HIV and its origins

The BBC has an article by James Gallagher about HIV and another by him about the original of it:

HIV is evolving to become less deadly and less infectious, according to a major scientific study. The team at the University of Oxford said the virus is being "watered down" as it adapts to our immune systems. It said it was taking longer for HIV infection to cause AIDS, and that the changes in the virus may help efforts to contain the pandemic. Some virologists suggest the virus may eventually become "almost harmless" as it continues to evolve.
More than thirty-five million people around the world are infected with HIV and, inside their bodies, a devastating battle takes place between the immune system and the virus.
HIV is a master of disguise. It rapidly and effortlessly mutates to evade and adapt to the immune system. However, every so often, HIV infects someone with a particularly effective immune system. "Then the virus is trapped between a rock and hard place. It can get flattened, or make a change to survive and, if it has to change, then that will come with a cost," said Professor Philip Goulder of the University of Oxford. The "cost" is a reduced ability to replicate, which in turn makes the virus less infectious and means it takes longer to cause AIDS.
Professor Dausey of Mercyhurst University said: "We have to be cautiously optimistic about this study"
This weakened virus is then spread to other people and a slow cycle of "watering-down" HIV begins. The team showed this process happening in Africa by comparing Botswana, which has had an HIV problem for a long time, and South Africa, where HIV arrived a decade later.
Professor Goulder told the BBC News website: "It is quite striking. You can see the ability to replicate is ten percent lower in Botswana than South Africa, and that's quite exciting. We are observing evolution happening in front of us, and it is surprising how quickly the process is happening. The virus is slowing down in its ability to cause disease and that will help contribute to elimination."The findings, in the Proceedings of the National Academy of Sciences, also suggested anti-retroviral drugs were forcing HIV to evolve into milder forms. It showed the drugs would primarily target the nastiest versions of HIV and encourage the milder ones to thrive.
Professor Goulder added: "Twenty years ago the time to AIDS was ten years, but, in the last ten years in Botswana, that might have increased to more than twelve years, a sort of incremental change, but in the big picture that is a rapid change. One might imagine, as time extends, this could stretch further and further and, in the future, people being asymptomatic for decades."
The group did caution that even a watered-down version of HIV was still dangerous and could cause AIDS.
Chimpanzee
HIV originally came from apes or monkeys, in which it is frequently a minor infection.
Professor Jonathan Ball, a virologist at the University of Nottingham, told the BBC that: "If the trend continues then we might see the global picture change, a longer disease causing much less transmission. In theory, if we were to let HIV run its course, then we would see a human population emerge that was more resistant to the virus than we collectively are today, and HIV infection would eventually become almost harmless. Such events have probably happened throughout history, but we are talking very large timescales."
Professor Andrew Freedman, a reader in infectious diseases at Cardiff University in Wales, said this was an "intriguing study. By comparing the epidemic in Botswana with that which occurred somewhat later in South Africa, the researchers were able to demonstrate that the effect of this evolution is for the virus to become less virulent, or weaker, over time. The widespread use of antiretroviral therapy may also have a similar effect and together, these effects may contribute to the ultimate control of the HIV epidemic." But he cautioned that HIV was "an awfully long way" from becoming harmless and "other events will supersede that, including wider access to treatment and eventually the development of a cure".

Rico says it'd be nice if HIV (along with Ebola) evolved away...

The origin of the AIDS pandemic has been traced to the 1920s in the city of Kinshasa, in what is now the Democratic Republic of the Congo, scientists say.
An international team of scientists say a "perfect storm" of population growth, sex and railways allowed HIV to spread.
A feat of viral archaeology was used to find the pandemic's origin, the team has reported in the journal Science. They used archived samples of HIV's genetic code to trace its source, with evidence pointing to 1920s Kinshasa.
Their report says a roaring sex trade, rapid population growth, and unsterilised needles used in health clinics probably spread the virus. Meanwhile Belgian-backed railways had one million people flowing through the city each year, taking the virus to neighboring regions. Experts said it is a fascinating insight into the start of the pandemic.
HIV came to global attention in the 1980s and has infected nearly seventy-five million people. It has a much longer history in Africa, but where the pandemic started has remained the source of considerable debate.
A team at the University of Oxford in England and the University of Leuven in Belgium, tried to reconstruct HIV's "family tree" and find out where its oldest ancestors came from The research group analyzed mutations in HIV's genetic code. "You can see the footprints of history in today's genomes, it has left a record, a mutation mark in the HIV genome that can't be eradicated," Professor Oliver Pybus from the University of Oxford told the BBC. By reading those mutational marks, the research team rebuilt the family tree and traced its roots.
HIV is a mutated version of a chimpanzee virus, known as simian immunodeficiency virus, which probably made the species-jump through contact with infected blood while handling bush meat. The virus made the jump on multiple occasions. One event led to HIV-1 subgroup O, which affects tens of thousands in Cameroon. Yet only one cross-species jump, HIV-1 subgroup M, went on to infect millions of people across every country in the world. The answer to why this happened lies in the era of black and white film and the tail-end of the European empires.
In the 1920s, Kinshasa (called Leopoldville until 1966) was part of the Belgian Congo.
Professor Oliver Pybus said that: "It was a very large and very rapidly growing area and colonial medical records show there was a high incidence of various sexually transmitted diseases." Large numbers of male laborers were drawn to the city, distorting the gender balance until men outnumbered women two to one, eventually leading to a roaring sex trade.
Professor Pybus added: "There are two aspects of infrastructure that could have helped.
"Public health campaigns to treat people for various infectious diseases with injections seem a plausible route for spreading the virus. The second really interesting aspect is the transport networks that enabled people to move round a huge country."
Around one million people were using Kinshasa's railways by the end of the 1940s.
The virus spread, with neighboring Brazzaville and the mining province, Katanga, rapidly hit. Those "perfect storm" conditions lasted just a few decades in Kinshasa but, by the time they ended, the virus was already starting to spread around the world.
Professor Jonathan Ball, from the University of Nottingham, told the BBC: "It's a fascinating insight into the early phases of the HIV-1 pandemic. It's the usual suspects that are most likely to have helped the virus get a foothold in humans: travel, population increases, and human practices such as unsafe healthcare interventions and prostitution. Perhaps the most contentious suggestion is that the spread of the M-group viruses had more to do with the conditions being right than it had to do with these viruses being better adapted for transmission and growth in humans. I'm sure this suggestion will prompt interesting and lively debate within the field."
Dr. Andrew Freedman, a reader in infectious diseases at Cardiff University in Wales, said: "It does seem an interesting study, demonstrating very elegantly how HIV spread in the Congo region long before the AIDS epidemic was recognized in the early 1980s. It was already known that HIV in humans arose by cross-species transmission from chimpanzees in that region of Africa, but this study maps in great detail the spread of the virus from Kinshasa."