral genes in the tissue.
Within 24 hours, Dr. Anthony and his colleagues had discovered that all five seals carried an influenza virus. There have been a few documented flu outbreaks in seals, the most recent having hit in 1992. As far as scientists can tell, these outbreaks came directly from birds; the virus could not spread from mammal to mammal.
Within another 24 hours, the researchers had determined that the virus was a strain of the flu never seen in seals. The virus belongs to a flu subtype known as H3N8. H3N8 viruses have crossed over from birds to dogs and horses several times since 1960.
Dr. Anthony and his colleagues found flu genes at high concentrations in the lining of the seals’ airways. From such evidence, the scientists concluded that H3N8, no innocent bystander, had killed the seals.
“Now we have a nice legal case against this virus,” said W. Ian Lipkin, director of the Center for Infection and Immunity and an author of the study.
The scientists then searched for the origin of the seal virus. Its closest relative is a virus isolated in Ohio in 2002 from a species of duck called the blue-winged teal.
They identified 37 mutations that set the seal virus apart from bird flu. A number of the mutations have been previously documented as important for flu viruses to adapt to mammal hosts.
A new strain that can spread among seals is a reason for serious concern, Dr. Anthony said. “What we fear is that it would allow the virus to persist within the seal population,” he said. “And if it persists, who knows what other changes may accumulate over time?”
“If it adapts better to mammal hosts, it may well start to move into humans,” Dr. Lipkin said. “This is clearly a virus for which we need some surveillance.”
Pigs, Dr. Lipkin noted, are especially good at producing new flu strains because they can be infected by bird flu and mammal flu at the same time. Two kinds of virus can combine, giving rise to new hybrid strains.
Dr. Lipkin and his colleagues found evidence that seal cells can also be invaded by both kinds of viruses — raising the possibility that they could produce new hybrid flu strains as well.
“It could be the equivalent of an aquatic pig,” Dr. Lipkin said.
Dr. Holmes wanted to see more evidence for the idea that flu viruses can mix in seals. He also pointed out that H3N8 has never crossed from dogs or horses to people.
“Just because we find a seal with mammal-adapted H3N8 does not mean we’re going to get a human pandemic,” Dr. Holmes said. “At the moment, it’s hard to say what the threat really is.”
Still, Dr. Pugliares will be on the lookout for a new outbreak in September on the beaches of New England. And she and her colleagues will be taking extra precautions with any seals that show signs of the flu.
“We are going to definitely step it up a notch,” she said.
Artifacts Revive Debate on Transformation of Human Behavior
By JOHN NOBLE WILFORD, The New York Times, July 30, 2012
In the widening search for the origins of modern human evolution, genes and fossils converge on Africa about 200,000 years ago as the where and when of the first skulls and bones that are strikingly similar to ours. So this appears to be the beginning of anatomically modern Homo sapiens.
But evidence for the emergence of behaviorally modern humans is murkier — and controversial. Recent discoveries establish that the Homo sapiens groups who arrived in Europe some 45,000 years ago had already attained the self-awareness, creativity and technology of early modern people. Did this behavior come from Africa after gradual development, or was it an abrupt transition through some profound evolutionary transformation, perhaps caused by hard-to-prove changes in communication by language?
Now, the two schools of thought are clashing again, over new research showing that occupants of Border Cave in southern Africa, who were ancestors of the San Bushmen hunter-gatherers in the area today, were already engaged in relatively modern behavior at least 44,000 years ago, twice as long ago as previously thought. Two teams of scientists reported these findings Monday in the journal Proceedings of the National Academy of Sciences.
Since this early date for the San culture is close to when modern humans first left Africa and reached Europe, proponents of the abrupt-change hypothesis took the findings as good news.
Richard G. Klein, a paleoanthropologist at Stanford University, said in an e-mail from South Africa that the new evidence “supports my view that fully modern hunter-gatherers emerged in Africa abruptly around 50,000 years ago, and I remain convinced that the behavior shift, or advance, underlies the successful expansion of modern Africans to Eurasia.”
Dr. Klein was not an author of either of the papers, but was cited as editor of the main report by a group led by Francesco d’Errico of the University of Bordeaux in France.
In their research, Dr. d’Errico and colleagues re-examined organic artifacts from Border Cave and their refined radiocarbon ages, concluding that “key elements of the San material culture” place “the emergence of modern hunter-gatherer adaptation, as we know it,” to more or less 44,000 years ago.
Previous discoveries revealed that other cave dwellers in southern Africa were experimenting with pigment use, body adornment, and advanced stone and bone tools more than 75,000 years ago, but that many of these artifacts seemed to disappear by 60,000 years ago. Dr. d’Errico’s group said this suggested that “modern behavior appeared in the past and was subsequently lost before becoming firmly established.”
At Border Cave, which lies in South Africa near the border with Swaziland, the international team of scientists analyzed a wealth of organic artifacts in the sequence of their development: bead and shell ornaments; notched bones, perhaps for counting; bone awls; thin bone arrowheads tipped with poison from toxic castor bean oil; and residues of beeswax, resin and possibly egg, which were probably used for hafting wooden handles to stone or bone tools. This may have been one of the earliest known human uses of beeswax.
Regardless of the contending evolutionary interpretations, Chris Stringer, a paleoanthropologist at the Natural History Museum in London, who was not involved in the research, said the evidence from Border Cave provided “the clearest links yet found between Stone Age materials more than 20,000 years old and the culture of extant hunter-gatherers.”
Dr. Stringer said the findings “suggest at least a degree of continuity” in the development of modern human behavior over the last 40,000 years or so.
In a companion article in the journal, researchers led by Paola Villa of the University of Colorado in Boulder described the cave’s stone tools and evidence of changes in hunting technology, including what appeared to be the bow and arrow. Dr. Villa said the contrasting cultures between these people and those who arrived in Europe about this time, leaving graphic traces on cave walls, showed that “the two regions chose very different paths to the evolution of technology and society.”
Asked if the new research strengthened the case for Dr. Klein’s hypothesis, Dr. d’Errico said: “I am not sure it does. Apart from Australia, the spread of modern humans outside Africa is not well documented archaeologically and may have been a more complex process than just a single shot.”
In an earlier paper written with Dr. Stringer, Dr. d’Errico said that in his view, present evidence “does not support a gradualist scenario nor a revolution scenario, but a nonlinear process during which key cultural innovations emerge, are lost and re-emerge in different forms before being finally adopted.”
This process, he continued, “does not happen everywhere at the same time,” and the material culture at Border Cave is “not necessarily valid elsewhere.”
The San people still live in several countries of southern Africa, and until the latter part of the 20th century were still mainly hunter-gatherers. But Dr. Stringer cautioned not to think of them as “living fossils,” unchanged by time. “Their genes, cultures and behaviors have undoubtedly continued to evolve in the intervening millennia,” he said.
By JANE E. BRODY, The New York Times, JULY 30, 2012
Despite its many delights, summer also brings its fair share of pestilence. One, called babesiosis, has only recently been widely recognized as a potentially serious outdoor hazard. According to a very detailed study conducted on Block Island, R.I., it could eventually rival Lyme disease as the most common tick-borne ailment in the United States.
But with reasonable precautions, neither babesiosis nor Lyme should keep you from enjoying a romp in the grass or hike in the woods.
Babesiosis is caused by protozoans that invade red blood cells and can cause a malarialike illness. The disease has an interesting history, recently recounted in The New England Journal of Medicine by Dr. Peter J. Krause, a Yale researcher specializing in tick-borne diseases, and Edouard Vannier, an immunologist at Tufts Medical Center.
Babesiosis (pronounced buh-BEEZ-e-OH-sis) is named for Dr. Victor Babes, a Romanian pathologist who in 1888 identified the disease in cattle that had fever and blood-tainted urine. Until the mid-20th century, the disease was known only in wild and domestic animals, which can be infected by more than 100 different Babesia species.
The first human case was not recognized until 1957. A Croatian herdsman who had no spleen, an important immunological organ, died quickly of the infection, which he most likely acquired from the animals he tended. Twelve years later, the first case in an immunologically normal person was identified on Nantucket Island, and for years the disease was called Nantucket fever.
Unlike Lyme disease, which quickly leapfrogged across the country, babesiosis is spreading slowly through the Northeast and Upper Midwest, where it is increasingly recognized as the cause of a flulike summer ailment. It has been said that Lyme disease moves on the wings of birds, which some experts believe carry the bacteria causing the condition. Babesiosis, however, moves on the backs of mice and deer. Birds do not spread it.
But like the bacteria that cause Lyme disease, Babesia protozoans are transmitted to humans by ticks, which acquire the infection from the white-footed mouse and white-tailed deer. And, yes, the same tick - Ixodes scapularis, popularly called a deer tick - transmits both Lyme disease and babesiosis in this country.
The deer tick, which starts out the size of a poppy seed, requires a blood meal at every one of its developmental stages. With its hind legs clutching grass or a leaf, the tick sits patiently, holding its pincerlike front legs extended, ready to latch onto an unsuspecting mammal that happens by.
In spring or summer, that mammal could be you. In the fall, the adult tick feeds on white-tailed deer, which don't get sick. This feeding allows female ticks to produce a profusion of eggs for the next generation.
Still Uncommon, but Worrisome
"Babesiosis is already a worldwide disease, though the United States has the most cases so far," Dr. Krause said in an interview. "Its geographical distribution is growing, and we think over time it will become increasingly important relative to Lyme disease."
In 2011, the first year of national surveillance, only 1,000 cases of babesiosis were reported. But Dr. Krause's study on Block Island, which tracked the risk of infection among 70 percent of the people living there, revealed that babesiosis was one-third as common as Lyme among those who developed symptoms and nearly as common as Lyme in asymptomatic people.
Underreporting of babesiosis is expected to continue for a long time. People with only mild symptoms are unlikely to see a doctor, and without a telltale sign like the bull's-eye rash of Lyme or a simple blood test for the infection, most doctors are unlikely to diagnose babesiosis correctly, Dr. Krause said.
One-quarter of infected adults and half of infected children were free of symptoms, his study found. Yet if they donated blood, they could transmit the infection to others, with potentially dire consequences. There is no widely used test to screen blood donors for infection with Babesia.
Likewise, an infected woman could transmit the protozoans to her child during pregnancy or delivery.
The risk of a severe and possibly fatal infection is highest in newborns, adults over 50 and anyone with compromised immunity, including people with cancer, H.I.V. or a transplanted organ, and those missing the spleen.
Dr. Krause explained that the spleen "helps to clear organisms in blood that shouldn't be there."
"It produces antibodies that attack the protozoans, which are then gobbled up by macrophages, and it acts like a sieve, screening out Babesia-infected blood cells, which are too big to get through and back into circulation," he said.
Prevention and Treatment
As with Lyme disease, precautions to prevent the bite of a Babesia-bearing tick include staying on cleared trails to minimize contact with leaf litter, brush and tall grass; wearing socks with long pants tucked into them and long-sleeved shirts (not the most pleasant approach on a steamy summer day); and applying repellent to exposed skin and clothing. Products containing DEET can be applied directly to the skin and sprayed on clothing; those containing pyrethrins should be used only on clothing and shoes.
Daily tick checks should be as routine as brushing teeth for people in environments that could harbor ticks. Check everywhere, using mirrors if necessary, including underarms, groin, navel, back of the neck, behind knees, between toes, behind and in ears, and on the scalp.
If a tick is found, without delay use fine-pointed tweezers to grasp it close to the skin and pull upward with steady, even pressure. Do not twist or yank it. Then clean the area and your hands with rubbing alcohol or soap and water.
People who are infected can become ill one to four weeks after a tick bite. Common symptoms include fever, malaise, fatigue, chills and sweats, headache, muscle and joint pain, loss of appetite, cough and nausea. A blood test may reveal anemia.
Certain diagnosis comes from detecting the protozoan in a blood smear. Dr. Krause suggested that labs examine 300 microscopic fields before ruling out the disease.
While the infection clears in some people without treatment, most require a combination of antibiotics, usually atovaquone (Mepron) and azithromycin (Zithromax), for 7 to 10 days. Dr. Krause said even patients with mild symptoms should be treated because they may become severely ill at a later time or spread the infection to others through donated blood.
This post has been revised to reflect the following correction:
Correction: July 30, 2012
An earlier version of this article misstated, using information from The New England Journal of Medicine, the nationality of Dr. Victor Babes. He was Romanian, not Hungarian.
Disease Diagnosed in a 500-Year-Old Mummy
By SINDYA N. BHANOO, The New York Times, July 30, 2012
An Inca girl who lived 500 years ago suffered from a bacterial lung infection just before she died, report scientists who have examined her mummy.
The girl, thought to be 15, was sacrificed by the Andean Inca at the summit of Llullaillaco, a 22,000-foot volcano in the province of Salta, Argentina, said Angelique Corthals, a forensic anthropologist at the City University of New York. The girl had a large sore on one leg, leading Dr. Corthals to believe she may have been unwell when she was buried, alive but unconscious, on the mountain.
Dr. Corthals and her colleagues used a technique called shotgun proteomics to compare proteins found in the mummy against large databases of the human genome. The mummy’s protein profile fit that of someone with a chronic respiratory infection, said Liliana M. Dávalos, an evolutionary biologist at Stony Brook University and another author of the study.
“This is the first time it has been done on an ancient mummy,” Dr. Dávalos said. “It’s now done routinely on cancer patients and has many human disease applications, but it hadn’t been applied in archaeological work.”
Dr. Dávalos and Dr. Corthals and their colleagues report their findings in the journal PLoS One.
Argentine researchers discovered the mummy, along with those of two other sacrificed children, in 1999.
“They were buried in a tomb, and the tomb was packed solid with volcanic ashes and covered in snow, so they did not desiccate,” Dr. Corthals said. “Their entire bodies were sealed and perfectly preserved.”
The sacrificed youths probably made a 3,000-mile journey from Cuzco, the capital of the Inca empire, to the summit, Dr. Corthals said. “The girl actually had gray hair, so I think they knew their fate,” she said. “And the little girl and boy also had their teeth ground down.”
The mummies are on view at the Museum of High Mountain Archaeology in Salta.
Flu That Leapt From Birds to Seals Is Studied for Human Threat
By CARL ZIMMER, The New York Times, July 31, 2012
Four times in the past century, a new strain of flu has emerged that can spread quickly in humans. One of those strains, which emerged in 1918, killed an estimated 50 million people.
All human flu strains evolved from flu viruses that live in birds. To understand how these transitions happen, scientists have recently been tinkering with a strain of bird flu to see how many mutations it takes until its spreads from mammal to mammal.
When news of their efforts emerged last fall, a fierce debate broke out about the wisdom of publishing the experiments in full.
Eventually, the scientists got the go-ahead from a federal advisory board, and earlier this year they described how a few mutations of a strain called H5N1 enabled it to spread among ferrets. But the controversy still rages: Responding to worries about an accidental release of an engineered virus, leading flu scientists agreed in January to a moratorium on further research, and experts are debating when it should be lifted.
Scientists may respect moratoriums, but nature does not. Evolution recently carried out an influenza experiment of its own on the coast of New England. Last fall, 162 dead harbor seal pups washed up on the beaches of New Hampshire and Massachusetts.
In a paper published Tuesday in the journal mBio, a team of scientists reports that the pups were killed by a new strain of influenza. Their research indicates that the virus evolved from bird flu, gaining the ability to spread from seal to seal — a real-life example of the transformation that scientists have been exploring in their labs.
“It’s a beautiful study,” said Eddie Holmes, an expert on flu evolution at Penn State who was not involved in the research. He praised the scientists’ speed in identifying the new virus and convincingly tying it to the seal die-off.
Dr. Holmes believes the new virus needs to be carefully monitored to see what sort of threat, if any, it poses. “The question mark is what it means for seals, and what it means for us,” he said.
Waterfowl like ducks and geese carry a wide range of flu strains. These bird flu viruses sometimes infect mammals, but they rarely, if ever, spread from one mammal to the next.
Since 2003, H5N1, the most worrisome subtype of bird flu, has spread across Asia and Africa. But hospitals have recorded only 607 cases of H5N1 infection in humans.
In rare cases, a bird flu virus strain gains the mutations necessary to multiply quickly inside a mammal and spread to others. Flu viruses have adapted to several mammal species, including pigs, dogs and horses.
In September 2011, beachgoers noticed dead seal pups on New Hampshire beaches. “Surfers were surfing into seals floating in the water,” said Katie Pugliares, a senior biologist with the New England Aquarium’s rescue program.
Unlike typical seal cadavers, the seals were not malnourished, suggesting they had died suddenly.
An examination of tissues from the seals pointed to a respiratory infection. To identify the pathogen, tissue samples from five pups were sent to the Center for Infection and Immunity at Columbia University. Simon Anthony, a postdoctoral researcher at the center, led a search for viral genes in the tissue.
Within 24 hours, Dr. Anthony and his colleagues had discovered that all five seals carried an influenza virus. There have been a few documented flu outbreaks in seals, the most recent having hit in 1992. As far as scientists can tell, these outbreaks came directly from birds; the virus could not spread from mammal to mammal.
Within another 24 hours, the researchers had determined that the virus was a strain of the flu never seen in seals. The virus belongs to a flu subtype known as H3N8. H3N8 viruses have crossed over from birds to dogs and horses several times since 1960.
Dr. Anthony and his colleagues found flu genes at high concentrations in the lining of the seals’ airways. From such evidence, the scientists concluded that H3N8, no innocent bystander, had killed the seals.
“Now we have a nice legal case against this virus,” said W. Ian Lipkin, director of the Center for Infection and Immunity and an author of the study.
The scientists then searched for the origin of the seal virus. Its closest relative is a virus isolated in Ohio in 2002 from a species of duck called the blue-winged teal.
They identified 37 mutations that set the seal virus apart from bird flu. A number of the mutations have been previously documented as important for flu viruses to adapt to mammal hosts.
A new strain that can spread among seals is a reason for serious concern, Dr. Anthony said. “What we fear is that it would allow the virus to persist within the seal population,” he said. “And if it persists, who knows what other changes may accumulate over time?”
“If it adapts better to mammal hosts, it may well start to move into humans,” Dr. Lipkin said. “This is clearly a virus for which we need some surveillance.”
Pigs, Dr. Lipkin noted, are especially good at producing new flu strains because they can be infected by bird flu and mammal flu at the same time. Two kinds of virus can combine, giving rise to new hybrid strains.
Dr. Lipkin and his colleagues found evidence that seal cells can also be invaded by both kinds of viruses — raising the possibility that they could produce new hybrid flu strains as well.
“It could be the equivalent of an aquatic pig,” Dr. Lipkin said.
Dr. Holmes wanted to see more evidence for the idea that flu viruses can mix in seals. He also pointed out that H3N8 has never crossed from dogs or horses to people.
“Just because we find a seal with mammal-adapted H3N8 does not mean we’re going to get a human pandemic,” Dr. Holmes said. “At the moment, it’s hard to say what the threat really is.”
Still, Dr. Pugliares will be on the lookout for a new outbreak in September on the beaches of New England. And she and her colleagues will be taking extra precautions with any seals that show signs of the flu.
“We are going to definitely step it up a notch,” she said.
Artifacts Revive Debate on Transformation of Human Behavior
By JOHN NOBLE WILFORD, The New York Times, July 30, 2012
In the widening search for the origins of modern human evolution, genes and fossils converge on Africa about 200,000 years ago as the where and when of the first skulls and bones that are strikingly similar to ours. So this appears to be the beginning of anatomically modern Homo sapiens.
But evidence for the emergence of behaviorally modern humans is murkier — and controversial. Recent discoveries establish that the Homo sapiens groups who arrived in Europe some 45,000 years ago had already attained the self-awareness, creativity and technology of early modern people. Did this behavior come from Africa after gradual development, or was it an abrupt transition through some profound evolutionary transformation, perhaps caused by hard-to-prove changes in communication by language?
Now, the two schools of thought are clashing again, over new research showing that occupants of Border Cave in southern Africa, who were ancestors of the San Bushmen hunter-gatherers in the area today, were already engaged in relatively modern behavior at least 44,000 years ago, twice as long ago as previously thought. Two teams of scientists reported these findings Monday in the journal Proceedings of the National Academy of Sciences.
Since this early date for the San culture is close to when modern humans first left Africa and reached Europe, proponents of the abrupt-change hypothesis took the findings as good news.
Richard G. Klein, a paleoanthropologist at Stanford University, said in an e-mail from South Africa that the new evidence “supports my view that fully modern hunter-gatherers emerged in Africa abruptly around 50,000 years ago, and I remain convinced that the behavior shift, or advance, underlies the successful expansion of modern Africans to Eurasia.”
Dr. Klein was not an author of either of the papers, but was cited as editor of the main report by a group led by Francesco d’Errico of the University of Bordeaux in France.
In their research, Dr. d’Errico and colleagues re-examined organic artifacts from Border Cave and their refined radiocarbon ages, concluding that “key elements of the San material culture” place “the emergence of modern hunter-gatherer adaptation, as we know it,” to more or less 44,000 years ago.
Previous discoveries revealed that other cave dwellers in southern Africa were experimenting with pigment use, body adornment, and advanced stone and bone tools more than 75,000 years ago, but that many of these artifacts seemed to disappear by 60,000 years ago. Dr. d’Errico’s group said this suggested that “modern behavior appeared in the past and was subsequently lost before becoming firmly established.”
At Border Cave, which lies in South Africa near the border with Swaziland, the international team of scientists analyzed a wealth of organic artifacts in the sequence of their development: bead and shell ornaments; notched bones, perhaps for counting; bone awls; thin bone arrowheads tipped with poison from toxic castor bean oil; and residues of beeswax, resin and possibly egg, which were probably used for hafting wooden handles to stone or bone tools. This may have been one of the earliest known human uses of beeswax.
Regardless of the contending evolutionary interpretations, Chris Stringer, a paleoanthropologist at the Natural History Museum in London, who was not involved in the research, said the evidence from Border Cave provided “the clearest links yet found between Stone Age materials more than 20,000 years old and the culture of extant hunter-gatherers.”
Dr. Stringer said the findings “suggest at least a degree of continuity” in the development of modern human behavior over the last 40,000 years or so.
In a companion article in the journal, researchers led by Paola Villa of the University of Colorado in Boulder described the cave’s stone tools and evidence of changes in hunting technology, including what appeared to be the bow and arrow. Dr. Villa said the contrasting cultures between these people and those who arrived in Europe about this time, leaving graphic traces on cave walls, showed that “the two regions chose very different paths to the evolution of technology and society.”
Asked if the new research strengthened the case for Dr. Klein’s hypothesis, Dr. d’Errico said: “I am not sure it does. Apart from Australia, the spread of modern humans outside Africa is not well documented archaeologically and may have been a more complex process than just a single shot.”
In an earlier paper written with Dr. Stringer, Dr. d’Errico said that in his view, present evidence “does not support a gradualist scenario nor a revolution scenario, but a nonlinear process during which key cultural innovations emerge, are lost and re-emerge in different forms before being finally adopted.”
This process, he continued, “does not happen everywhere at the same time,” and the material culture at Border Cave is “not necessarily valid elsewhere.”
The San people still live in several countries of southern Africa, and until the latter part of the 20th century were still mainly hunter-gatherers. But Dr. Stringer cautioned not to think of them as “living fossils,” unchanged by time. “Their genes, cultures and behaviors have undoubtedly continued to evolve in the intervening millennia,” he said.
