Hello Manoa Explorers!
Today, we're diving deep into the history of HIV and AIDS, to understand the origins and progression of these life-altering diseases that have affected millions across the globe. It's important to reflect on this history, as it allows us to appreciate the progress made and renews our determination to fight for a future without HIV/AIDS, or at least zero AIDS-related deaths.
The Discovery of HIV/AIDS
It all began in the early 1980s when medical professionals in the United States noticed a peculiar pattern of rare illnesses among young, previously healthy homosexual men. These illnesses included a rare type of pneumonia and a skin cancer known as Kaposi's sarcoma. As cases increased, it became clear that something sinister was at work – a new, unknown virus was causing the weakening of the immune system. A few years later, in 1983, French virologist Dr. Luc Montagnier and his team at the Pasteur Institute discovered the virus, which they called Lymphadenopathy-Associated Virus (LAV). The following year, American researcher Dr. Robert Gallo and his team also discovered the virus and named it Human T-Cell Lymphotropic Virus (HTLV-III). Eventually, the virus was named Human Immunodeficiency Virus (HIV), and the condition caused by it, Acquired Immunodeficiency Syndrome (AIDS). It is very important to know what the difference is between HIV and AIDS.
Origins of HIV
HIV is believed to have originated from a type of chimpanzee in Central Africa. Researchers think that when humans hunted these animals for food, they came into contact with their infected blood, leading to the transmission of the virus to humans. This cross-species transmission likely occurred in the early 20th century.
HIV is classified into two types: HIV-1 and HIV-2. HIV-1 is more prevalent and aggressive, while HIV-2 is primarily found in West Africa. Both types are believed to have originated from Simian Immunodeficiency Viruses (SIVs) found in different species of primates.
Understanding the diverse ways SIV affects non-human primates can provide valuable insights into the mechanisms of HIV pathogenesis in humans
Simian Immunodeficiency Virus (SIV) infects non-human primates, including chimpanzees, gorillas, sooty mangabeys, and several other species of African monkeys. Although SIV is closely related to HIV and shares many similarities, its impact on non-human primates varies depending on the species.
In some cases, SIV infection in non-human primates resembles HIV infection in humans, leading to a weakened immune system and an increased susceptibility to opportunistic infections. For example, SIVcpz, which infects chimpanzees, has been associated with a higher risk of morbidity and mortality in the infected animals. Research has shown that SIVcpz-infected chimpanzees can develop a disease similar to AIDS in humans, with a decline in CD4+ T-cells and increased susceptibility to infections.
However, in other species of non-human primates, SIV infection appears to be non-pathogenic or causes only mild symptoms. Sooty mangabeys (a type of monkey if you don’t happen to be a monkey expert…), which are the natural host for SIVsmm (the precursor of HIV-2), usually do not develop severe immunodeficiency or AIDS-like symptoms when infected with the virus. Their immune systems have evolved to coexist with the virus without significant health consequences. Similarly, African green monkeys infected with their species-specific SIV strain typically do not show signs of disease.
The differences in the impact of SIV infection among non-human primates can be attributed to several factors, including the co-evolution of the virus and its host, as well as differences in the host immune response. In species where SIV infection is non-pathogenic, the host immune system appears to have adapted to the virus, minimizing the inflammatory response that often contributes to the progression of immunodeficiency in humans with HIV.
Understanding the diverse ways SIV affects non-human primates can provide valuable insights into the mechanisms of HIV pathogenesis (the process by which an infection leads to a disease) in humans and inform the development of novel treatment strategies and vaccines.
HIV-1 Origins
HIV-1 is the more prevalent and virulent form of the virus. It is responsible for the global HIV/AIDS pandemic. HIV-1 is closely related to a strain of SIV found in chimpanzees called SIVcpz (could this help us find a treatment in the future? We hope so!). It is believed that the transmission of SIVcpz from chimpanzees to humans gave rise to HIV-1.
The transmission likely occurred when humans hunted chimpanzees for bushmeat in Central Africa, coming into contact with the infected blood of the animals. This initial cross-species transmission, or zoonosis (COVID being another example of cross-species transmission), is estimated to have happened in the early 20th century. HIV-1 has several subtypes (group M, N, O, and P), with group M being the most widespread and responsible for the majority of HIV infections globally.
HIV-2 Origins
HIV-2 is primarily found in West Africa and is less virulent than HIV-1. It shares a closer genetic similarity to SIVsmm, a strain of Simian Immunodeficiency Virus found in sooty mangabeys. Like HIV-1, it is believed that HIV-2 arose from the transmission of SIVsmm to humans when they hunted sooty mangabeys for bushmeat.
HIV-2 was first identified in 1986, and although it can lead to AIDS, the progression to the disease tends to be slower than with HIV-1. Additionally, people infected with HIV-2 are less likely to transmit the virus to others.
HIV virus's ability to mutate rapidly and attack the immune system has made vaccine development a significant challenge
The Global HIV/AIDS Pandemic
From the 1980s onwards, HIV/AIDS spread rapidly across the globe, affecting millions. Sub-Saharan Africa was hit hardest, with the disease becoming the leading cause of death in the region by the early 2000s. Nowadays more than 38 million people live with HIV around the world (and it all started with a monkey...). Stigma, discrimination, and misinformation further exacerbated the problem, making it challenging to address the issue effectively.
However, the global community mobilized to combat the epidemic. In 1987, the first antiretroviral drug, AZT, was approved for the treatment of HIV. Over the years, researchers have developed more effective antiretroviral therapies (ART), which have saved millions of lives and allowed people living with HIV to lead healthier lives.
The Road to a Vaccine
For decades, scientists have been searching for an effective HIV vaccine. Although several candidates have entered clinical trials, none have yet provided adequate protection against the virus. The HIV virus's ability to mutate rapidly and attack the immune system has made vaccine development a significant challenge. Despite these hurdles, research continues, and scientists remain optimistic about eventually finding a successful vaccine.
The history of HIV/AIDS is a somber reminder of the devastating impact diseases can have on humanity. However, it also showcases our ability to come together, share knowledge, and work towards a common goal. As we continue to make strides in understanding and treating HIV/AIDS, let us not forget that we are closer than ever to reaching international goals. This is where MANOA comes in, thanks to your help, as we raise awareness and search for innovative ways to make a difference to take us closer to an HIV-free world.
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