Quote:
Originally Posted by jrafe
What about this?
http://www.africa.upenn.edu/Urgent_A..._Contract.html
"The theory of the African origin of AIDS, that it developed in African
monkeys and was transferred to man, has been abandoned by most
researchers. All of the known varieties of SIV (Simian Immunodeficiency
Virus) are structurally so dissimilar to HIV (much less similar than HIV
and Visna) that a common origin is out of the question. Furthermore,
even if such a development by natural mutation were possible, it would
not explain the sudden outbreak of AIDS in the early 1980s, since
monkeys and men have been living together in Africa since the beginning
of human history.
The "Africa Legend," as it is called in a 1988 West German
(Westdeutscher Rundfunk) television documentary, is further debunked by
the epidemiological history of AIDS. There is no solid evidence of AIDS
in Africa before 1983. The earliest documented cases of AIDS date from
1979 in New York."
There is always evidence to go either way. So do you know for sure? I sure don't. |
Here is some current data from an AIDS awareness website...
So did HIV come from an SIV?
It is now thought that HIV came from a similar virus found in chimpanzees.
It is now generally accepted that HIV is a descendant of a Simian Immunodeficiency Virus because certain strains of SIVs bear a very close resemblance to HIV-1 and HIV-2, the two types of HIV.
HIV-2 for example corresponds to SIVsm, a strain of the Simian Immunodeficiency Virus found in the sooty mangabey (also known as the green monkey), which is indigenous to western Africa.
The more virulent, pandemic strain of HIV, namely HIV-1, was until recently more difficult to place. Until 1999, the closest counterpart that had been identified was SIVcpz, the SIV found in chimpanzees. However, this virus still had certain significant differences from HIV.
What happened in 1999?
In February 1999 a group of researchers from the University of Alabama1 announced that they had found a type of SIVcpz that was almost identical to HIV-1. This particular strain was identified in a frozen sample taken from a captive member of the sub-group of chimpanzees known as Pan troglodytes troglodytes (P. t. troglodytes), which were once common in west-central Africa.
The researchers (lead by Paul Sharp of Nottingham University and Beatrice Hahn of the University of Alabama) made the discovery during the course of a 10-year long study into the origins of the virus. They claimed that this sample proved that chimpanzees were the source of HIV-1, and that the virus had at some point crossed species from chimps to humans.
Their final findings were published two years later in Nature magazine2. In this article, they concluded that wild chimps had been infected simultaneously with two different simian immunodeficiency viruses which had "viral sex" to form a third virus that could be passed on to other chimps and, more significantly, was capable of infecting humans and causing AIDS.
These two different viruses were traced back to a SIV that infected red-capped mangabeys and one found in greater spot-nosed monkeys. They believe that the hybridisation took place inside chimps that had become infected with both strains of SIV after they hunted and killed the two smaller species of monkey.
They also concluded that all three 'groups' of HIV-1 - namely Group M, N and O (see our strains and subtypes page for more information on these) - came from the SIV found in P. t. troglodytes, and that each group represented a separate crossover 'event' from chimps to humans.
How could HIV have crossed species?
It has been known for a long time that certain viruses can pass between species. Indeed, the very fact that chimpanzees obtained SIV from two other species of ape shows just how easily this crossover can occur. As animals ourselves, we are just as susceptible. When a viral transfer between animals and humans takes place, it is known as zoonosis.
Below are some of the most common theories about how this 'zoonosis' took place, and how SIV became HIV in humans:
The 'Hunter' Theory
The most commonly accepted theory is that of the 'hunter'. In this scenario, SIVcpz was transferred to humans as a result of chimps being killed and eaten or their blood getting into cuts or wounds on the hunter. Normally the hunter's body would have fought off SIV, but on a few occasions it adapted itself within its new human host and become HIV-1. The fact that there were several different early strains of HIV, each with a slightly different genetic make-up (the most common of which was HIV-1 group M), would support this theory: every time it passed from a chimpanzee to a man, it would have developed in a slightly different way within his body, and thus produced a slightly different strain.
An article published in The Lancet in 20043, also shows how retroviral transfer from primates to hunters is still occurring even today. In a sample of 1099 individuals in Cameroon , they discovered to ten (1%) were infected with SFV (Simian Foamy Virus), an illness which, like SIV, was previously thought only to infect primates. All these infections were believed to have been acquired through the butchering and consumption of monkey and ape meat. Discoveries such as this have lead to calls for an outright ban on bushmeat hunting to prevent simian viruses being passed to humans.
Other theories can be found at:
http://www.avert.org/origins.htm
conspiratory
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