A Look At The HIV-1 Virus

A Look At The HIV-1 Virus

There are actually two kinds of HIV which can infect you. They are appropriately known as the HIV-1 and HIV-2 viruses. Of the two, it is HIV-1 which is far more prevalent. It was found that, of the 33 million known incidences of HIV only between 1 and 2 million were caused by the HIV-2 virus. Thus it makes more sense to understand the HIV-1 virus as it is by far the more prevalent of the two variations.
A Look At The HIV-1 Virus

The HIV-1 virus is a single stranded RNA virus. 

It is of the family Retroviridaeand and genus Lentivirus. The way in which it operates is ingenious. It contains a transcriptase which allows the viral RNA to transcribe into DNA which is then incorporated into the genome of the infected individual. The virus targets specific cells within your immune system, namely the CD4 receptors and thus it infects the CD4-postitive T lymphocytes as well as a number of monocyte and macrophage cells. It can also infect the CD4-negative cells but does so in an inhibitory manner. There are a few subtypes of the HIV-1 Virus. The T-Tropic viruses infect lymphocytes, M-tropic viruses infect the macrophages. They make use of different receptors to do so as the different cells that they infect are susceptible to these receptors.

There are three phases to an HIV infection. 

There is the acute phase, latent phase and symptomatic chronic illness phase. The time period for each of these phases varies from person to person. A lot depends on the individual person as well as their environmental circumstances. The average time taken for AIDS, phase three, to develop is ten years without the benefit of antiretroviral treatment and the average expected lifespan after the development of AIDS is 1.3 to 3.7 years. This last is dependent on the CD4-cell count.

The first phase is characterised by the mass destruction of gut-associated memory T-cells. 

This leads to a very strong response from the immune system in the form of the generation of HIV specific CD8-positive T-cells. This causes the virus to become trapped in the dendritic tissues of the lymph cells. It does not eliminate the virus from the body however; it merely introduces the latent phase of the infection. It is during this initial phase that the effects of the transcriptase are started. The CD4-positive cells and macrophages are infected with the HIV DNA and this is where the virus hibernates for a period of time.

During the latent phase the virus is not active. 

It relies on natural cell replication within the human immune system to duplicate the infected CD4-positive cells and macrophages. This is how the HIV virus multiplies and eventually destroys the immune system.

The last phase is the phase where a person gets diagnosed with AIDS. 

The latent virus reactivates and overwhelms the immune system leading to increased vulnerability to other viruses such as those which cause a variety of CNS infections. Once a particular CD4 T-cell count is reached the infected individual is classed as having AIDS.

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