Did Hiv Start In Africa
Using the earliest known sample of HIV, scientists have been able to create a ‘family-tree’ ancestry of HIV transmission, allowing them to discover where HIV started.
Their studies concluded that the first transmission of SIV to HIV in humans took place around 1920 in Kinshasa in the Democratic Republic of Congo .10
The same area is known for having the most genetic diversity in HIV strains in the world, reflecting the number of different times SIV was passed to humans. Many of the first cases of AIDS were recorded there too.
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.
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
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Aids: Origin Of Pandemic ‘was 1920s Kinshasa’
Health editor, BBC News website
The origin of the Aids pandemic has been traced to the 1920s in the city of Kinshasa, in what is now the Democratic Republic of Congo, scientists say.
An international team of scientists say a “perfect storm” of population growth, sex and railways allowed HIV to spread.
A feat of viral archaeology was used to find the pandemic’s origin, the team report in the journal Science.
They used archived samples of HIV’s genetic code to trace its source, with evidence pointing to 1920s Kinshasa.
Their report says a roaring sex trade, rapid population growth and unsterilised needles used in health clinics probably spread the virus.
Meanwhile Belgium-backed railways had one million people flowing through the city each year, taking the virus to neighbouring regions.
Experts said it was a fascinating insight into the start of the pandemic.
HIV came to global attention in the 1980s and has infected nearly 75 million people.
It has a much longer history in Africa, but where the pandemic started has remained the source of considerable debate.
Chimp Siv Is Different
Chimpanzee SIV is an exception. Two papers published last summer point out that the SIV carried by chimpanzees appears to be a recombinant of SIVs carried by cercopithecids, upon which chimpanzees prey. As chimpanzee SIV appears to be most similar to HIV, it will aid in our understanding of the infectivity of HIV to find out how SIVcpz evolved and whether chimpanzees, which still prey on monkeys, are being reinfected. Because SIVcpz apparently is the root of HIV-1, it is essential that researchers understand where it came from.
There are four subspecies of chimpanzees: Pan troglodytes troglodytes, Pan troglodytes verus, Pan troglodytes vellerosus, and Pan troglodytes schweinfurthii. P. t. troglodytes is the subspecies present in Cameroon, Equatorial Guinea, Gabon, and Republic of the Congo. The SIV that infects this subspecies is similar to all known groups of HIV-1. A small percentage of P. t. schweinfurthii, which is endemic to the area east of the southward-flowing Ubangi River, also carries a chimpanzee SIV. That SIV, however, differs from the one that infects P. t. troglodytes and has not so far been implicated in human disease.
But, says Marx, the next question is not just how and where SIV jumped from nonhuman primates, but what makes HIV infectious and transmissible in humans. Answers to these questions may aid in determining why HIV makes humans very, very sick, while SIV causes no disease in other higher primates.
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Why Do Gay Men Have An Increased Risk Of Hiv
In the United States, gay men are at a disproportionately high risk of getting HIV;and AIDS. In 2016, 68% of all HIV infections in the U.S. affected men who have sex with men. The risk is even higher for gay black men. Why are gay men more likely to get HIV?
There are several reasons why gay and bisexual men are at higher risk of HIV than their straight counterparts. Some of the reasons are based on certain types of sex that result in greater risk of infection due to how HIV is biologically transmitted. Other reasons reflect social realities about how;men who have sex with men live in the world and are treated by society.
First Human Hiv Infection
Actor Rock Hudson was the first major public figure known to have died of AIDS. Tennis great Arthur Ashe also died from transfusion-related AIDS. Ryan White, a 13-year-old hemophiliac with AIDS, who eventually died, became famous for his fight to attend school. And basketball superstar Magic Johnson, 10 years after he announced that he was HIV positive, is still living a healthy life with the disease.
A plasma sample taken in 1959 from an adult male living in the Democratic Republic of Congo was found to contain HIV. The virus was found in tissue samples from an African American teenager who died in St. Louis in 1969, and HIV was found in tissue samples from a Norwegian sailor who died around 1976. Many scientists believe that HIV was probably introduced into humans around the 1940s or the early 1950s, although it has been suggested that the first case may actually have occurred in the 1930s.
Excerpted from The Complete Idiot’s Guide to Dangerous Diseases and Epidemics 2002 by David Perlin, Ph.D., and Ann Cohen. All rights reserved including the right of reproduction in whole or in part in any form. Used by arrangement with Alpha Books, a member of Penguin Group Inc.
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Ways Hiv Cannot Be Spread
HIV is not spread by:
- Air or water
- Mosquitoes, ticks or other insects
- Saliva, tears, or sweat that is not mixed with the blood of a person with HIV
- Shaking hands; hugging; sharing toilets; sharing dishes, silverware, or drinking glasses; or engaging in closed-mouth or social kissing with a person with HIV
- Drinking fountains
What Is The ‘four
In 1983, the Centers for Disease Control in the United States listed the main at-risk groups, including partners of people with AIDS, people who inject drugs, haemophiliacs and people who have recently been to Haiti. At the time that cases of AIDS began to emerge in the USA, the absence of definitive information about HIV and its link to AIDS, inflated the panic and stigma surrounding the epidemic. Before long people began to talk colloquially of a 4-H Club at risk of AIDS: homosexuals, haemophiliacs, heroin addicts and Haitians, contributing to further stigmatisation.21
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Why Is Haiti Significant
In the 1960s, the ‘B’ subtype of HIV-1 had made its way to Haiti. At this time, many Haitian professionals who were working in the colonial Democratic Republic of Congo during the 1960s returned to Haiti.13 Initially, they were blamed for being responsible for the HIV epidemic, and suffered severe racism, stigma and discrimination as a result.
HIV-1 subtype M is now the most geographically spread subtype of HIV internationally. By 2014, this subtype had caused 75 million infections.14
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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Hiv Originated With Monkeys Not Chimps Study Finds
Researchers have found new clues to the deadly disease’s origins.
Scientists now say that the simian immunodeficiency virus in chimpanzees , which is believed to have been transmitted to humans to become HIV-1the virus that causes AIDSdidn’t start its life in chimps.
Instead, it was a product of separate viruses jumping from different monkey species into chimps, where they recombined to form a hybrid virus, according to a new study.
Researchers believe the chimpanzee virus is a hybrid of the SIVs naturally infecting two different monkeys, the red-capped mangabey and the greater spot-nosed monkey . Chimps eat monkeys, which is likely how they acquired the monkey viruses. The hybrid virus then spread through the chimpanzee species, and was later transmitted to humans to become HIV-1.
The study suggests striking parallels between SIV infection of chimps and HIV infection of humans. Just as chimps acquired viruses from two different sources, humans are infected by two distinct AIDS viruses: HIV-1 and the less virulent HIV-2, which humans acquired from sooty mangabey monkeys.
“Because of the similarity between chimpanzees and humans, any virus that successfully adapts to spreading among chimps would be a candidate for a further jump to humansa potential HIV-3,” said Paul Sharp of the Institute of Genetics at University of Nottingham in England, who led the study.
Where Did The Virus Cross Into Humans
If SIV crossed in several places and then began to spread slowly, where are the most likely places for this to have occurred?
A review of sub-type diversity by Martine Peeters found that the greatest diversity lies in the region of Kinshasa, and that Zaire generally shows the greatest degree of sub-type diversity of any region in Africa. But does this necessarily make Zaire the ancestral hearth of HIV, or just the crossroads at which a number of viruses were able to come together?
At the moment this question is still highly debatable. As sequence information accumulates and phylogenetic dating becomes more sophisticated it may become easier to answer, but at present any assertions on the location of first transfer are highly speculative.
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Why Do We Care Does All This Research Into How The Virus Got Started Tell Us Anything About How To Stop It
Hunting chimps in West Central Africa.
Research into the HIV’s origins may eventually yield practical results. It could help scientists understand why HIV’s viral ancestor, SIV, doesn’t kill or even sicken chimps who carry it. With that knowledge, researchers might be able to make drugs with fewer side effects, or broad-spectrum vaccines that protect against all the strains of the disease that infect people today.
Korber suggests that in an era of emerging diseases, looking back on the virus’ shadowy origins offers a “history lesson,” or perhaps even a fable, with a moral attached. By the time doctors realized that HIV/AIDS existed, it had already taken up permanent residence in humans. They couldn’t have known about it before then, but, Korber says, at least now they know to be wary as the virus continues its shape-shifting spread around the globe. “The fact that it could be with us for quite a long time before we even realized it was there is kind of eye-opening,” she says. “I think it’s something to keep us on our toes. It helps us understand that we can be surprised.” And of course, HIV research may have a few surprises left for us, too.
Hivs Unusual Family Tree
When epidemiologists talk about HIV, the numbers are staggering. An estimated 34 million people around the world were living with HIV in 2011, according to a report from the United Nations.
But evolutionary biologists are concerned with smaller figures.
Two: the number of HIV precursor strains that merged their genetic material inside a chimpanzee to create a much more virulent bug, deadly to chimps â and which ultimately spawned HIV.
One: the unfortunate chimp first infected with that new virus, known as simian immunodeficiency virus cpz, or SIVcpz.
Four: the number of times HIV jumped from chimp to human. HIV likely arose from blood contact when humans handled bushmeat from SIV-infected apes.
In some ways itâs surprising that HIVâs chimp precursor hasnât cropped up more often, said Fred Hutchinson Cancer Research Center virologist Dr. Michael Emerman.
The birth of SIVcpz âwas a very unusual event, because it only happened one time that we know of in evolutionary history,â said Emerman, who studies the viral, chimp and human evolutionary steps that ultimately allowed HIV to come into the world. âAnd we know that there are lots of exposures, because chimpanzees eat a lot of monkeys and a lot of these monkeys have their own version of these SIVs.â
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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!
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 , 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.
Oral polio vaccine administration. Image credit: Julien;Harneis, via Wikimedia Commons.
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 origin, not the government. Everyone loves to hear about a good conspiracy theory, but it really does not add up here.;
Hiv/aids In The 1990s And 2000s
In 1991, the red ribbon became an international symbol of AIDS awareness.
In that year, basketball player Magic Johnson announced he had HIV, helping to further bring awareness to the issue and dispel the stereotype of it being a gay disease. Soon after, Freddie Mercurylead singer of the band Queenannounced he had AIDS and died a day later.
In 1994, the FDA approved the first oral HIV test. Two years later, it approved the first home testing kit and the first urine test.
AIDS-related deaths and hospitalizations in developed countries began to decline sharply in 1995 thanks to new medications and the introduction of HAART. Still, by 1999, AIDS was the fourth biggest cause of death in the world and the leading cause of death in Africa.