AIDS virus - traduzione in Inglese
![The [[phylogenetic tree]] of the SIV and HIV](https://commons.wikimedia.org/wiki/Special:FilePath/HIV-SIV-phylogenetic-tree straight.svg?width=200 "The [[phylogenetic tree]] of the SIV and HIV")
![surface]] of an infected [[macrophage]]. The HIV virions have been marked with a green [[fluorescent tag]] and then viewed under a fluorescent microscope.](https://commons.wikimedia.org/wiki/Special:FilePath/HIV on macrophage.png?width=200 "surface]] of an infected [[macrophage]]. The HIV virions have been marked with a green [[fluorescent tag]] and then viewed under a fluorescent microscope.")
![[[Clathrin-mediated endocytosis]]](https://commons.wikimedia.org/wiki/Special:FilePath/Itrafig2.jpg?width=200 "[[Clathrin-mediated endocytosis]]")
.jpg?width=200 "A diagram of the HIV spike protein (green), with the fusion peptide epitope highlighted in red, and a broadly neutralizing antibody (yellow) binding to the fusion peptide")
![[[Reverse transcription]] of the HIV [[genome]] into [[double-stranded DNA]]](https://commons.wikimedia.org/wiki/Special:FilePath/Reverse Transcription.png?width=200 "[[Reverse transcription]] of the HIV [[genome]] into [[double-stranded DNA]]")
![SIV]], the [[sooty mangabey]] source of [[HIV-2]], and the chimpanzee source of [[HIV-1]]](https://commons.wikimedia.org/wiki/Special:FilePath/SIV primates.jpg?width=200 "SIV]], the [[sooty mangabey]] source of [[HIV-2]], and the chimpanzee source of [[HIV-1]]")
Definizione
Wikipedia
The human immunodeficiency viruses (HIV) are two species of Lentivirus (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive. Without treatment, average survival time after infection with HIV is estimated to be 9 to 11 years, depending on the HIV subtype.
In most cases, HIV is a sexually transmitted infection and occurs by contact with or transfer of blood, pre-ejaculate, semen, and vaginal fluids. Non-sexual transmission can occur from an infected mother to her infant during pregnancy, during childbirth by exposure to her blood or vaginal fluid, and through breast milk. Within these bodily fluids, HIV is present as both free virus particles and virus within infected immune cells. Research has shown (for both same-sex and opposite-sex couples) that HIV is untransmittable through condomless sexual intercourse if the HIV-positive partner has a consistently undetectable viral load.
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.
