please answer my question guys co'z i really need it for my assignment in biology...tnx in advance Where did it probably originate?
Since AIDS was discovered in 1983, researchers have made significant progress in their understanding of the disease. Two distinct types of HIV have been identified thus far. HIV-1 and HIV-2 are thought to have a common ancestor and new evidence suggests that the viruses diverged sometime before the 1940s. Despite the considerable knowledge researchers have gained so far, a definite source for the HIV virus continues to elude them.
Though first identified in the United States, evidence points to a large region of Central Africa, including Zaire, Zambia, Uganda, Rwanda, and the Central African Republic, as the possible location of the origin of the AIDS pandemic.
It is now generally accepted that HIV is a descendant of simian immunodeficiency virus (SIV) (simian meaning monkey.) Certain SIVs closely resemble HIV-1 and HIV-2. In February 1999 it was announced that a group of researchers from the University of Alabama had studied frozen tissue from a chimpanzee and found that the SIV it carried was almost identical to HIV-1. It is claimed by the researchers that this shows that these chimpanzees were the source of HIV-1, and that the virus at some point crossed species from chimpanzee to human.
HIV-2 has an almost exact counterpart in a virus of the sooty mangabey, a type of African monkey. Western Africa, the habitat of the sooty mangabey, is also the area where vast majority of HIV-2 cases are located. HIV-2s connection to the sooty mangabey is probably the most compelling evidence for animal to man transfer of HIV.
This possible reservoir of infection and the type of human behaviour in certain areas noted here could have induced the transfer necessary to develop an endemic area of HIV infection from which a subsequent epidemic could emerge.
In addition to the theories of mainstream scientists, many other hypotheses have been put forward. Despite considerable evidence to the contrary, a small, but well-known group of scientists argue that HIV does not cause AIDS. They contend that AIDS is brought about by lifestyle factors such as drug use, inadequate nutrition, and contraction of multiple STDs. Among the general population, a significant percentage believes that HIV is manmade. The supposed motivations for the deliberate creation of HIV range from a plot by the US government to wipe out African-Americans, to a biological weapon developed by the Russian Scientists. Although many would dismiss such theories, they are widespread and may have important ramifications for treatment and prevention of HIV.
When did the virus (HIV-1) probably jump the specie barrier?
Scientists have long recognised the ability of certain viruses and other diseases to pass from animals to humans. This process is referred to as Zoonosis. Once an animal disease has infected people, it may then be passed from human to human.
Various means have been suggested through which SIV virus might have passed from primitives to humans. One theory is that the virus could have been transferred to humans while sooty mangabeys or chimpanzees were butchered for food or kept as pets. These chimpanzees are hunted in a very bloody way and eaten raw or sometimes people drink their blood. Another theory is based on particular ritualistic behaviour among natives living in remote central Africa, which involves the use of monkey blood in sexual customs.
The most controversial theories contended that medical science had played a role in introducing HIV into the human population. The most well known of the human error theories is that of polio vaccines, which were given to many Africans in the 1950s, could have been contaminated with HIV, as the vaccines were prepared using monkey kidneys.
To work out when the virus jumped the specie barrier we can look at three of the earliest known instances of HIV infections:
-HIV found in a tissue samples from a Norwegian sailor who died around 1976. He had sailed to African ports and had contracted sexually transmitted diseases at least twice. Tissue samples were tested and found to have been infected by a strain of HIV-1 that is common to West Africa.
-Secondly, HIV found in tissue samples from an African-American teenager who died in St. Louis in 1969. This is the oldest suspected case in America. HIV or a closely related virus was found in tissue samples from this young man that had been frozen at the time of his death. This case indicates that HIV was present in the United States before the 1970s.
-Thirdly, the earliest and most compelling evidence of HIV infection is that of a plasma sample taken in 1959 from an adult male living in what is now the Democratic Republic of Congo. Researchers believe that the ancestor of this strain may date to the 1940s or 1950s and were introduced into humans a decade or more earlier.
There is currently no vaccine or cure for HIV or AIDS. The only known methods of prevention are based on avoiding exposure to the virus or, failing that, an antiretroviral treatment directly after a highly significant exposure, called post-exposure prophylaxis (PEP).[65] PEP has a very demanding four week schedule of dosage. It also has very unpleasant side effects including diarrhea, malaise, nausea and fatigue.[73]
Current treatment for HIV infection consists of highly active antiretroviral therapy, or HAART.[74] This has been highly beneficial to many HIV-infected individuals since its introduction in 1996 when the protease inhibitor-based HAART initially became available.[75] Current optimal HAART options consist of combinations (or "cocktails") consisting of at least three drugs belonging to at least two types, or "classes," of anti-retroviral agents. Typical regimens consist of two nucleoside analogue reverse transcriptase inhibitors (NARTIs or NRTIs) plus either a protease inhibitor or a non-nucleoside reverse transcriptase inhibitor (NNRTI). Because HIV disease progression in children is more rapid than in adults, and laboratory parameters are less predictive of risk for disease progression, particularly for young infants, treatment recommendations are more aggressive for children than for adults.[76] In developed countries where HAART is available, doctors assess the viral load, rapidity in CD4 decline, and patient readiness while deciding when to recommend initiating treatment.[77]
Abacavir - a nucleoside analog reverse transcriptase inhibitors (NARTIs or NRTIs)
Atazanavir - a protease inhibitor
HAART allows the stabilisation of the patient鈥檚 symptoms and viremia, but it neither cures the patient of HIV, nor alleviates the symptoms, and high levels of HIV-1, often HAART resistant, return once treatment is stopped.[78][79] Moreover, it would take more than the lifetime of an individual to be cleared of HIV infection using HAART.[80] Despite this, many HIV-infected individuals have experienced remarkable improvements in their general health and quality of life, which has led to the plummeting of HIV-associated morbidity and mortality.[75][81][82] In the absence of HAART, progression from HIV infection to AIDS occurs at a median of between nine to ten years and the median survival time after developing AIDS is only 9.2 months.[7] Still, for some patients - and in many clinical cohorts this may be more than fifty percent of patients - HAART achieves far less than optimal results. This is due to a variety of reasons such as medication intolerance/side effects, prior ineffective antiretroviral therapy and infection with a drug-resistant strain of HIV. However, non-adherence and non-persistence with antiretroviral therapy is the major reason most individuals fail to get any benefit from and develop resistance to HAART.[83] The reasons for non-adherence and non-persistence with HAART are varied and overlapping. Major psychosocial issues, such as poor access to medical care, inadequate social supports, psychiatric disease and drug abuse contribute to non-adherence. The complexity of these HAART regimens, whether due to pill number, dosing frequency, meal restrictions or other issues along with side effects that create intentional non-adherence also has a weighty impact.[84][85][86] The side effects include lipodystrophy, dyslipidaemia, insulin resistance, an increase in cardiovascular risks and birth defects.[87][88]
Anti-retroviral drugs are expensive, and the majority of the world's infected individuals do not have access to medications and treatments for HIV and AIDS.[89] Research to improve current treatments includes decreasing side effects of current drugs, further simplifying drug regimens to improve adherence, and determining the best sequence of regimens to manage drug resistance. Only a vaccine is postulated to be able to halt the pandemic. This is because a vaccine would possibly cost less, thus being affordable for developing countries, and would not require daily treatments.[89] However, after over 20 years of research, HIV-1 remains a difficult target for a vaccine.[89]
A number of studies have shown that measures to prevent opportunistic infections can be beneficial when treating patients with HIV infection or AIDS. Vaccination against hepatitis A and B is advised for patients who are not infected with these viruses and are at risk of becoming infected.[90] In addition, AIDS patients should receive vaccination against Streptococcus pneumoniae and should receive yearly vaccination against influenza virus.[citation needed] Patients with substantial immunosuppression are also advised to receive prophylactic therapy for Pneumocystis jiroveci pneumonia (PCP), and many patients may benefit from prophylactic therapy for toxoplasmosis and Cryptococcus meningitis.
Various forms of alternative medicine have been used to try to treat symptoms or to try to affect the course of the disease itself, although none is a substitute for conventional treatment.[90] In the first decade of the epidemic when no useful conventional treatment was available, a large number of people with AIDS experimented with alternative therapies. The definition of "alternative therapies" in AIDS has changed since that time. Then, the phrase often referred to community-driven treatments, untested by government or pharmaceutical company research, that some hoped would directly suppress the virus or stimulate immunity against it. These kinds of approaches have become less common over time as the benefits of AIDS drugs have become more apparent. Examples of alternative medicine that people hoped would improve their symptoms or their quality of life include massage, herbal and flower remedies and acupuncture;[90] when used with conventional treatment, many now refer to these as "complementary" approaches. None of these treatments has been proven in controlled trials to have any effect in treating HIV or AIDS directly.[91] However, some may improve feelings of well-being in people who believe in their value. Additionally, people with AIDS, like people with other illnesses such as cancer, sometimes use marijuana to treat pain, combat nausea and stimulate appetite. Simien is a mountain region in Ethiopia.Also I very much doubt that lifestyle factors instead of the HIV virus cause AIDS that has well been researched.Otherwise a very good answer! Report It
Scientists are not yet 100% sure where AIDS came from exactly.There are viruses very similar that live in monkeys such as the Simien Monkey Virus.Green Baboons are known to be able to carry the AIDS virus but it does them no harm.
A lot of extensive research has yet to be done before doctors can effectively cure the disease for 100% .As it is now the virus can be fought off with certain medications so a person will carry it but will not fall sick as long as he takes his medication.Certain infections are lethal for a person that has AIDS because of the immune-deficiency.Toxoplasmosis for instance.It is a very complicated matter really. There are no drugs to prevent AIDS. It's an illness spread through body fluids like blood and semen. To prevent infection don't engage in sexual activity with an infected person and avoid their above mentioned fluids. AIDS was originally affiliated strictly with homosexual men and it was introduced into the straight society by the bi-sexual men and drug users who shared needles with infected persons and blood donations from infected persons. Now blood is screened thouroughly for this and other illnesses. I'm sure there is an internet site that can give you much more scientific information on this subject. Try the CDC. Most scientists working in the field believe that AIDS originated in Africa in certain monkeys. It was probably transmitted to humans by bites and then spread among humans by sexual contact.
There are no drugs that prevent AIDS in the sense of providing immunity but there are some drugs that delay or suppress the symptoms for a time. These drugs have been developed by pharmaceutical companies or medical research labs in several different countries. |
