Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

HIV's Path Out of Africa: Haiti, the U.S., then the World

30.10.2007
The AIDS virus entered the United States via Haiti, probably arriving in just one person in about 1969, earlier than previously believed, according to new research.

After the virus, HIV-1, entered the U.S., it flourished and spread worldwide.

"Our results show that the strain of virus that spawned the U.S. AIDS epidemic probably arrived in or around 1969. That is earlier than a lot of people had imagined," said senior author Michael Worobey.

The research is the first to definitively pinpoint when and from where HIV-1 entered the United States and shows that most HIV/AIDS viruses in the U.S.

descended from a single common ancestor. The actual ancestral HIV entered the U.S. long before the storied "Patient Zero," Worobey said.

"Haiti was the stepping stone the virus took when it left central Africa and started its sweep around the world," said Worobey, an assistant professor of ecology and evolutionary biology at The University of Arizona in Tucson. "Once the virus got to the U.S., then it just moved explosively around the world."

The strain that migrated to the U.S. in 1969, HIV-1 group M subtype B, is the first human immunodeficiency virus discovered. It is the dominant strain of the AIDS virus in most countries outside sub-Saharan Africa. Almost all the viruses in those countries descended from the one that emerged from Haiti, he said.

Worobey and his colleagues figured out when HIV reached the U.S. by conducting genetic analyses of archived blood samples from early AIDS patients.

Learning more about the genetic make-up of the various strains of HIV could help vaccine development, Worobey said.

The scientists' research paper, "The emergence of HIV/AIDS in the Americas and beyond," is scheduled for publication in the online Early Online edition of the Proceedings of the National Academy of Sciences the week of October 29.

Worobey's co-authors are M. Thomas P. Gilbert of the University of Copenhagen in Denmark; Andrew Rambaut of the University of Edinburgh in Scotland; Gabriela Wlasiuk of the UA; Thomas J. Spira of the Centers for Disease Control and Prevention in Atlanta, Ga.; and Arthur E. Pitchenik of the University of Miami in Fla. The National Institutes of Health, the David and Lucile Packard Foundation and a University Research Fellowship from The Royal Society funded the research.

Figuring out which path HIV/AIDS took as it began its world travels and when it moved from one country to another has long been a topic of scientific investigation and debate.

Worobey and his colleagues tackled the problem by using archived blood samples from AIDS patients to construct genetic family trees for HIV.

The team analyzed blood from five of the first AIDS patients identified in the U.S., all of whom were recent immigrants from Haiti. The team also analyzed genetic sequences from another 117 AIDS patients from around the world who were infected with subtype B, the virus strain that has spread most widely.

Once all the sequences were assembled, the researchers loaded the data into a computer and used Bayesian statistics to investigate all the family trees that were consistent with the genetic data. The researchers then evaluated all possible HIV family trees to determine how probable a particular family tree is.

For the hypothesis that, from Africa, HIV went to the U.S. first, the probability is 0.003 percent -- virtually nil.

For the hypothesis that HIV went from Africa first to Haiti and then on to the U.S., the probability is 99.8 percent, almost 100 percent.

The analysis also shows that the ancestry of most viruses in the U.S. can be traced back to one common ancestor -- the virus that came from Haiti in about 1969.

"Before this study, that had not been nailed down," Worobey said.

The research also reveals that Haiti has a much larger genetic diversity of subtype B than does the U.S.

"The U.S., Australia, Europe plus many countries have just a subset of the subtype B diversity you see in Haiti," Worobey said.

The virus moved from Africa to Haiti in about 1966, he said. Haiti has more diversity of HIV than does the U.S. and other countries because the virus has been there longer and had more time to mutate.

The finding helps explain the early observations of a high prevalence of AIDS in Haiti, Worobey said. "The virus had simply been there longer."

"The main challenge of developing a vaccine against HIV is its tremendous genetic diversity," he said.

Knowing the gamut of diversity within subtype B could be important for effectively developing and testing vaccines that will work in Haiti, Worobey said.

Worobey's next step is following the trail of HIV even further back in time using older archival samples.

Contact info:
Michael Worobey, 520-626-3456, worobey@email.arizona.edu

Mari N. Jensen | The University of Arizona
Further information:
http://uanews.org/
http://www.bi.ku.dk/staff/person.asp?ID=520
http://tree.bio.ed.ac.uk/

More articles from Health and Medicine:

nachricht Researchers release the brakes on the immune system
18.10.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht Norovirus evades immune system by hiding out in rare gut cells
12.10.2017 | University of Pennsylvania School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>