centered image

centered image

Where Did HIV Come From?

Discussion in 'Microbiology' started by Dr.Scorpiowoman, Nov 23, 2016.

  1. Dr.Scorpiowoman

    Dr.Scorpiowoman Golden Member

    Joined:
    May 23, 2016
    Messages:
    9,028
    Likes Received:
    414
    Trophy Points:
    13,075
    Gender:
    Female
    Practicing medicine in:
    Egypt

    b63bb648d52ed4e477ce839d7a167bc7.jpg

    Everyone has heard of HIV. According to estimates by the World Health Organization and the Joint United Nations Programe on HIV/AIDS, 34 million people around the world had HIV in 2010. Globally, around 6000 people die every day from HIV related illnesses. Yet the virus itself was only identified a few decades ago. Where did it all begin? How did HIV first get into the population, triggering one of the most devastating pandemics in history? This article is going to explore some of the main theories proposed so far to give you an insight into this complex but fascinating topic.

    WHAT IS HIV?

    HIV, or human immunodeficiency virus, is the causative agent of AIDS (acquired immune deficiency syndrome). There are actually two types of HIV; HIV-1 and HIV-2. HIV-1 is the dominant virus worldwide, whereas HIV-2 is largely confined to West African countries and those with links to this area such as France and Portugal.

    HIV-2 is separated into eight groups, A-H, with group A being the most prevalent worldwide. Only groups A and B have been successfully transmitted between humans- the rest have been isolated cases with “dead end” viruses. HIV-1 is divided into 4 groups; M, N, O and P. M, which has been responsible for the majority of infections worldwide, is further divided into 9 different subtypes which dominate in different countries.

    THE HIV CONSPIRACY THEORY

    There are a few different ideas that have been put forward to explain how HIV came about. The two thrown around most, by far, are: “The government did it,” or “It was definitely people having sex with monkeys!”

    There are lots of conspiracy theories surrounding HIV; some people do not believe it causes AIDS at all, and others believe that HIV is a man-made virus.

    According to a 2005 survey of African Americans living in the US, almost 50% of the respondents believed that HIV was manufactured in a lab. Furthermore, over 25% believed that this was done by the government. A significant number also believed that it was created in order to control the population of black people/homosexuals.

    There is absolutely no evidence in support these theories and a lot of evidence to suggest they're baloney. Some of the earliest documented cases of HIV were in the late 1950s; it’s absurd to think that scientists would have had the knowledge or technology to create viruses back then. We only identified the structure of DNA in 1953. We’ve only just managed to create the first synthetic bacterial genome, let alone create a virus from scratch.

    Creating a virus would require knowledge of genetic manipulation. We simply did not have the expertise to be able to achieve something like this at that time.

    TRACING THE ORIGIN OF HIV

    There exists an overwhelming amount of evidence to suggest that HIV arose from cross-species transmission of closely related viruses that are found naturally in various primate hosts in Africa.

    By looking at the genomes of these viruses, which are collectively known as simian immunodeficiency viruses (SIV), and comparing them with those of the different types of HIV we can see that the SIVs are the closest relatives of HIV. Furthermore, geographical correlations exist between SIVs in their different hosts and HIV.

    HIV-1 and HIV-2 have different origins as they arose from independent transmission events. Closely related SIVs have been found in monkeys called sooty mangabeys in Western Africa, which is the only region that HIV-2 is endemic in. Therefore, scientists conclude that HIV-2 has its origins in SIV infected sooty mangabeys.

    HIV-1 is a little more complicated, but each different group (M, N, O and P) arose from a single transmission event. M and N have been traced back to SIV infected chimpanzees (Pan troglodytes troglodytes), but the closest relatives of O and P have been found in gorillas.

    8b00dda9d6122e772132ca0e5f7b03d0.jpg



    WHEN DID HIV ENTER THE POPULATION?

    By looking at the genome sequences of different viruses over time, researchers can calibrate a “molecular clock” based on the rate of sequence change, or mutations. Scientists can then use this to infer the rate of evolution and thus determine approximately when the most recent common ancestor existed.

    Using this technique, researchers estimated that HIV-1 group M originated in 1908 and group O in 1920. HIV-2 groups A and B originated a bit later; approximately in 1940 and 1945, respectively.

    WE KNOW WHEN, WHAT ABOUT HOW?

    There are a few different theories about how these viruses got into the population. The idea that humans copulated with primates and subsequently became infected tickles the fancy of some, but this idea is not taken seriously by experts in the field! (A gorilla? Really?!)

    The simplest explanation is that humans came into contact with the blood or other secretions of infected primates which is perfectly plausible since, for example, sooty mangabeys were both kept as pets and slaughtered for bushmeat in West Africa, the same region that HIV-2 is most prevalent. It would be easy for infected bodily fluids to come into contact with broken skin during the butchering process.

    Given the fact that medical resources are costly, it is plausible that during immunization programs in Africa, healthcare professionals would have shared needles, providing ample opportunity to spread infection through the population. This, coupled with an increase in international travel alongside sexual promiscuity and intravenous drug use, seems a logical explanation for the emergence of HIV.

    Another theory is that humans became infected from contaminated oral polio vaccines. The vaccine in question was called CHAT which required the use of living tissue for production. The idea was that the kidney cells used in the production line came from SIV infected chimps and thus a large number of people were exposed. However, this theory falls down because as we have seen, not all of the HIVs came from chimps. It’s also extremely unlikely that oral vaccines would result in transmission since, unless compromised, the mouth is a pretty good barrier to infection. Furthermore, researchers found stocks of the vaccine used and when it was tested, no traces of SIV were found. This theory has therefore largely been refuted.

    58361fec7e346f67ba1c06d1d4b05bcb.jpg

    In sum, while it is difficult to definitively prove where HIV came from, we can make assertions based on the best available evidence. This evidence points to a simian (monkey or ape) origin, not the government. Everyone loves to hear about a good conspiracy theory, but it really does not add up here.

    Another theory is about: The Surgeon Who Gave Old Men Monkey Balls

    Serge Abrahamovitch Voronoff was quite the crazy character. A Russian surgeon who trained with a Nobel Prize–winning doctor, he studied the effects of castration on eunuchs while working for the king of Egypt until 1910. Obsessed with testicles, Voronoff believed the glands played a key part in the aging process. When he returned to Paris, he began offering “monkey gland operations” to aging gentlemen who wanted to regain their mental prowess and sexual potency. The first step of a monkey gland operation involves getting your hands on monkey balls. Voronoff often used baboons and chimpanzees (which are technically apes), and the process was quite intense. The primates were anesthetized and placed inside a special box that kept the animals restrained while the doctors snipped away. You don’t want an angry male chimp to wake up while you’re trying to steal the family jewels. Next, Voronoff sliced the testes into thin layers and grafted them onto the private parts of the gentleman lying on the operating table. As bizarre as it sounds, the operations were wildly popular, and by the time he retired in the 1930s, thousands of men had signed up for the procedure. The Russian earned quite a bit of cash. He moved into one of the swankiest hotels in Paris and even set up a facility specifically for breeding future “donors.” But as time went on, scientists realized that Voronoff was a major quack. Monkey gland operations were useless and didn’t actually do anything. In fact, some theorize the surgeries helped transmit AIDS from monkeys to humans though others dispute that claim. Either way, it’s safe to say that Voronoff’s operations were totally nuts.

    Source 1
    Source 2
     

    Add Reply

Share This Page

<