HIV Outbreak Began Decades Earlier Than Thought

[AlaskaDenise]

Rise of cities, risky behavior in west central Africa between 1884 and 1924 at root, study says

Posted October 1, 2008

WEDNESDAY, Oct. 1 (HealthDay News) -- The most pervasive global strain of HIV began spreading in humans around 1900 in sub-Saharan Africa, a new study claims.

The research, which is published in the current issue of Nature, found that HIV began spreading between 1884 and 1924, around the same time urban centers in west central Africa were established. This estimated time of origin is decades earlier than the previous estimate of 1930.

For the study, researchers analyzed tissue samples and uncovered the second-oldest genetic sequence of HIV-1 group M. They used this and other HIV-1 genetic sequences to construct a family tree of the origin of the viral strain and to estimate the time of origin of HIV-1 group M.

The researchers worked with a 1960 sample of HIV gene fragments from a wax-embedded lymph-node tissue biopsy from a woman in Kinshasa in the Democratic Republic of the Congo. This 1960 virus is the second-oldest known HIV-1 group M genetic sequence, with the oldest being a 1959 blood sample from a man also from Kinshasa.

"Previous work on HIV sequencing had been done on frozen samples, and there are only so many of those samples available," lead researcher Michael Worobey, an assistant professor of ecology and evolutionary biology at the University of Arizona in Tucson, said in a university news release.

"From that point on, the next oldest sequences that anyone has recovered are from the late 1970s and 1980s, the era when we knew about AIDS. Now, for the first time, we have been able to compare two relatively ancient HIV strains. That helped us to calibrate how quickly the virus evolved and make some really robust inferences about when it crossed into humans, how quickly the epidemic grew from that time and what factors allowed the virus to enter and become a successful human pathogen," said Worobey.

Previous studies have shown that HIV spread from chimpanzees to humans in southeastern Cameroon.

Worobey said that the HIV epidemic that resulted from the turn-of-the-century spread correlates to the urbanization of colonial Africa, principally the present-day city of Kinshasa in the Democratic Republic of the Congo.

The growth of cities and associated high-risk behaviors may have been a principal cause of the rapid spread of the virus.

Worobey is optimistic about the eventual extinction of the HIV virus.

"I think the picture that has emerged here, where changes the human population experienced may have opened the door to the spread of HIV, is a good reminder that we can make changes now that could help reverse the epidemic. If HIV has one weak spot, it is that it is a relatively poorly transmitted virus. From better testing and prevention, to wider use of the antiretroviral drug therapy, there are a number of ways to reduce transmission and force this virus back into extinction," he said.

http://health.usnews.com/articles/h...break-began-decades-earlier-than-thought.html

 

[Giuseppe]

Re: HIV Outbreak Began Decades Earlier Than Thought

Yes. HIV doesn't transmit itself though aerosols or droplets but only via sexual intercourses or iatrogenic exposures.

Nonetheless, in the early stages of HIV/AIDS pandemic - when the stoppage of spreading was yet achievable - no clear positions and strong commitment were done by national and international authorities; further, bad misinformation - linking HIV with IDU and MSM (with subsequent stigma against these people) impaired effectiveness of risks communication...

 

[Giuseppe]

Re: HIV Outbreak Began Decades Earlier Than Thought

Direct evidence of extensive diversity of HIV-1 in Kinshasa by 1960 [Nature]

Direct evidence of extensive diversity of HIV-1 in Kinshasa by 1960

Nature 455, 661 (2008). doi:10.1038/nature07390

Authors: Michael Worobey, Marlea Gemmel, Dirk E. Teuwen, Tamara Haselkorn, Kevin Kunstman, Michael Bunce, Jean-Jacques Muyembe, Jean-Marie M. Kabongo, Rapha?l M. Kalengayi, Eric Van Marck, M. Thomas P. Gilbert & Steven M. Wolinsky
Human immunodeficiency virus type 1 (HIV-1) sequences that pre-date the recognition of AIDS are critical to defining the time of origin and the timescale of virus evolution.

A viral sequence from 1959 (ZR59) is the oldest known HIV-1 infection.

Other historically documented sequences, important calibration points to convert evolutionary distance into time, are lacking, however; ZR59 is the only one sampled before 1976.

Here we report the amplification and characterization of viral sequences from a Bouin?s-fixed paraffin-embedded lymph node biopsy specimen obtained in 1960 from an adult female in L?opoldville, Belgian Congo (now Kinshasa, Democratic Republic of the Congo (DRC)), and we use them to conduct the first comparative evolutionary genetic study of early pre-AIDS epidemic HIV-1 group M viruses.

Phylogenetic analyses position this viral sequence (DRC60) closest to the ancestral node of subtype A (excluding A2).

Relaxed molecular clock analyses incorporating DRC60 and ZR59 date the most recent common ancestor of the M group to near the beginning of the twentieth century.

The sizeable genetic distance between DRC60 and ZR59 directly demonstrates that diversification of HIV-1 in west-central Africa occurred long before the recognized AIDS pandemic.

The recovery of viral gene sequences from decades-old paraffin-embedded tissues opens the door to a detailed palaeovirological investigation of the evolutionary history of HIV-1 that is not accessible by other methods.
--


View Original Article

 

[Sally Furniss]

Re: HIV Outbreak Began Decades Earlier Than Thought

AIDS Virus May Have Spread to People More Than a Century Ago
By John Lauerman.
<!-- WARNING: #foreach: $wnstory.ATTS: null at /bb/data/web/templates/webmacro_en/washingtonstory.wm:266.2 --> <!-- WARNING: #foreach: $wnstory.ATTS: null at /bb/data/web/templates/webmacro_en/washingtonstory.wm:280.19 --> Oct. 1 (Bloomberg) -- The AIDS virus may have first infected humans in Africa in the late 1800s, half a century earlier than previous estimates and decades before mass migration to cities led to its emergence around the world, scientists said.
Genetic analysis of a tissue sample from Kinshasa in the Democratic Republic of the Congo suggests the lethal virus may have spread from monkeys to humans as early as 1884, said Michael Worobey, leader of an international study appearing tomorrow in the journal Nature. Scientists had earlier estimated the first infection took place in the 1930s.
Viruses and bacteria can lurk in animals for decades before showing their ability to sicken people, said Anthony Fauci, head of the U.S. National Institute of Allergy and Infectious Diseases, which funded the work. In the early days of the AIDS virus, eating infected chimpanzees may have caused several isolated infections that failed to spread, he said.
``Then, the sociological conditions were created that turned some of these blips into an explosion,'' Fauci said Sept. 29 in a telephone interview from his office in Bethesda, Maryland. ``An infected person who goes to a city might give it to commercial sex workers, and then you could have the mushrooming of the epidemic.''
AIDS was first identified in a few U.S. patients in 1981. Today, 33 million people worldwide are infected with HIV, the human immunodeficiency virus that causes it, according to UNAIDS, the United Nations office that coordinates the agency's response to the disease. About 2.7 million people became infected with the virus last year, UNAIDS said in July.
Virus From Chimps
HIV is descended from a chimp virus, and hunters were probably the first humans to come into contact with it, Fauci said. The earliest known infected human tissue sample was obtained in 1959, and is also from the Kinshasa area, he said.
Scientists compared genes from that sample, preserved in wax, with another that had been taken in 1976 to estimate HIV had begun spreading in people in the 1930s. The newly acquired sample from 1960 showed that viruses infecting humans in the same geographical area had already gained a large degree of genetic diversity, said Worobey, an assistant professor in the University of Arizona's department of ecology and evolutionary biology in Tucson.
That diversity took decades to accumulate, suggesting that humans were first infected between 1884 and 1924, Worobey's team said in the study. That coincides with the establishment of urban centers in the region, including Kinshasa in 1881, they said. The city that's now home to 7 million people was founded and named Leopoldville by the explorer Henry Stanley.
Snapshot of Virus
``We've gone from making our best guesses about these events deep in the history of the pandemic to having a direct snapshot,'' Worobey said Sept. 26 in a telephone interview. ``These sequences show the genetic diversity of the virus in 1960. It snaps everything into clear focus.''
Worobey's team, which included scientists from Kinshasa, Australia, Denmark and Belgium, used new techniques to extract DNA from tissues that have been preserved for decades. Preservatives used on the tissues, such as formalin, can break down genetic material, he said.
Worobey began searching Africa for old tissue samples that might contain HIV in 2001. He said that he had just been talking with a colleague about how much more difficult the study was to do than he anticipated, ``and we were laughing about how hard it was.''
To contact the reporter on this story: John Lauerman in Boston at jlauerman@bloomberg.net .
Last Updated: October 1, 2008 13:00 EDT

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