Origin And Epidemic Emergence
Several of the theories of HIV origin accept the established knowledge of the HIV/SIV phylogenetic relationships, and also accept that bushmeat practice was the most likely cause of the initial transfer to humans. All of them propose that the simultaneous epidemic emergences of four HIV groups in the late 19th-early 20th century, and the lack of previous known emergences, are explained by new factor that appeared in the relevant African regions in that timeframe. These new factor would have acted either to increase human exposures to SIV, to help it to adapt to the human organism by mutation , or to cause an initial burst of transmissions crossing an epidemiological threshold, and therefore increasing the probability of continued spread.
Genetic studies of the virus suggested in 2008 that the most recent common ancestor of the HIV-1 M group dates back to the Belgian Congo city of Léopoldville , circa 1910. Proponents of this dating link the HIV epidemic with the emergence of colonialism and growth of large colonial African cities, leading to social changes, including a higher degree of non-monogamous sexual activity, the spread of prostitution, and the concomitant high frequency of genital ulcer diseases in nascent colonial cities.
Social changes and urbanization
Colonialism in Africa
Impact On Gay And Bisexual Men
- While estimates show that gay and bisexual men comprise only about 2% of the U.S. population, male-to-male sexual contact accounts for most new HIV infections and most people living with HIV .58
- Annual new infections among gay and bisexual men declined overall between 2015 and 2019 but remained stable among Black and Latino gay and bisexual men.59
- Blacks gay and bisexual men accounted for the largest number of new diagnoses among this group in 2019, followed by Latino gay and bisexual men .60 Additionally, according to a recent study, Black gay and bisexual men were found to be at a much higher risk of being diagnosed with HIV during their lifetimes compared with Latino and white gay and bisexual men.61 Young Black gay and bisexual men are at particular risk â Black gay and bisexual men ages 20-29 accounted for 51% of new diagnoses among that age group and 13% of all diagnoses.62
Unresolved Questions About Hiv Origins And Emergence
The discovery of the main HIV / SIV phylogenetic relationships permits explaining broad HIV biogeography: the early centres of the HIV-1 groups were in Central Africa, where the primate reservoirs of the related SIVcpz and SIVgor viruses exist similarly, the HIV-2 groups had their centres in West Africa, where sooty mangabeys, which harbour the related SIVsmm virus, exist. However, these relationships do not explain more detailed patterns of biogeography, such as why epidemic HIV-2 groups only evolved in the Ivory Coast, which is one of only six countries harbouring the sooty mangabey. It is also unclear why the SIVcpz endemic in the chimpanzee subspecies Pan troglodytes schweinfurthii did not spawn an epidemic HIV-1 strain to humans, while the Democratic Republic of Congo was the main centre of HIV-1 group M, a virus descended from SIVcpz strains of a subspecies that does not exist in this country. It is clear that the several HIV-1 and HIV-2 strains descend from SIVcpz, SIVgor, and SIVsmm viruses, and that bushmeat practice provides the most plausible cause of cross-species transfer to humans. However, some loose ends remain.
It is not yet explained why only four HIV groups spread considerably in human populations, despite bushmeat practices being widespread in Central and West Africa, and the resulting human SIV infections being common.
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How Did Hiv Cross From Chimps To Humans
The most commonly accepted theory is that of the ‘hunter’. In this scenario, SIVcpz was transferred to humans as a result of chimps being killed and eaten, or their blood getting into cuts or wounds on people in the course of hunting.5 Normally, the hunter’s body would have fought off SIV, but on a few occasions the virus adapted itself within its new human host and became HIV-1.
There are four main groups of HIV strains , each with a slightly different genetic make-up. This supports the hunter theory because every time SIV passed from a chimpanzee to a human, it would have developed in a slightly different way within the human body, and produced a slightly different strain. This explains why there is more than one strain of HIV-1.6
The most studied strain of HIV is HIV-1 Group M, which is the strain that has spread throughout the world and is responsible for the vast majority of HIV infections today.
So Scientists Have Estimated When And Where The Most Deadly Type Of Hiv Started Infecting Humans
Most AIDS researchers believe that the “bushmeat trade” allowed the HIV-1 virus, and separately HIV-2, to enter the human bloodstream several times. Hunters who kill and butcher chimps and monkeys are regularly exposed to animal blood teeming with SIVs. If the hunters have cuts, bites, or scratches — and given the nature of their work they almost always do — they can catch the viruses from their prey. Hunters going after chimps in Cameroon could have caught the first strains of HIV-1. Sooty mangabeys, hunted and kept as pets in West Africa, could have transmitted HIV-2 to humans.
Africans have hunted chimps and monkeys and kept them as pets for centuries they’ve presumably been exposed to SIVs during most of that time. But the conditions needed for HIV to spread widely weren’t in place until after the continent was colonized and urbanized. The first victims would have found it easier to unwittingly spread the virus to sexual partners far and wide as roads and vehicles started connecting previously isolated villages and cities. Hospitals may have played a role, too. Strapped for cash, some of them probably re-used dirty needles, unknowingly infecting patients in the process.
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The Development Of Research Treatment And Prevention
Azidothymidine, also known as zidovudine, was introduced in 1987 as the first treatment for HIV. Scientists also developed treatments to reduce mother to child transmission.
In 1997, highly active antiretroviral therapy became the new treatment standard. It caused a 47 percent decline in death rates.
The Food and Drug Administration approved the first rapid HIV diagnostic test kit in November 2002. The test kit allowed hospitals to provide results with 99.6 percent accuracy in 20 minutes.
Also in 2003, the CDC reported that 40,000 new transmissions occurred each year. More than half of those transmissions came from people who didnt know they had contracted the virus. It was later discovered the number was closer to 56,300 people living with HIV. This number remains roughly the same since the late 1990s.
The World Health Organization set a goal to bring treatment to 3 million people by 2005. By 2010, about 5.25 million people had treatment, and 1.2 million people would start treatment.
Prevention: The Best Strategy
Even before CDC was designated in 1986 as the lead federal agency to inform and educate Americans about AIDS, the agency worked with uncommon flexibility with state and local public health agencies and community-based organizations to reach people most at risk. Science-based guidelines were translated into messages for target groups about how to make healthy choices, and how to prevent the spread of the disease. Other campaigns were designed to fight against stigma and fear by informing people about the nature of the disease, teaching tolerance and compassion for those who were HIV positive.
Displayed here are a set of slides from the HIV/AIDS Library and Narrative used by the Wisconsin Department of Health and Human Services in 1989 to train community-based AIDS service organizations. Furthermore, since testing became available in 1985, CDC began providing federal funds to establish an extensive system of alternate testing and counseling sites, leading to the first nationwide HIV- and AIDS-related prevention program. Today, testingknowing ones HIV statusis a key strategy in AIDS prevention.
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A Timeline Of Hiv And Aids
The HIV.gov Timeline reflects the history of the domestic HIV/AIDS epidemic from the first reported cases in 1981 to the presentwhere advances in HIV prevention, care, and treatment offer hope for a long, healthy life to people who are living with, or at risk for, HIV and AIDS.
View a timeline of the current Ending the HIV Epidemic initiative. Please visit HIVHistory.org for a timeline of the global and domestic response to the HIV epidemic.
The History Of Aids In Africa
It all started as a rumour Then we found we were dealing with a disease. Then we realised that it was an epidemic. And, now we have accepted it as a tragedy. – Chief epidemiologist in Kampala, Uganda
There is now conclusive evidence that HIV originated in Africa. A 10-year study completed in 2005 found a strain of Simian Immunodeficiency Virus in a number of chimpanzee colonies in south-east Cameroon that was a viral ancestor of the HIV-1 that causes AIDS in humans.
A complex computer model of the evolution of HIV-1 has suggested that the first transfer of SIV to humans occurred around 1930, with HIV-2 transferring from monkeys found in Guinea-Bissau, at some point in the 1940s .
Studies of primates in other continents did not find any trace of SIV, leading to the conclusion that HIV originated in Africa.
The 1960s- Early cases of AIDSExperts studying the spread of the epidemic suggest that about 2,000 people in Africa may have been infected with HIV by the 1960s. Stored blood samples from an American malaria research project carried out in the Congo in 1959 prove one such example of early HIV infection.The 1970s The first AIDS epidemicIt was in Kinshasa in the 1970s that the first epidemic of HIV/AIDS is believed to have occurred. The emerging epidemic in the Congolese capital was signalled by a surge in opportunistic infections, such as cryptococcal meningitis, Kaposis sarcoma, tuberculosis and specific forms of pneumonia.
Confusion, stigma and despondence
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What Happened In The 1980s In The Usa
People sometimes say that HIV started in the 1980s in the United States of America , but in fact this was just when people first became aware of HIV and it was officially recognised as a new health condition.
In 1981, a few cases of rare diseases were being reported among gay men in New York and California, such as Kaposi’s Sarcoma and a lung infection called PCP.1516 No one knew why these cancers and opportunistic infections were spreading, but they concluded that there must be an infectious ‘disease’ causing them.
At first the disease was called all sorts of names relating to the word ‘gay’.17 It wasn’t until mid-1982 that scientists realised the ‘disease’ was also spreading among other populations such as haemophiliacs and heroin users.1819 By September that year, the ‘disease’ was finally named AIDS.20
It was only in 1983 that the HIV virus was isolated and identified by researchers at the Pasteur Institute in France. Originally called Lymphadenopathy-Associated Virus the virus was confirmed as the cause of AIDS, when scientists working at the USA National Cancer Institute isolated the same virus and called it HTLV-III. LAV and HTLV-III were later acknowledged to be the same.
The Patient Zero Myth
For decades, a French-Canadian airline employee named Gaetan Dugas, has been known as Patient Zero in the 1980s AIDS epidemic.
Dugas, a man who had sex with men , died in 1984. Since then he has been blamed by some as a primary source for the spread of HIV in North America.
Dugas was one of the primary villains in the 1987 book, And the Band Played On, by San Francisco journalist Randy Shilts.
However, the researchers now say Dugas was falsely accused and unfairly blamed.
Gaetan Dugas is one of the most demonized patients in history, and one of a long line of individuals and groups vilified in the belief that they somehow fueled epidemics with malicious intent, said Richard McKay, D.Phil., a Wellcome Trust Research Fellow in Cambridges Department of History and Philosophy of Science, in a press release.
In fact, McKay says, Dugas actually provided scientists with valuable information before he died.
Dugas told researchers after he contracted HIV that he had 750 sexual partners the previous three years. That wasnt necessarily an unusual number. Researchers said 65 percent of men in a Los Angeles cluster study at the time reported having more than 1,000 sexual partners in their lifetimes.
Much of that sexual connection was with anonymous partners, so many HIV patients couldnt give medical officials any names.
However, McKay says, Dugas provided medical officials with 72 names. That helped scientists track down a wide range of people infected with HIV.
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When And Where Did Hiv Start In Humans
Studies of some of the earliest known samples of HIV provide clues about when it first appeared in humans and how it evolved. The first verified case of HIV is from a blood sample taken in 1959 from a man living in what is now Kinshasa in the Democratic Republic of Congo. The sample was retrospectively analysed and HIV detected. There are numerous earlier cases where patterns of deaths from common opportunistic infections, now known to be AIDS-defining, suggest that HIV was the cause, but this is the earliest incident where a blood sample can verify infection.9
Impact On Communities Of Color
- Racial and ethnic minorities have been disproportionately affected by HIV/AIDS since the beginning of the epidemic, and represent the majority of new HIV diagnoses, people living with HIV disease, and deaths among people with HIV.37,38
- Black and Latino people account for a disproportionate share of new HIV diagnoses, relative to their size in the U.S. population .39,40 Black people also account for more people living with HIV than any other racial group â an estimated 479,300 of the 1.2 million people living with HIV in the U.S. are black.41
- Black people also have the highest rate of new HIV diagnoses, followed by Latino people â in 2019, the rate of new HIV diagnoses per 100,000 for Black people was about 8 times that of white people Latino people had a rate 4 times that of white people.42
- Black people accounted for close to half of deaths among people with an HIV diagnosis in 2019.43,44
- Survival after an AIDS diagnosis is lower for Black people than for most other racial/ethnic groups, and Black people have had the highest age-adjusted death rate due to HIV disease throughout most of the epidemic.45 HIV ranks higher as a cause of death for Black and Latino people, compared with White people.46 Further, HIV was the 6th leading cause of death for Black people ages 25-34 in 2019.47
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Scientists Refute Theory About The Origin Of Hiv
The HIV virus, and the epidemic of AIDS it has unleashed in the world in the last two decades, has prompted a strenuous scientific effort at stopping the organism and treating the devastating disease that results. But it has also been the source of speculation about the history of the virus itself: Where did it come from? How did it come to reside in humans? And what happened to transform it from a relative innocuous organism into a worldwide killer?
The spectacular nature of the epidemic has prompted some to suggest that the virus could not have naturally become so deadly without some human intervention — some tragic mistake that lifted it out of benign obscurity.
One such provocative theory has suggested that the HIV virus, originally residing in chimpanzees, was accidentally transferred to humans in the late 1950s during a polio vaccine campaign in Africa. According to the theory, first put forward by a journalist named Edward Hooper, public health workers may have used infected cells from chimpanzee kidneys to culture the polio virus when millions of people were vaccinated during the worldwide campaign to eradicate that disease — so the theory assumes — the virus began its insidious spread in the human race.
Edward C. Holmes, PhD, author of one of the reports, says the new research shows that the spread of HIV virus occurred naturally the way any organism does, and not through human error.
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.
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Where Did Hiv Come From A Look At The Origins Of The Pandemic Of Our Time
A chimpanzees virus has killed 35 million humans.
That virus, commonly known as HIV, is the defining pandemic of our time. More than 35 million people have been killed by the virus to date. But the virus itself didnt get its start in humans.
HIV/AIDS is, like the vast majority of emerging viruses infecting people, zoonotic in nature. The AIDS crisis, as we generally think of it, began in the 1980s. First as a mysterious illness primarily infecting gay men in urban areas in the United States. But thats not really the beginning. Before the diseases first mention in 1982 in the New York Times, people had been dying of AIDS for at least a decade, though probably not much longer. In Africa, HIVthe virus that causes AIDShad jumped from chimpanzees to humans sometime early in the 20th century.
To date, the earliest known case of HIV-1 infection in human blood is from a sample taken in 1959 from a man whod died in Kinshasa in what was then the Belgian Congo.
Its this fact which keeps me awake at night. Imagine, for a moment, that the HIV virus in that 1959 sample had been studied and identified. If, in the 1950s, the scientific community realized the potential harm this new virus could unleash. What could we have done? What therapies could we have developed before it became one of the deadliest pandemics in human history? Would we have a cure by now?
That work takes several forms, including: