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Human immunodeficiency virus Introduction In 1983, scientists led by Luc Montagnier at the Pasteur institute in France, first discovered

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Human immunodeficiency virus Introduction In 1983, scientists led by Luc Montagnier at the Pasteur institute in France, first discovered the virus that causes AIDS. They called it lymphadenopathy-associated virus (LAV). A year later, Robert Gallo and Marvin Reitz of the United States, confirmed the discovery of the virus and they named it human T lymphotropic virus type III (HTL V-III). In 1986, both names were dropped in favour of the term human immunodeficiency virus (HIV). AIDS is thought to have originated in sub-Saharan Africa during the twentieth century. By the end of 2004, it was estimated that 40 million people were currently living with HIV. Women account for 46% of all adults living with HIV. It is estimated that 28 million people have died of AIDS. Young people (15-24 year olds) account for half of all new HIV infections. More than 6,000 people become infected with HIV every day. Of the 6.5 million people in developing and transitional countries who need life-saving drugs, only 1 million are receiving them. Causative organisms Diagram 1 HIV is a retrovirus. A retrovirus has some unique features; * Their genetic material is RNA instead of DNA * They contain the enzyme reserve transcriptase which enables the cell to make viral DNA from viral RNA * When the viral DNA is inserted into the host's cell's DNA it forms a provirus. ...read more.


* Oral sex- With an infected partner does carry some risk of infection though very rare. The virus could get into the blood if you have bleeding gums, tiny sores or ulcers in the mouth. The body fluids containing HIV include; * Blood transfusions- Some people have been infected through a transfusion of infected blood. * Blood products- such as those used by people with haemophilia. * Semen and possibly pre-seminal fluid * Vaginal secretion * Breast milk Over ways that HIV can be transmitted; * Injecting drugs- the virus can be passed by sharing needles, syringes, spoons, filters and water. * Mother to child transmission- an infected pregnant woman can pass the virus to her unborn child either before or during birth. * Infection in the health care setting- some health care workers have become infected with HIV by being stuck with needles containing HIV-infected blood. * Tattoos/piercing- if the equipment is not sterile, having a tattoo/piercing done could carry a very small risk. Clinical features The most common clinical problems that HIV sufferers is; * weight loss * Fungal nail infections * Oral ulcers * Angular cheilitis (inflammation of the mouth) * Herpes * Respiratory tract infections * Chronic diarrhoea * Fever * Thrush * TB * Pneumonia * Acute renal failure * Dementia There are some clinical problems caused by opportunistic infections. ...read more.


There are four main groups of anti-HIV drugs. They are; * Nucleoside/nucleotide reverse transcriptase inhibitors- They work by making sure that during replication, the DNA copy is faulty so the process cannot continue. * Non-nucleoside reverse transcriptors inhibitors- These also stop the HIV from replicating. They do it by inhibiting the action of the enzyme reverse transcriptase. * Protease inhibitor- Almost every living cell contains some type of protease. In the final stages of HIV replication, the infected human cell produces long chains of viral proteins. These must be cut up into smaller pieces from which to construct the cores of mature virus particles. Protease inhibitors prevent a special type of HIV protease from carrying out this process and so prevent the production of mature infectious viral particles. * Fusion or entry inhibitors- In order to enter a human cell, HIV must first attach itself to the cells surface and then fuse its envelope with the cell's membrane. The attachment process typically involves the binding of an HIV surface protein (gp 120) with a human cell surface protein (CD4) and then fusion process involves a HIV surface protein (gp 41). Entry inhibitors interfere with these proteins. So unlike the three other classes of drugs, entry inhibitors act against the HIV before it has enters the cell. Diagram 1 www.petech.ac.za Diagram 2 www.avert.org Graphs made using data from www.avert. ...read more.

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