HIV

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HIV,

human immunodeficiency virus, either of two closely related retrovirusesretrovirus,
type of RNA virus that, unlike other RNA viruses, reproduces by transcribing itself into DNA. An enzyme called reverse transcriptase allows a retrovirus's RNA to act as the template for this RNA-to-DNA transcription.
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 that invade T-helper lymphocytes and are responsible for AIDSAIDS
or acquired immunodeficiency syndrome,
fatal disease caused by a rapidly mutating retrovirus that attacks the immune system and leaves the victim vulnerable to infections, malignancies, and neurological disorders. It was first recognized as a disease in 1981.
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. There are two types of HIV: HIV-1 and HIV-2. HIV-1 is responsible for the vast majority of AIDS in the United States. HIV-2, seen more often in western Africa, has a slower course than HIV-1. There are many strains of both types and the virus mutates rapidly, a trait that has made it especially difficult for researchers to find an effective treatment or vaccine. In many cases, a person's immune system will fight off the invasion of HIV for many years, producing billions of CD4 cells daily, always trying to keep up with the HIV's mutations, before it succumbs and permits the well-known signs of AIDS to develop.

HIV is especially lethal because it attacks the very immune system cells (variously called T4, CD4, or T-helper lymphocytes) that would ordinarily fight off such a viral infection. Receptors on these cells appear to enable the viral RNA to enter the cell. As with all retroviruses, once the RNA is inside the cell, an enzyme called reverse transcriptase allows it to act as the template for its own RNA to DNA transcription. The resultant viral DNA inserts itself into a cell's DNA and is reproduced along with the cell and its daughters. In 2012 the Food and Drug Administration approved a pill that combines two antiretroviral drugs, tenofovir and emtricitabine, for use in preventing infection with HIV, and two years later the Centers for Disease Control and Prevention called for the drug combination to be prescribed to uninfected patients who are at risk for AIDS in an effort to reduce number of new HIV infections.

The exact origin of the virus in humans is unclear. Scientists surmise that HIV-1 jumped from African chimpanzees, who harbor a similar strain of SIV (simian immunodeficiency virus), to humans via the butchering of meat or an animal bite. The first case documented in humans dates from 1959, but genetic analysis published in 2008 estimated that it originated some time between 1884 and 1924. A 2014 analysis suggested that the most widespread form of HIV-1 in humans originated in 1920s in what was then the Belgian Congo. AIDS is believed to have spread to the Caribbean in the 1960s and the United States in the early 1970s. The virus was isolated by Luc MontagnierMontagnier, Luc Antoine,
1932–, French virologist, M.D. Sorbonne, 1960. Montagnier was a researcher at the Medical Research Council at Carshalton, London (1960–63), the Institute of Virology in Glasgow, Scotland (1963–65), and the Curie Institute in Orsay,
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 of France's Pasteur Institute in 1983. It went through several name changes before the official name, human immunodeficiency virus, was agreed upon.

HIV

References in periodicals archive ?
Nigeria, like other African countries, has one of the highest prevalence of newly diagnosed HIV infections.
The fact that the authors were able to detect changes in such a resilient young population gives credence to the hypothesis that HIV infection is associated with brain alternations and corresponding abnormalities in cognitive abilities.
The most common method of transmission is unprotected sex, while the highest level of HIV infection is seen among men who have sex with other men.
WHO noted that HIV infection rates among men who have sex with men remain high nearly everywhere in the world.
This public health intervention might be particularly important among young black MSM in an HIV transmission network, who are disproportionately affected by new HIV infections and less likely to maintain sustained access to HIV medical care.
Three studies had enough details to let the researchers calculate the proportion of new HIV infections that could be attributed to infection with one or more of the 40 HPV types.
Another study explored why married girls in Kenya and Zambia had a higher risk for HIV infection.
The development of a safe, effective rectal microbicide would certainly reduce the amount of HIV infections among us and must be one of our top priorities,"
Data presented at 3rd International Congress on Drug Therapy in HIV Infection focuses on positive effects of IL-2.
age of first sexual activity, on the incidence of new HIV infections in each village.
While newspaper headlines trumpet the lessening of deaths from AIDS-related causes, the reality of rising HIV infection rates within communities of color is relegated to secondary mention.
Women whose HIV infections are detected early and who receive appropriate treatment survive as long as infected men.

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