HIV stands for Human Immunodeficiency Virus
HIV is a virus. Viruses like HIV cannot reproduce on their own, they need to infect cells of living organisms in order to replicate (make new copies of themselves). The human immune system usually fights viruses fairly quickly, but HIV attacks the immune system that normally fights the virus itself.
The connection between HIV and AIDS
AIDS is caused by HIV damaging the immune system cells until the immune system can no longer fight off other infections that it would usually be able to prevent. If left untreated, it takes about ten years on average for someone with HIV to develop AIDS. However, this timeframe is based on the person with HIV having a well-balanced diet and not engaging in unprotected sexual intercourse. Someone who is malnourished may progress to AIDS rapidly.
Transmission of HIV
HIV is found in the blood, sexual fluids and in the breast milk of an infected individual. HIV transmission occurs when a sufficient quantity of these fluids enter into someone else’s bloodstream. A person can become infected with HIV by:
- Being in contact with an infected person’s blood. If sufficient blood from an individual who is infected with the HIV virus enters someone else’s body, then HIV can be transmitted to the individual.
- Use of infected blood products, e.g. blood transfusion.
- Use of contaminated needles, e.g. drug users
- From mother to child: HIV can be transmitted from an infected woman to her baby during pregnancy (if not put on HAART), delivery and breastfeeding.
- Having unprotected sexual intercourse with an infected person.
Prevention of HIV/AIDS
There is currently no cure or vaccine for HIV/AIDS. Education about HIV and how it is spread is an essential part of prevention.
Beginning HIV treatment
HIV infection is a chronic and manageable condition. People with HIV can live long and healthy lives with access to antiretroviral treatment. The average person is recommended to start treatment when their CD4 count drops to between 350 -500 cells/mm.
Types of HIV tests
There are a number of tests that are used to find out whether a person is infected with HIV. These tests include the HIV antibody test, p24 antigen test, Elisa and rapid tests. A CD4 and viral blood test are used once a person has been diagnosed with HIV for monitoring.
HIV was isolated as a virus in 1983. Scientific theory believes HIV originated in the central and western parts of Africa as a crossover (zoonosis) between primates and human beings, the original virus being SIV, a virus that infected human beings and found a willing host. There is substantial collaborative evidence to support this theory.
The exact origins of HIV are somewhat contentious, especially to people in Africa, where the virus is thought to have evolved separately in two different regions of the continent. A common misbelief in the USA and Europe is that HIV was man-made to control homosexual populations, prostitutes and intravenous drug users—whilst in Africa, it is a common misbelief that HIV was spread by colonialists to bring about the demise of indigenous populations.
There are currently two known types of HIV: HIV1 and HIV2. HIV1 is thought to have originated in central Africa from chimpanzees, while HIV2 is thought to have originated in western Africa from the Sooty Mangabey monkey.
HIV1 is the more aggressive of the two and is the predominant form of the virus in most of the world. To further complicate matters there are different subtypes, indicating that different forms may have evolved through more than one crossover to human beings.
HIV belongs to a group of viruses called retroviruses that are otherwise found only in animals; HIV is currently the only retrovirus found in man.
The genetic material of viruses may be either DNA (also the genetic material of man) or RNA. HIV has RNA as the basis of its genetic material and must convert this to DNA in order to be compatible with, and take advantage of the human host. Retroviruses have a unique enzyme called reverse transcriptase that converts viral RNA to DNA as part of the infection and multiplication process to achieve this.
Why is HIV different?
Unlike other viruses, once in the host cell, HIV is able to remain there without completing its lifecycle. The virus becomes dormant and out of reach of the immune system (the immune system does not react to dormant threats). It is also able to integrate into the cellular DNA structure (especially the memory cells of the immune system) and can remain there for long periods of time, again outside the reach of the immune system.
The virus itself undergoes consistent changes in structure in response to the immune process. As a result, antibodies that may have been effective against the original virus become ineffective, and as the virus changes so the body has to produce new antibodies. The immune system thus remains in relentless pursuit of an organism that is able to evade the targeted antibodies produced, and the virus remains one step ahead.
Can HIV be defeated?
HIV cannot be eliminated from the body through any known treatment at present. Various drugs, however, are able to interfere with the HIV lifecycle, and more continue to be developed. Fairly recently, drugs were developed that can interfere with the reverse transcriptase enzyme and the protease enzyme. One drug is even known to be able to stop the fusion process. Drugs that stop integration and other stages of the HIV lifecycle are being developed, as are compounds that will prevent HIV attachment to targeted cells.
Although the development of an HIV vaccine has continued to elude science as a result of the highly variable nature of the virus, there are a number of candidate vaccines in development at present.