PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

AIDS virus lineage much older than previously thought

If it took thousands of years for SIV to evolve into a primarily non-lethal state, HIV is not likely to follow that route any time soon

AIDS virus lineage much older than previously thought
2010-09-16
(Press-News.org) An ancestor of HIV that infects monkeys is thousands of years older than previously thought, suggesting that HIV, which causes AIDS, is not likely to stop killing humans anytime soon, finds a study by University of Arizona and Tulane University researchers.

The simian immunodeficiency virus, or SIV, is at least 32,000 to 75,000 years old, and likely much older, according to a genetic analysis of unique SIV strains found in monkeys on Bioko Island, a former peninsula that separated from mainland Africa after the Ice Age more than 10,000 years ago. The research, which appears in the Sept. 17 issue of the journal Science, calls into question previous DNA sequencing data that estimated the virus' age at only a few hundred years.

The study results have implications for HIV. SIV, unlike HIV, does not cause AIDS in most of its primate hosts. If it took thousands of years for SIV to evolve into a primarily non-lethal state, it would likely take a very long time for HIV to naturally follow the same trajectory.

"HIV is the odd man out because, by and large, all the other species of immunodeficiency viruses impose a much lower mortality on their host species," said Michael Worobey, a professor in the UA's department of ecology and evolutionary biology, who led the study in conjunction with virologist Preston Marx of Tulane University.

"So, if SIV entered the picture relatively recently as was previously thought, we would think it achieved a much lower virulence over a short timescale," Worobey said. "But our findings suggest the opposite. If HIV is going to evolve to lower virulence, it is unlikely to happen anytime soon."

The study also raises a question about the origin of HIV, which scientists believe evolved from SIV. If humans have been exposed to SIV-infected monkeys for thousands of years, why did the HIV epidemic only begin in the 20th century?

"Something happened in the 20th century to change this relatively benign monkey virus into something that was much more potent and could start the epidemic. We don't know what that flashpoint was, but there had to be one," Marx said.

Finding these virus strains trapped on Bioko Island settles a long-standing debate, Worobey said.

"It's like finding a fossilized piece of virus evolution," he said. "We now have this little island that is revealing clues about SIV, and it says, 'It's old.' Now we know that humans were almost certainly exposed to SIV for a long time, probably hundreds of thousands of years."

"Reconstructing the evolutionary past by comparing the genes of these viruses is like looking out onto the ocean," Worobey said. "You can see a long way, but you don't know what lies beyond the horizon. At some point in the past, you don't know what happened. There is a whole lot of ocean out there that you can't get at with the methods that we have been using in trying to tease apart the relationships among these pathogens."

According to Worobey, SIV was distributed across the African continent before Bioko Island separated from the continent about 10,000 years ago.

"When that happened, whatever viruses were circulating at the time became isolated from the virus populations on mainland Africa," he said.

Marx, a virologist at the Tulane National Primate Research Center, tested his theory that SIV had ancient origins by seeking out DNA samples from monkey populations that had been isolated for thousands of years.

His research team collected bush meat samples from Bioko Drills (Mandrillus leucophaeus). The scientists found four different strains of SIV that were highly genetically divergent from those found on the mainland. Worobey then compared DNA sequences of the viruses with the assumption that the island strains evolved in isolation for more than 10,000 years.

The computer modeling showed the rate of mutation to be much slower than previously thought, indicating that the virus is between 32,000 and 75,000 years old. These dates set a new minimum age for SIV, although it is likely to be even older, Marx said.

Worobey said the study has implications for a lot of rapidly evolving pathogens.

"Our methods are great to describe and predict the short-term changes of viruses like the flu or HIV, but we need to be skeptical of inferences in deep time. We found there is a big disconnect between the rapid evolution for which those pathogens are famous and the incredible degree of conservation we've found."

"Being able to study these viruses in an isolated setting is a unique opportunity," he added.

"As far as we know, there is no other place like Bioko Island," Worobey said. "Nowhere else could we do this kind of deep time calibration. Some of the primate species on Bioko only have a few hundred individuals left and might go extinct in the not-too-distant future. We might not have been able to do this research 10 or 20 years from now."

"Looking into the eyes of these animals and knowing they carry the progenitor of HIV in their bodies sends a shiver down my spine."



INFORMATION:



Funding for Worobey's participation in this research was provided by a grant from the David and Lucile Packard Foundation.


[Attachments] See images for this press release:
AIDS virus lineage much older than previously thought

ELSE PRESS RELEASES FROM THIS DATE:

Scientists report new insights into the moon's rich geologic complexity

2010-09-16
The moon is more geologically complex than previously thought, scientists report Sept. 17 in two papers published in the journal Science. Their conclusion is based on data from the Diviner Lunar Radiometer Experiment aboard NASA's Lunar Reconnaissance Orbiter (LRO), an unmanned mission to comprehensively map the entire moon. The spacecraft orbits some 31 miles above the moon's surface. The new data reveal previously unseen compositional differences in the moon's crustal highlands and have confirmed the presence of material surprisingly abundant in silica — a compound ...

Mediterranean countries offer fewer urban transport options than Central European ones

Mediterranean countries offer fewer urban transport options than Central European ones
2010-09-16
Catalan researchers have studied the factors relating to urban transport service provision in 45 European cities, including Barcelona, Bilbao and Madrid. The study, published in the latest issue of Transportation research part E-logistics and transportation review, concludes that Central European cities have the best urban transport service provision in Europe. Capital cities are at the head of the league, both in terms of supply and demand. "The geographic variables we studied show that Mediterranean countries have the least developed (offer the poorest range) in terms ...

Intensive care diaries protect patients from PTSD

2010-09-16
Some intensive care patients develop post-traumatic stress syndrome (PTSD) after the trauma of a difficult hospital stay, and this is thought to be exacerbated by delusional or fragmentary memories of their time in the intensive care unit. Now researchers writing in BioMed Central's open access journal Critical Care have found that if staff and close relatives make a diary for patients, featuring information about their stay and accompanied by photographs, PTSD rates can be significantly reduced. Professor Richard Griffiths and Christina Jones from the University of Liverpool, ...

Why the craving for cocaine won't go away

2010-09-16
People who have used cocaine run a great risk of becoming addicted, even after long drug-free periods. Now researchers at Linköping University and their colleagues can point to a specific molecule in the brain as a possible target for treatment to prevent relapses. Drugs are addictive because they "hijack" the brain's reward system, which is actually intended to make it pleasurable to eat and have sex, behaviors that are necessary for survival and reproduction. This "hijacking" is extremely long-lived and often leads to relapses into abuse, especially when the individual ...

Technology to screen for synbio abuses lags

2010-09-16
London, UK (September 16, 2010) – Amid growing concern that synthetic life sciences pose biosecurity and biosafety risks, scrutiny is increasing into the burgeoning DNA sequence trade. Research published today in the Bulletin of the Atomic Scientists, published by SAGE, looks at the necessity of a global regulator for DNA trade, and the significant barriers to creating one. Synthetic life sciences are making breakthroughs at a breakneck pace, and could offer technological fixes for our future ecological, technological, and biomedical challenges. But these benefits also ...

The biggest crash on Earth

2010-09-16
During the collision of India with the Eurasian continent, the Indian plate is pushed about 500 kilometers under Tibet, reaching a depth of 250 kilometers. The result of this largest collision in the world is the world's highest mountain range, but the tsunami in the Indian Ocean from 2004 was also created by earthquakes generated by this collision. The clash of the two continents is very complex, the Indian plate, for example, is compressed where it collides with the very rigid plate of the Tarim Basin at the north-western edge of Tibet. On the eastern edge of Tibet, the ...

Goddess of fortune found in Sussita

Goddess of fortune found in Sussita
2010-09-16
A wall painting (fresco) of Tyche, the Greek goddess of fortune, was exposed during the 11th season of excavation at the Sussita site, on the east shore of the Sea of Galilee, which was conducted by researchers of the University of Haifa. Another female figure was found during this season, of a maenad, one of the companions of the wine god Dionysus. "It is interesting to see that although the private residence in which two goddesses were found was in existence during the Byzantine period, when Christianity negated and eradicated idolatrous cults, one can still find clear ...

Cardiac imaging breakthrough developed at the University of Western Ontario

2010-09-16
VIDEO: New imaging technique developed by cardiologist, Dr. James A. White and colleagues at The University of Western Ontario shows 3-D image of the heart vasculature and myocardial scar tissue. Click here for more information. Cardiologists and surgeons may soon have a new tool to improve outcomes for patients requiring pacemakers, bypass surgery or angioplasties. Research led by Dr. James White and his colleagues at The University of Western Ontario has led to a new imaging ...

Discovery of key pathway interaction may lead to therapies that aid brain growth and repair

2010-09-16
WASHINGTON, DC—Researchers at the Center for Neuroscience Research at Children's National Medical Center have discovered that the two major types of signaling pathways activated during brain cell development—the epidermal growth factor receptor pathway and the Notch pathway—operate together to determine how many and which types of brain cells are created during growth and repair in developing and adult brains. This knowledge may help scientists design new ways to induce the brain to repair itself when these signals are interrupted, and indicate a need for further research ...

NASA's 3-D look into Hurricane Igor's heavy rainfall

NASAs 3-D look into Hurricane Igors heavy rainfall
2010-09-16
NASA's Tropical Rainfall Measuring Mission (TRMM) satellite has provided a 3-D look at the power "under the hood" (of clouds) in powerful Category 4 Hurricane Igor as it heads toward Bermuda. In the meantime, Igor is creating dangerous surf in the eastern Atlantic, and it will affect the U.S. East coast later today. Igor is an extremely dangerous category four hurricane on the Saffir-Simpson hurricane wind scale today, Sept. 16, and he is expected to remain a large and powerful hurricane over the next several days. The TRMM satellite, operated by NASA and the Japanese ...

LAST 30 PRESS RELEASES:

Reality check: making indoor smartphone-based augmented reality work

Overthinking what you said? It’s your ‘lizard brain’ talking to newer, advanced parts of your brain

Black men — including transit workers — are targets for aggression on public transportation, study shows

Troubling spike in severe pregnancy-related complications for all ages in Illinois

Alcohol use identified by UTHealth Houston researchers as most common predictor of escalated cannabis vaping among youths in Texas

Need a landing pad for helicopter parenting? Frame tasks as learning

New MUSC Hollings Cancer Center research shows how Golgi stress affects T-cells' tumor-fighting ability

#16to365: New resources for year-round activism to end gender-based violence and strengthen bodily autonomy for all

Earliest fish-trapping facility in Central America discovered in Maya lowlands

São Paulo to host School on Disordered Systems

New insights into sleep uncover key mechanisms related to cognitive function

USC announces strategic collaboration with Autobahn Labs to accelerate drug discovery

Detroit health professionals urge the community to act and address the dangers of antimicrobial resistance

3D-printing advance mitigates three defects simultaneously for failure-free metal parts 

Ancient hot water on Mars points to habitable past: Curtin study

In Patagonia, more snow could protect glaciers from melt — but only if we curb greenhouse gas emissions soon

Simplicity is key to understanding and achieving goals

Caste differentiation in ants

Nutrition that aligns with guidelines during pregnancy may be associated with better infant growth outcomes, NIH study finds

New technology points to unexpected uses for snoRNA

Racial and ethnic variation in survival in early-onset colorectal cancer

Disparities by race and urbanicity in online health care facility reviews

Exploring factors affecting workers' acquisition of exercise habits using machine learning approaches

Nano-patterned copper oxide sensor for ultra-low hydrogen detection

Maintaining bridge safer; Digital sensing-based monitoring system

A novel approach for the composition design of high-entropy fluorite oxides with low thermal conductivity

A groundbreaking new approach to treating chronic abdominal pain

ECOG-ACRIN appoints seven researchers to scientific committee leadership positions

New model of neuronal circuit provides insight on eye movement

Cooking up a breakthrough: Penn engineers refine lipid nanoparticles for better mRNA therapies

[Press-News.org] AIDS virus lineage much older than previously thought
If it took thousands of years for SIV to evolve into a primarily non-lethal state, HIV is not likely to follow that route any time soon