Pathogenicity Of Siv In Non
In most non-human primate species, natural SIV infection does not cause a fatal disease . Comparison of the gene sequence of SIV with HIV should, therefore, give us information about the factors necessary to cause disease in humans. The factors that determine the virulence of HIV as compared to most SIVs are only now being elucidated. Non-human SIVs contain a nef gene that down-regulates CD3, CD4, and MHC class I expression most non-human SIVs, therefore, do not induce immunodeficiency the HIV-1nef gene, however, has lost its ability to down-regulate CD3, which results in the immune activation and apoptosis that is characteristic of chronic HIV infection.
In addition, a long-term survey of chimpanzees naturally infected with SIVcpz in Gombe, Tanzania found that, contrary to the previous paradigm, chimpanzees with SIVcpz infection do experience an increased mortality, and also suffer from a Human AIDS-like illness. SIV pathogenicity in wild animals could exist in other chimpanzee subspecies and other primate species as well, and stay unrecognized by lack of relevant long term studies.
Stigma In The Early Years
When the first few cases of AIDS emerged, people believed the disease was only contracted by men who had sex with men. The CDC called this infection GRIDS, or gay-related immunodeficiency syndrome. Shortly after, the CDC published a case definition calling the disease AIDS.
Public response was negative in the early years of the epidemic. In 1983, a doctor in New York was threatened with eviction, leading to the first AIDS discrimination lawsuit.
Bathhouses across the country closed due to high-risk sexual activity. Some schools also barred children with HIV from attending.
In 1987, the United States placed a travel ban on visitors and immigrants with HIV. President Obama lifted this ban in 2010.
The United States government resisted funding needle exchange programs due to the war on drugs. NEPs were shown to be effective at reducing HIV transmission. Some believe that this resistance accounts for 4,400 to 9,700 avoidable transmissions.
Origin And Distribution Of Sivcpz
Of the many primate lentiviruses that have been identified, SIVcpz has been of particular interest because of its close genetic relationship to HIV-1 . However, studies of this virus have proven to be challenging because of the endangered status of chimpanzees. The first isolates of SIVcpz were all derived from animals housed in primate centers or sanctuaries, although infection was rare in these populations. Collective analyses of nearly 2,000 wild-caught or captive-born apes identified fewer than a dozen SIVcpz positive individuals . Because other primate species, such as sooty mangabeys and African green monkeys, are much more commonly infected, both in captivity and in the wild , this finding raised doubts about whether chimpanzees represented a true SIV reservoir. To resolve this conundrum, our laboratory developed noninvasive diagnostic methods that detect SIVcpz specific antibodies and nucleic acids in chimpanzee fecal and urine samples with high sensitivity and specificity . These technical innovations, combined with genotyping methods for species and subspecies confirmation as well as individual identification, permitted a comprehensive analysis of wild-living chimpanzee populations throughout central Africa.
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History Of Hiv And Aids Overview
KEY POINTS:
The history of the HIV and AIDS epidemic began in illness, fear and death as the world faced a new and unknown virus. However, scientific advances, such as the development of antiretroviral drugs, have enabled people with access to treatment to live long and healthy lives with HIV.
Here, we go through the key historical moments that have defined the HIV epidemic over the past 30 years.
The Link Between Hiv And Siv
HIV is a type of lentivirus, which means it attacks the immune system. In a similar way, the Simian Immunodeficiency Virus attacks the immune systems of monkeys and apes.1
Research found that HIV is related to SIV and there are many similarities between the two viruses. HIV-1 is closely related to a strain of SIV found in chimpanzees, and HIV-2 is closely related to a strain of SIV found in sooty mangabeys.2
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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.
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In fact, some researchers now think the very first HIV infection in humans may have happened more than 100 years ago, in 1908 or earlier. In his new book, Spillover , author David Quammen describes how viruses that attack wild animals can sometimes spill over. That means the viruses can start attacking people.
Scientists found clues to suggest this happened with HIV after detecting a very similar virus in monkeys and in chimpanzees and other great apes. Its called SIV, which stands for simian immunodeficiency virus. The types most similar to HIV appeared in chimpanzees living in the African country of Cameroon. Based on the most recent research, Quammen reports, SIV may have spilled over in that part of Africa and become the virus known as HIV. How? Researchers believe a chimp somehow passed the virus on to a person.
Some scientists suspect that a hunter killed an infected chimp for food . In the process, the hunter could have come into contact with the animals infected blood. Perhaps the hunter had a cut or open sore. After jumping to people, Quammen writes, the virus then likely simmered for decades in nearby villages and slowly spread from one villager to another. If people died from other causes or from a second infection that overwhelmed their damaged immune systems, no one would have known they had HIV.
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Samples Collected From Wildlife In Thailand
While its true that most emerging diseases affecting humans come from wildlife, its often human behavior that is to blame for the spillover. Humans are tearing down forests and hunting, eating, and selling wild animals at unprecedented rates. Each exotic animal shipped across the ocean to be sold as a pet is an sveacasino opportunity for a new pathogen to take root in a new continent. Each tree ripped from its roots increases interactions between humans and wild animals, and thus the odds that viruses will find new populations to infect.
But the good news is: If were the ones causing the problem, were the ones who can stop it.
At EcoHealth Alliance, were striving toward a world where pandemics like the one caused by HIV/AIDS are a thing of the past. Join us.
How Was Hiv First Discovered
In the lead up to the discovery of HIV, immune system deficiency disorders were increasingly being detected within America. The causes of this increase were initially unknown. This led to a number of proposals concerning the possible origins of these disorders. Theories varied from ideas relating to immune system overload to the use of ‘poppers’ within the gay community as the cause of this disease.
Later data suggested that the disease was more likely caused by an infective agent. The HIV virus itself was first discovered in 1983 by two separate groups of scientists isolating it from patients presenting the symptoms of HIV infection. A medical test was then developed for HIV allowing better identification and tracking of those with the virus.
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Natural History Of Sivcpz Infection
Initially, SIVcpz was thought to be harmless for its natural host. This was because none of the few captive apes that were naturally SIVcpz infected suffered from overt immunodeficiency, although in retrospect this conclusion was based on the immunological and virological analyses of only a single naturally infected chimpanzee . In addition, SIV-infected sooty mangabeys and African green monkeys showed no sign of disease despite high viral loads in blood and lymphatic tissues , leading to the belief that all naturally occurring SIV infections are nonpathogenic. However, the sporadic prevalence of SIVcpz, along with its more recent monkey origin, suggested that its natural history might differ from that of other primate lentiviruses. To address this, a prospective study was initiated in Gombe National Park, Tanzania, the only field site where SIVcpz infected chimpanzees are habituated and so can be observed in their natural habitat.
How Did Aids Originate
While various sub-groups of the virus acquired human infectivity at different times the global pandemic had its origins in the emergence of one specific strain HIV-1 subgroup M in Léopoldville in the Belgian Congo now Kinshasa in the Democratic Republic. In Africa HIVthe virus that causes AIDShad jumped.
How The Aids Epidemic Really Began
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Where We Are Now: 2000
Since 2000, additional factors have begun contribute to the the global spread of HIV. Heroin addiction in Asia has been on the rise, which brought with it dirty needles and the risk of new infections. India suffered with over 2 million diagnoses alone, in spite of the government’s refusal to admit the epidemic had adversely affected the nation.
The WHO released its comprehensive report examining HIV and AIDS in all of its 25-year history in 2010. This report had good news for developed nations: by 2008, the U.S. domestic HIV infection rate was considered effectively stable, and has remained so to this day. The report also demonstrated that while insistent public awareness campaigns about safe sex and other methods of transmission had slowed the rate of HIV infection in developed countries, there was much to be done elsewhere.
Global Education and Aid Efforts
Under President Bush, the U.S. committed funds to help African countries, but the funds were mismanaged and the spread of HIV continued unabated. Of the 4.1 million cases in sub-Saharan Africa then, only 1% received the available drugs. This led to the WHO’s declaration of the failure to treat the 6 million AIDS patients living in developing nations as a global public health emergency.
HIV Denialism Disrupts Aid
By the time Mbeki was recalled from the presidency in 2008 and one year before the FDA approved its 100th HIV/AIDs drug, an estimated 16.9% of South Africans aged 15-49 were HIV positive.
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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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
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
This theory was later dubbed “Heart of Darkness” by Jim Moore, alluding to the book of the same title written by Joseph Conrad, the main focus of which is colonial abuses in equatorial Africa.
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Spread To The Western Hemisphere
Further isolated occurrences of this infection may have been emerging as early as 1966. The virus eventually entered gay male communities in large United States cities, where a combination of casual, multi-partner sexual activity and relatively high transmission rates associated with anal intercourse allowed it to spread explosively enough to finally be noticed.
Because of the long incubation period of HIV before symptoms of AIDS appear, and because of the initially low incidence, HIV was not noticed at first. By the time the first reported cases of AIDS were found in large United States cities, the prevalence of HIV infection in some communities had passed 5%. Worldwide, HIV infection has spread from urban to rural areas, and has appeared in regions such as China and India.
Hiv Pandemic’s Origins Located
The HIV pandemic with us today is almost certain to have begun its global spread from Kinshasa, the capital of the Democratic Republic of the Congo , according to a new study.
An international team, led by Oxford University and University of Leuven scientists, has reconstructed the genetic history of the HIV-1 group M pandemic, the event that saw HIV spread across the African continent and around the world, and concluded that it originated in Kinshasa. The teams analysis suggests that the common ancestor of group M is highly likely to have emerged in Kinshasa around 1920 .
HIV is known to have been transmitted from primates and apes to humans at least 13 times but only one of these transmission events has led to a human pandemic. It was only with the event that led to HIV-1 group M that a pandemic occurred, resulting in almost 75 million infections to date. The teams analysis suggests that, between the 1920s and 1950s, a ‘perfect storm’ of factors, including urban growth, strong railway links during Belgian colonial rule, and changes to the sex trade, combined to see HIV emerge from Kinshasa and spread across the globe.
A report of the research is published in this week’s Science.
One of the factors the team’s analysis suggests was key to the HIV pandemic’s origins was the DRC’s transport links, in particular its railways, that made Kinshasa one of the best connected of all central African cities.
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Origin Of Aids Linked To Colonial Practices In Africa
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Monday marks the 25th anniversary of the first report of AIDS. But only recently have scientists come to conclusions about where HIV came from. The current thinking is that the colonial horrors of mid-20th-century Africa allowed the virus to jump from chimpanzees to humans and become established in human populations around 1930. But there is still uncertainty as to why AIDS was first discovered in Los Angeles and New York, and not Cameroon, where scientists say it surely started.
LIANE HANSEN, host:
Twenty-five years ago tomorrow, doctors in Los Angeles first reported cases of what turned out to be the global catastrophe we now know as AIDS. Since then, 55 million people have been infected with the AIDS virus, and it kills around 8,000 people a day.
In the days surrounding the anniversary, NPR is broadcasting a number of stories about AIDS and its effect around the world. Today we examine its origins. Scientists, politicians, and conspiracy theorists have debated for years where AIDS began. Recently, researchers found the missing link: the immediate ancestor of the Human Immunodeficiency Virus.
NPR’s Richard Knox reports that the discovery clarifies the story of how a chimpanzee virus touched off the deadliest pandemic since the Middle Ages.
RICHARD KNOX reporting:
Prof. MOORE: For me, as a comparative primatologist, the more interesting question is why didn’t it happen sooner?
KNOX: With unsterilized syringes.
KNOX: And maybe dozens of others.