Every scientific report I have read points to the origin of the HIV virus as being a mutation from Chimpanzees/Apes native to Africa that somehow crossed species lines into humans...I have never heard of any evidence that HIV/AIDS originated in the US.
Is the author confusing "first diagnoses" and "origin"?
It would make sense that the most developed medical care system would 'first diagnose' the problem...but that is a far cry from 'it originated' here.
Absolutely correct.
But there isn't any good reason to suppose that this virus recently jumped from apes to man.
All the epidemiology indicates that HIV is a very old infection in man; hundreds or thousands of years old, in fact. All evidence points to the conclusion that HIV is a benign passenger retrovirus, just like many other similar virii that have been hitchhiking in man since time immemorial.
Yes. The terminology in this field sometimes gets impenetrable very fast. What the authors are evidently referring to is the twin foci of the epidemic, not the origin of the disease. One other difference between HIV and the other viruses mentioned is that it is a "slow" virus, meaning its translation into detectable symptoms is so slow that normal epidemiological treatments of disease gradient are difficult or impossible to establish. We do know it was communicated very rapidly in those regions and that the vector was unprotected anal intercourse.
What really makes diagnosis difficult is that the patient always dies of something other than the primary effect of the disease, which is the compromise of the immune system. In fact, many non-political skeptics were difficult to convince that it even was a disease early on until it became apparent that gay men were dying of some very strange diseases in numbers never seen in medicine before - pneumocystis pneumonia, Kaposi's sarcoma, cytomegalovirus infections in various organs - weird stuff.
In Africa diagnosis is more difficult for three (at least) reasons - first, that exposure to severe disease there is more common than in New York and San Francisco, hence many of the diseases that AIDS made the patients more vulnerable to might have killed them anyway - this makes it more difficult to cite the presence of these diseases alone as evidence of AIDS. With someone turning up with something rare like Kaposi's in the States it's a pretty good bet, with someone coming up with malaria in Africa it isn't. Hence it is more necessary to test for actual HIV antibodies in Africa than in the States in order to gain accurate statistics, which is precisely what that less-developed continent cannot do due to lack of resources. That is the second reason to be skeptical about African statistics. The third reason is that money is involved and countries have an incentive for exaggerating these statistics or at least interpreting the raw numbers in the most severe possible manner. More cases, more aid. Not only could they not do better if they wanted to, they have a reason for not wanting to.