What Is The Evidence That Hiv Causes Aids
The epidemic of HIV and AIDS has attracted much attention both within and outside the medical and scientific communities. Much of this attention comes from the many social issues related to this disease such as sexuality, drug use, and poverty. Although the scientific evidence is overwhelming and compelling that HIV is the cause of AIDS, the disease process is still not completely understood. This incomplete understanding has led some persons to make statements that AIDS is not caused by an infectious agent or is caused by a virus that is not HIV. This is not only misleading, but may have dangerous consequences. Before the discovery of HIV, evidence from epidemiologic studies involving tracing of patients sex partners and cases occurring in persons receiving transfusions of blood or blood clotting products had clearly indicated that the underlying cause of the condition was an infectious agent. Infection with HIV has been the sole common factor shared by AIDS cases throughout the world among men who have sex with men, transfusion recipients, persons with hemophilia, sex partners of infected persons, children born to infected women, and occupationally exposed health care workers.
The conclusion after more than 28 years of scientific research is that people, if exposed to HIV through sexual contact or injecting drug use for example, may become infected with HIV. If they become infected, most will eventually develop AIDS.
Origin And Distribution Of Sivgor
HIV-1 origins. The phylogenetic relationships of representative SIVcpz, HIV-1, and SIVgor strains are shown for a region of the viral pol gene . SIVcpz and SIVgor sequences are shown in black and green, respectively. The four groups of HIV-1, each of which represents an independent cross-species transmission, are shown in different colors. Black circles indicate the four branches where cross-species transmission-to-humans has occurred. White circles indicate two possible alternative branches on which chimpanzee-to-gorilla transmission occurred. Brackets at the right denote SIVcpz from P. t. troglodytes and P. t. schweinfurthii , respectively. The phylogenetic tree was estimated using maximum likelihood methods . The scale bar represents 0.05 nucleotide substitutions per site.
Was Hiv Created In A Lab
No. HIV is a virus that has evolved over time and though it became a global pandemic only recently in human history, its origins are much older and found in nature.How can I tell if I’m infected with HIV?
The only way to know if you are infected is to be tested for HIV infection. You cannot rely on symptoms to know whether or not you are infected. Many people who are infected with HIV do not have any symptoms at all for 10 years or more.
The following may be warning signs of advanced HIV infection:
- rapid weight loss
- recurring fever or profuse night sweats
- profound and unexplained fatigue
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Homeless People And Intravenous Drug Users In New York
A volunteer social worker called Betty Williams, a Quaker who worked with the homeless in New York from the seventies and early eighties onwards, has talked about people at that time whose death would be labelled as “junkie flu” or “the dwindles”. In an interview for the Act Up Oral History Project in 2008, she said: “Of course, the horror stories came, mainly concerning women who were injection-drug users … who had PCP pneumonia , and were told that they just had bronchitis.” She continues: “I actually believe that AIDS kind of existed among this group of people first, because if you look back, there was something called junkie pneumonia, there was something called the dwindles that addicts got, and I think this was another early AIDS population way too helpless to ever do anything for themselves on their own behalf.”
Julia Epstein writes in her book Altered Conditions: Disease, Medicine and Storytelling that: “As we uncover more of the early history of HIV infection, it becomes clear that by at least the 1970s the virus was already making major inroads into the immune systems of a number of diverse populations in the United States and had for some time been causing devastation in several countries in Africa.”
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.
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Groups And Subtypes Of Hiv
Genetic studies have led to a general classification system for HIV that is primarily based on the degree of similarity in viral gene sequence. The two major classes of HIV are HIV-1 and HIV-2. HIV-1 is divided into three groups, known as group M , group O , and group N . Worldwide, HIV-1 group M causes the majority of HIV infections, and it is further subdivided into subtypes A through K, which differ in expression of viral genes, virulence, and mechanisms of transmission. In addition, some subtypes combine with one another to create recombinant subtypes. HIV-1 group M subtype B is the virus that spread from Africa to Haiti and eventually to the United States. Pandemic forms of subtype B are found in North and South America, Europe, Japan, and Australia. Subtypes A, C, and D are found in sub-Saharan Africa, although subtypes A and C are also found in Asia and some other parts of the world. Most other subtypes of group M are generally located in specific regions of Africa, South America, or Central America.
In 2009 a new strain of HIV-1 was discovered in a woman from Cameroon. The virus was closely related to a strain of SIV found in wild gorillas. Researchers placed the new virus into its own group, HIV-1 group P, because it was unique from all other types of HIV-1. It was unclear whether the newly identified virus causes disease in humans.
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.
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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.
Why Do Scientists Look At Recent Samples Of Hiv To Determine The Virus’ Overall Age Wouldn’t It Be Better To Use Older Samples That Haven’t Had As Much Time To Mutate
It would, but scientists don’t have that luxury. Other than the 1959 sample, there are very few preserved specimens of HIV-infected tissue that predate the early ’80s, when the virus was first recognized by health authorities. Researchers still hope there are forgotten samples in African freezers. “There has to be some serum or plasma somewhere, and given modern technology we could fish out the virus,” says Dr. David Ho, director of the Aaron Diamond AIDS Research Center and one of the world’s leading authorities on HIV.
But even if those samples are found someday, they won’t necessarily yield definite answers about the virus’ age, says Korber: “Often, you can’t get anything out of samples like that.” Most African samples are made of blood serum, and serum samples contain viral RNA, which degrades much faster than the DNA found in tissue samples. In fact, says Ho, the 1959 sample, which was sequenced by his laboratory, was kept in a freezer but still didn’t survive the ravages of time. “It was completely dried up,” he says. “We were only able to get small pieces , and we had to stitch them together.”
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How Does Hiv Spread
HIV spreads when infected blood, semen or vaginal fluids enter the body. Because symptoms can be mild at first, people with HIV might not know they’re infected. They can spread HIV to others without knowing it.
HIV can spread:
- during sex
- through sharing needles for injecting drugs or tattooing
HIV also can pass from mother to child during pregnancy, childbirth, or breastfeeding.
HIV does not spread through:
- pee, poop, spit, throw-up, or sweat
- coughing or sneezing
- sharing eating utensils or drinking glasses
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.
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Nixon And The Special Virus Cancer Program
Another common AIDS conspiracy is that it was created as America was launching programs to help fight cancer during Richard Nixons presidency in the early 1970s. These theorists state that using a vaccine that was found in primates contained the ancestor virus of HIV. These viruses were tested in laboratories in the 1970s and were given to human subjects who were then infected with the toxic virus we know of as AIDS. Because of the timing of this right before AIDS was first discovered, this is a very popular HIV conspiracy that many people believed was covered up by our government.
Background To The Aids Conspiracy
Rock Hudson, an actor who died from AIDS complications in 1985
An epidemic that struck our nation in the 1980s was the AIDS epidemic. While HIV/AIDS it still a deadly disease worldwide, it is currently controlled better in America than other parts of the world, mainly Africa. While much of it can now be maintained and treated, it was a disease that took the United States by storm in the 1980s as it killed many Americans in a short time period. The HIV/AIDS scare of the 1980s and 1990s reached dramatic heights when several famous actors and musicians died from this disease. The picture to the right is of famous Hollywood actor Rock Hudson, who passed away from complication of the disease in October of 1985.
While AIDS occurred in a number of individuals, the most widely affected were the homosexual community and African-Americans. The United States Government has long proclaimed that the origins of AIDS were coming from primates in Africa in the 1930s. The support was that humans who interacted with these primates were passed this deadly virus. The AIDS virus could then be passed to other humans through sexual intercourse or some type of blood transfusion. While this is the common idea shared by most, there are others who have their own HIV conspiracy theories that are quite different from what most scientists have suggested and have a belief that aids is man made.
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Where Did Hiv Come From
A zoonosis is an infection or infectious disease that is transmissible from vertebrate animals to people.
The best accepted theory about the origin of HIV is that it is a descendant of a closely related virus, simian immunodeficiency virus , which infects monkeys. Researchers have known for a long time that certain viruses can pass from animals to humans, a process that is called zoonosis. HIV may have crossed over from chimpanzees as a result of a human killing a chimp and eating it for food.
In 1999, researchers confirmed that tissue from a chimpanzee carried a form of SIV that was nearly identical to an aggressive form of HIV, HIV-1. It appears highly likely chimpanzees were the source of HIV-1, and that the virus at some point crossed species from chimpanzees to humans. We cannot say for sure when the virus first emerged, but it is clear that HIV started to infect humans and became epidemic in the middle of the twentieth century.
Why don’t mosquitoes transmit AIDS? The HIV virus does not multiply in mosquitoes. If a mosquito feeds on an HIV-infected human, the virus is treated like food and digested along with the blood meal. If the mosquito resumes feeding on a non-HIV-infected individual, too few particles are transferred to initiate a new infection.
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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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 , 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 arose from a single transmission event. M and N have been traced back to SIV infected chimpanzees , but the closest relatives of O and P have been found in gorillas.
Image credit: Chi King, via Wikimedia Commons.