The first two replies are excellent, and especially the website link gives a good overview of the contemporary theories (including some conspiracies,
already widely discussed on ATS) of the origins of HIV/AIDS.
The most likely scenario is that a primate virus (SIV) infected humans during the process of butchery (rather than a bite or beastiality)
Butchery in the African bush-meat trade is often crude, and accidents with machetes are not uncommon.
It is in this scenario that primate blood is very likely to mix into human cuts and wounds.
A 2004 study of 1 099 people involved in animal hunting and butchery in Cameroon showed that 10 had contracted simian viruses. SIV provably jumped to
humans at least 11 times (and it's considered more common than this).
(John Ilifee: The African AIDS Epidemic: A History. Ohio University Press
. Pp. 3-10.)
Other primate viruses like Monkeypox are also watched for mutations that make them infectious between humans, rather than direct zoonosis.
However a more rare mutation in some individuals caused SIV to become the infectious HIV of today.
That happened at least twice, once from chimpanzees in central Africa (giving rise to the HIV1 strain that forms the bulk of today's epidemic) and
once from the mangabey monkey in West Africa (giving rise to the less virulent and more localized strain of HIV2).
Not all the early sub-strains identified by virologists were successful, and some died out at a local level.
This could suggest that HIV was around since time immemorial, but that social and geographical factors prevented any epidemic spread.
The spread of HIV as an epidemic is therefore often connected to social changes in Africa at a specific time, including factors like war,
urbanization, migrant labor (all disruptive to families and traditional sexual patterns) and the opening of transport routes (as well as weakened
immune systems, sometimes due to famines and other STD epidemics).
The process is also continuing.
In 2009 it was reported that a strain of HIV related to gorilla SIV was found in an African woman (although it's assumed that she caught it via sexual
transmission from a man involved in the bush-meat trade).
The bush-meat trade is not always legal, and often amounts to poaching in conservation areas.
Nevertheless the market is driven by desperately poor people, who compete for dwindling natural resources.
In fact, some might see an environmental and social warning from HIV, rather than one of sexual morality.
Medical procedures and blood products can be regarded as exceptional cases of infection in Western countries these days, rather than statistical
drivers of the epidemic, so I'd say that if two people who don't inject drugs and are HIV negative form a truly monogamous relationship then they will
not contract HIV or other STDs.
Assuming that all the partners are faithful, even in a polygamous relationship they will not contract HIV.
Unfortunately, because sexual behavior is still stigmatized, people can have selective memories on their sexual history, or lie about their current
Because HIV has a long phase where infected people are asymptomatic, there is no way but the sharing of specific HIV test results for partners to know
the truth about each other, and although more couples are going for tests and counseling, many still find it uncomfortable, intimidating and
In HIV studies sex is thought of as a network, rather than just two people, and in some countries making HIV notifiable and modern tests for specific
strains can help to identify individuals who are deliberately and knowingly spreading HIV (usually just a few individuals), or to identify people who
should be advised to get tested and take the appropriate measures.
In South Africa the pandemic is still too wide for this, and especially the pattern of concurrent partnerships can make it difficult to always say
medically who infected whom.
HIV positive people can re-infect each other, giving rise to new strains that complicate treatment.
In poorer countries sex is also an economic and gender issue, and where women are dependent on men they have little choice in negotiating safer sex
with a male partner, even if they know or suspect he is philandering, and women may also engage in transactional sex for money and goods.
Men in high-risk migrant occupations (like mining in SA) may not always see a long-term risk like HIV as a priority, although attitudes are
While monogamy between two people is a great ideal and should be encouraged as such, it has also led to stigmas and denials that have slowed the
containment of HIV in some countries.
The sooner people look past nationalistic and religious discourses of what "our" people "should be doing" to patterns of "what they are actually
doing", the sooner proven public health measures can be taken.
edit on 13-9-2012 by halfoldman because: (no reason given)