HIV (human immunodeficiency virus) progressively destructs the immune system. AIDS (Acquired immunodeficiency syndrome) represents the last stages of infection by HIV. 35 to 40 million people are currently infected with HIV worldwide.
Transmission of the AIDS
The HIV virus is present in blood and other body fluids, and is mainly transmitted through the exchange of such fluids. Being mainly a sexually transmitted disease, HIV can be transmitted via semen, or vaginal fluids through unprotected vaginal, oral or anal sex. Transmission also occurs through blood-to-blood contact, for example contact of open wounds, health-care professionals who may be accidentally pricked by an infected needle, or between drug users who use needles. It has also been found that the virus can be transmitted from mother to child through breast feeding.
Structure of AIDS/HIV and how the structure contributes to infection
The virus consits of genetic material in the form of RNA (ribonucleic acid). This RNA is contained in a protein coat known as a capsid. Surrounding the capsid is the envelope, a membrane pierced with glycoproteins.
The glycoproteins act as a key to the host cells. The glycoproteins bind to receptors on the outer surface of the host cells, this causes the cell to let the virus in through a process called reptor-mediated endocytosis. The virus then sheds the capsid, and begins the process of replicating itself.
The virus uses an enzyme called reverse transcriptase make a copy of DNA from it’s RNA. The viral DNA is then incorporated into the host cell DNA. As the host cell undergoes its normal process of DNA replication and cell division, it also replicates and distributes the integrated viral DNA. The viral DNA is then used to construct more RNA molecules and protein coats for each copy. The resulting HIV viruses bud off from the host cells are travel through the blood to infect other cells.
HIV viruses mainly destruct the immune system. They bind to CD4 receptors on white blood cells called helper T cells. The virus then enters the cell via receptor mediated endocytosis. As the viruses bud, they damage helper T cell membranes, rendering the cell useless. Also, the body uses its own defence system to rid itself of infected cells. Ultimately more helper T cells are destroyed, but not all the viruses they contain are destroyed. The body adapts and begins to replace helper T cells as fast as possible, but gradually this ability is exhausted, and the number of helper T cells begins to wane.
AIDS Treatment
Currently, there is no known cure for HIV/ AIDS. The available treatments help to extend the life of people who are infected.
Protease inhibitors
Proteases are enzymes which the virus requires to assemble more protein coats. These drugs disrupt this enzyme and reduce the virus’ ability to use it. The available medications in this category include indinavir, ritonavir, nelfinavir and saquinavir.
Reverse transcriptase inhibitors
These drugs interfere with reverse transcriptase, thereby interfering with the virus’ ability to make a DNA copy of its RNA.
HAART treatment
Highly Active Antiretroviral Therapy uses a combination of protease inhibitors and reverse transcriptase inhibitors. This treatment has been found to be extremely effective as it reduces the viral load and boosts the levels of helper T cells, therefore delaying the progression of the disease. Some patients have seen remission or disappearance of the infections.
Although the development of drugs is a positive step, the downside is that they are not accessible to the majority of patients due to the high cost.
HIV/ AIDS is a disease that is causing havoc worldwide. So far no sure cure has been found but treatments are available that will delay the disease’s progression.
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