If there is no risk while having sex or sharing needles with a person who is not infected. How did HIV come to exist? You have to have an infected person to transmit the disease. How did the first person to get HIV get it?
Hi. Thank you for your question.
As best as we can tell, the HIV virus evolved from the SIV (monkey AIDS virus). This is thought to be true because there is a high degree of genetic similarity between these 2 viruses, and because they are both transmitted in the same manner, and both cause the same disease. The only difference is that HIV only causes AIDS in humans, and SIV only causes AIDS in monkeys.
As man encroaches more and more in the forests in the world, we are being exposed to diseases that we have never been exposed to before. The Ebola Virus in Africa is a great example of this.
The following is the best hypothesis as to how HIV began. It is now thought that a strain of the SIV virus, through natural evolution, evolved into HIV. It is thought that persons in Africa (where AIDS first began) were exposed to HIV by exposure to monkey blood. Once HIV got into the human population, it spread over time primarily through heterosexual contact (which is still the case today). As the years progressed, it began to spread around the world. With people flying around the world in airplanes, diseases now spread around the world in a matter of hours, rather than years or decades (before airplanes were developed).
New diseases among humans do occur from time to time. Just in the past 20 years, besides AIDS, we have now seen Legionaires Disease, Toxic Shock Syndrome, Chronic Fatigue Syndrome, and Ebola Virus. New diseases will always be seen from time to time. Diseases are an ongoing part of nature.
All the evidence goes against HIV being a man-made virus. This virus was first thought to have begun in the late 1950's to early 1960's in Africa. During these years, we did not have the technology to study viruses, let alone create viruses. The tools to study viruses have primarily been developed in the 1970's, 1980's, and 1990's. Our technological capabilities to study viruses are still crude today. We simply did not have the technological capabilities to make a virus during the 1950's and 1960's. And even today, we can alter viruses (to a limited extent), but we still cannot invent totally new viruses.
So in summary, HIV is now believed to have naturally evolved from SIV in Africa in the late 1950's to early 1960's. When humans got exposed to infected monkey blood, the virus then spread throughout the human population through sexual contact. Over time this became a worldwide disease.
If you have any further questions, please feel free to call the Centers for Disease Control at 1.800.232.4636 (Nationwide). Rick Sowadsky MSPH CDS