Showing posts with label HIV strain. Show all posts
Showing posts with label HIV strain. Show all posts

Wednesday, February 29, 2012

The West's Influence on the Spread of AIDS

viaNPRbooks

A woman walks past a banner placed around the perimeter of the Rand Afrikaans University in Johannesburg on World AIDS Day. The university used the banner to raise public awareness about AIDS and the devastating toll the disease has had in South Africa. HIV is a slow-moving time bomb.

Unlike Ebola, which infects and kills people quickly — and then disappears just as quickly — the HIV epidemic has become so good at killing people in part because it moves so very slowly, says journalist Craig Timberg.

"In vaginal sex, you can have sex with hundreds of people and not transmit [HIV], it turns out," he says. "And that's part of the reason it's still with us today. It has spread very slowly. It makes people ill very slowly. ... And that's one of the reasons why it's been so difficult for the world to understand it. ... It's been hard to make sense of this epidemic because of the way it moves. It's not obvious."

Timberg, the former Johannesburg bureau chief for The Washington Post, with his co-author Daniel Halperin, an AIDS expert currently at the University of North Carolina, explores the history of the HIV virus and efforts to fight the AIDS epidemic in his book Tinderbox: How the West Sparked the AIDS Epidemic and How the World Can Finally Overcome It.

The History Of HIV

Timberg tells Fresh Air's Dave Davies that the simian version of HIV — which is called SIV — has been around for thousands of years. It was only when colonial powers migrated across parts of Africa — where the SIV virus existed among the chimps — that the virus started to spread among humans.

"It was only with the introduction of these new transport routes, of these human movements, that HIV popped out of the chimpanzee population and starts an epidemic among the human population and became what we see today," he says.

In the past 100 years, 99 percent of all of the world's deaths from AIDS have come from a strain of the virus called HIV-1 group M, which first appeared in remote parts of Cameroon, where African porters worked a century ago cutting paths across dense brush in places where humans had never before traveled.

"The best theory is that a human caught a chimp, was butchering a chimp — which is a very bloody business — and in the process of that cut his hand, and the virus mutated as it went into the human bloodstream," says Timberg. "... [There was] human movement in areas where humans didn't live in great density before colonialism arrived — you had the arrival of the rubber trade and the ivory trade, and suddenly you had to go into these very deep parts of the forest that were not hospitable to humans before and since."

From Cameroon, strains of HIV migrated down into other parts of central Africa and then into Leopoldville, which is now called Kinshasa. Leopoldville was a Belgian territory and by 1920 had become the capital of the Belgian Congo — complete with factories, shipyards, railways and single-sex dormitories for the workers, who were thrust into urban living conditions.

"You had the kind of human movement that could really get an epidemic moving," says Timberg.

In 1960, the Belgians gave up Congo, which then became an independent country again. At that point, 1,000 to 2,000 people likely had HIV, says Timberg.

"But you have to bear in mind, when HIV progresses into AIDS, it looks like a lot of other diseases," he says. "You have diarrhea, you have fevers, you have wasting. So there's not much evidence that anybody at the time had any evidence that there was a new sickness."

The unknowingly infected inhabitants of Kinshasa mingled with U.N. aid workers who were flown over from Haiti to work as physicians and civil servants. It is almost certainly the case, says Timberg, that one of the Haitian aid workers caught HIV in Leopoldville and then flew back to Haiti.

Fighting AIDS In Africa

In the 1980s in the United States, there was a large resistance to the idea that HIV and AIDS could spread widely among a heterosexual population — in part, says Timberg, because it didn't happen in many places. But across Africa, he says, it was a different story.

"The first researchers who began to look into the HIV epidemic in Africa found these unbelievable rates of infection that frankly horrified them and terrified them," he says. "When they began to write their papers about this, the peer-reviewed medical journals were like, 'You're crazy. You can't have HIV spreading like this.' But in Africa, it did."

Many African countries initially ignored the AIDS crisis, but some nations — like Uganda and Zimbabwe — were successful in providing public health information and slowing the spread of the disease. Timberg says when Western countries later became serious about fighting the African AIDS epidemic, international AIDS groups didn't follow Uganda's model — and overlooked some relatively simple and inexpensive approaches proven to stem the spread of HIV.

One of their errors, he says, was overlooking the effectiveness of male circumcision. Circumcised men are at a much lower risk of becoming infected with HIV through sexual transmission.

"When you look at the parts of not just Africa but the world where HIV is worse, it is almost inevitably societies that don't circumcise," he says. "The science on this began emerging in the 1980s and it became terribly politicized. People were uncomfortable with the subject, and the whole discussion became incredibly controversial. It took almost 20 years for the scientific community and the community of policymakers to really do enough science and enough research to realize how important this was."

Read the Rest.


[If an item is not written by an IRMA member, it should not be construed that IRMA has taken a position on the article's content, whether in support or in opposition.]

Thursday, October 13, 2011

Phylodynamics of HIV-1 Subtype B among the MSM Population in Hong Kong

via pubmed.gov, by Jonathan Hon-Kwan Chen, Ka-Hing Wong, Kenny Chi-Wai Chan, Sabrina Wai-Chi To, Zhiwei Chen, and Wing-Cheong Yam

Abstract

The men-having-sex-with-men (MSM) population has become one of the major risk groups for HIV-1 infection in the Asia Pacific countries. Hong Kong is located in the centre of Asia and the transmission history of HIV-1 subtype B transmission among MSM remained unclear. The aim of this study was to investigate the transmission dynamics of HIV-1 subtype B virus in the Hong Kong MSM population. Samples of 125 HIV-1 subtype B infected MSM patients were recruited in this study. Through this study, the subtype B epidemic in the Hong Kong MSM population was identified spreading mainly among local Chinese who caught infection locally. On the other hand, HIV-1 subtype B infected Caucasian MSM caught infection mainly outside Hong Kong. The Bayesian phylogenetic analysis also indicated that 3 separate subtype B epidemics with divergence dates in the 1990s had occurred. The first and latest epidemics were comparatively small-scaled; spreading among the local Chinese MSM while sauna-visiting was found to be the major sex partner sourcing reservoir for the first subtype B epidemic. However, the second epidemic was spread in a large-scale among local Chinese MSM with a number of them having sourced their sex partners through the internet. The epidemic virus was estimated to have a divergence date in 1987 and the infected population in Hong Kong had a logistic growth throughout the past 20 years. Our study elucidated the evolutionary and demographic history of HIV-1 subtype B virus in Hong Kong MSM population. The understanding of transmission and growth model of the subtype B epidemic provides more information on the HIV-1 transmission among MSM population in other Asia Pacific high-income countries.

Read the rest of the study here.



[If an item is not written by an IRMA member, it should not be construed that IRMA has taken a position on the article's content, whether in support or in opposition.]

Thursday, June 10, 2010

Study in The Lancet: Antiretroviral Therapy Associated with 92% Decreased Risk of HIV Transmission among HIV-1 Discordant Couples in a Large Multinational Study

via University of Washington International Clinical Research Center, by The Lancet

"HIV-positive individuals who used antiretroviral therapy (ART) reduced the risk of transmitting HIV to their uninfected partners by 92 percent." - The Lancet Journal


During the study, 349 HIV-infected partners initiated ART at an average CD4 count of 198. Of the 103 HIV infections that occurred in these couples, there was only one HIV transmission after ART initiation. In that single event, the HIV-infected partner had started ART about three months prior to HIV infection being first detected in her partner.

Antiretroviral therapy decreases the concentration of HIV in blood plasma to very low levels, the authors explained, likely making the individual less infectious to others. Viral suppression to very low levels was achieved in 70 percent of individuals in this study, at an average of seven months after starting ART.


Wednesday, May 19, 2010

Eradication of smallpox may have set the stage for HIV pandemic, study says

via Los Angeles Times, by Thomas H. Maugh II

"While these results are very interesting and hopefully may lead to a new weapon against the HIV pandemic, they are very preliminary and it is far too soon to recommend the general use of vaccinia immunization for fighting HIV," Weinstein said in a statement. Given the great difficulties researchers have encountered in trying to develop an HIV vaccine, the ironic fact is that we may once have had a vaccine that is more effective against the virus than anything that has since been developed, and we threw it away.


Laboratory tests suggest that immunity to smallpox triggered by the vaccinia (smallpox) vaccine can inhibit the replication of the AIDS virus. Such vaccination could have kept HIV transmission partially under control in the early days of the outbreak, but withdrawal of the smallpox vaccine in the 1950s would have freed it to spread unfettered, the researchers said.

Discrimination hurts fight against HIV in homosexual men in Asia-Pacific - UN

Original posted by UN News May 18

More than 90 per cent of men having sex with men in the Asia-Pacific region, a group in which HIV prevalence has reached alarming levels, do not have access to prevention and care services due to an adverse legal and social environment, a United Nations-backed forum was told today.

Read the rest.

Wednesday, May 12, 2010

Theory Explains Why Some With HIV Survive Longer





A group of researchers in Boston announced a new theory this week that may help to explain a longstanding mystery in AIDS research: why some people with HIV survive for decades without ever developing AIDS.

About one out of every 200 people who catch HIV are considered "long-term non-progressors" or "elite controllers" because they can live for many years with the virus without developing AIDS. Even the most sensitive tests often cannot detect the virus in their bloodstream.

Read the rest.

Tuesday, April 13, 2010

Microbicides, vaccines may need to repel HIV contact at mucosa

via Aidsmap News, by Keith Alcorn

Scientists have been faced with the question of how HIV actually gets underneath epithelial cells to infect other cells that are susceptible to HIV. "It's not the cells on top," Kaushic said. "It is the immune cells underneath that have all the receptors that HIV likes to latch on to and that allow the virus to replicate and establish infection. But it has to cross the epithelial barrier first!"


"This is a significant step forward in defining where prevention strategies, such as microbicides and vaccine, need to focus. Instead of trying to stop HIV from infecting the target cells underneath the epithelium, we need to think about ways to stop the virus from attaching to epithelial cells themselves," said Charu Kaushic.



Monday, August 3, 2009

New HIV strain discovered

A new strain of the virus that causes AIDS has been discovered in a woman from the African country of Cameroon.

It differs from the three known strains of human immunodeficiency virus and appears to be closely related to a form of simian virus recently discovered in wild gorillas, researchers report in Monday's edition of the journal Nature Medicine.

The finding "highlights the continuing need to watch closely for the emergence for new HIV variants, particularly in western central Africa," said the researchers, led by Jean-Christophe Plantier of the University of Rouen, France.

The three previously known HIV strains are related to the simian virus that occurs in chimpanzees.

The most likely explanation for the new find is gorilla-to-human transmission, Plantier's team said. But they added they cannot rule out the possibility that the new strain started in chimpanzees and moved into gorillas and then humans, or moved directly from chimpanzees to both gorillas and humans.

Read the rest from cbc.ca

Read the article in Nature Medicine

Plantier J-C et al. "A new human immunodeficiency virus derived from gorillas", Nature Medicine, Published online: 2 August 2009.
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