Friday, October 23, 2015

Plague spread 3,000 years earlier than 1st thought: 2,800 BC

Associated Press
In this undated photo released by Cell journal, the Sope I grave in Estonia, where plague DNA was found in a tooth from this individual and is the earliest evidence of plague found in Europe.  The plague was spreading nearly 3,000-years before previously thought, according to findings published Thursday Oct. 22, 2015, in the journal Cell.  Scientists have found traces of the disease in the teeth of ancient people, although the Bronze Age plague revealed by the new study seems to have lacked the ability to spread over wide regions, so probably remained in local pockets of disease.  (Harri Moora / Cell 2015 via AP)
LONDON (AP) — The plague was spreading nearly 3,000 years before previously thought, scientists say after finding traces of the disease in the teeth of ancient people — a discovery that could provide clues to how dangerous diseases evolve.
To find evidence of the prehistoric infection, researchers drilled into the teeth of 101 individuals who lived in Central Asia and Europe some 2,800 to 5,000 years ago. The drilling produced a powder that the researchers examined for DNA from plague bacteria. They found it in samples from seven people.
Before the study, the earliest evidence of the plague was from A.D. 540, said Simon Rasmussen of the Technical University of Denmark. He and colleagues found it as early as 2,800 B.C.
"We were very surprised to find it 3,000 years before it was supposed to exist," said Rasmussen, one of the study authors. The research was published online Thursday in the journal, Cell.
Rasmussen said the plague they found was a different strain from the one that caused the three known pandemics, including the Black Death that swept across Medieval Europe. In contrast to later strains, including the one estimated to have wiped out about half of Europe, the Bronze Age plague revealed by the new study could not be spread by fleas because it lacked a crucial gene. So it was probably less able to infect people over wide regions.
But Rasmussen said knowing that plague existed thousands of years earlier than had been believed might explain some unsolved historical mysteries, including the "Plague of Athens," a horrifying unknown epidemic that struck the Greek capital in 430 B.C. It killed up to 100,000 people during the Peloponnesian War.
"People have been speculating about what this was, like was this measles or typhus, but it could well have been plague," Rasmussen said.
He said tracking how the plague evolved from being an intestinal infection to "one of the most deadly diseases ever encountered by humans" could help scientists predict the disease's future path.
"Typically, things get less virulent with time, but that's not always the case," said Hendrik Poinar, a molecular evolutionary geneticist at McMaster University in Canada who was not part of the study. He noted that diseases could acquire new features — including lethality — relatively quickly.
Other experts said it was unlikely that plague would ever pose as great a threat as it has in the past, especially since it is now largely treatable.
"It might be that (plague) will eventually burn itself out," said Brendan Wren, dean of the faculty of infectious and tropical diseases at the London School of Hygiene and Tropical Medicine. Wren said other diseases like leprosy have also lost genes over time and are now less able to sicken people.
"The evidence is that (plague) is not going to come back big time, but it's hard to predict what the bacteria will do," he said. "They are great survivors."

Wednesday, October 14, 2015

Scientists find earliest evidence of mammalian hair

Researchers say the animal's abnormally shortened hairs suggest the presence of a fungal skin infection.
By Brooks Hays   |   Oct. 14, 2015 at 5:13 PM
The Spinolestes xenarthrosus fossil was recovered from a limestone deposit near Cuenca, Spain. Photo by Bonn University/Nature
BON, Germany, Oct. 14 (UPI) -- A new study suggests a 125-million-year-old rodent fossil, recently found and remarkably well preserved, showcases of the evolutionary potential of early mammals.
The Spinolestes xenarthrosus fossil, unearthed in Spain, features the earliest-yet evidence of mammalian hair, an external ear lobe and soft tissues of the liver, lung and diaphragm.
The discovery is detailed in an online paper, published this week in the journal Nature.
"Spinolestes is a spectacular find. It is stunning to see almost perfectly preserved skin and hair structures fossilized in microscopic detail in such an old fossil," study co-author Zhe-Xi Luo, professor of organismal biology and anatomy at the University of Chicago, said in a press release. "This Cretaceous furball displays the entire structural diversity of modern mammalian skin and hairs."
An international team of researchers from Chicago, Germany and Spain believe the rat-like creature was quickly and neatly preserved in a process called phosphatic fossilization, whereby the decaying animal is quickly enveloped by phosphate-emitting microbes.
The process preserved hair follicles as well as a spine-like bulbs, similar to the spikes that adorn modern day porcupines.
"We are familiar with these characteristics in modern spiny mice from Africa and Asia Minor," explained Thomas Martin, a paleontologist at the University of Bonn, in Germany. "If a predator grabs them by the back, the spines detach from the skin. The mouse can escape and the attacker is left with nothing more than a mouthful of spines."
Researchers say the animal's abnormally shortened hairs suggest the presence of a fungal skin infection called dermatophytosis, common among modern mammals -- evidence that ancient animals may suffered from many of the same diseases present today.
Also unique is the creature's spine. Its interlocking appendages made it especially strong.
"Similar structures are found today in armadillos and anteaters but also in the African hero shrew," Martin said. "For instance, the hero shrew uses its strong back to break off palm fronds from the trunk of the tree. In this way, it can reach insect larvae living between the attachment points of the fronds and the trunk."
Though mammals living alongside the dinosaurs were rather small, they weren't primitive. The new findings suggest many of the evolutionary adaptations that helped mammals later flourish were already present during the early Cretaceous.