An Analysis of Human Immunodeficiency Virus
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 lymphotrphic virus type III (HTL
V-III). In 1986, both names were dropped in favour of the term human
immunodefifciency 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.
HIV is a retrovirus. A retrovirus has some unique features:
· Their genetic material is RNA instead of DNA
· They contain the enzyme reverse 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
Retroviruses are characterised as being responsible for long duration
illnesses associated with a long period of incubation.
Source of infection
HIV begins its infection of a susceptible host cell by binding to the
CD4 receptor on the host cell. CD4 is present on the surface of many
lymphocytes, which are a crictical part of the body's immune system.
Recent evidence indicates that a coreceptor is needed for HIV to enter
the cell. This recognition of HIV coreceptors and progress in
understanding how HIV fuses with the cell has opened up new
possibilities for antiviral drugs. A number of new agents are being
designed to prevent infection by blocking fusion of HIV with its host
Following fusion of the virus with the host cell, HIV enters the cell.
The genetic material of the virus, which is RNA, is released and
undergoes reverse transcription into DNA. An enzyme in HIV called
reverse transcriptase is necessary to catalyze this conversion of
viral RNA into DNA. Once the genetic material of HIV has been changed
into DNA, this viral DNA enters the host cell nucleus where it can be
integrated into the genetic material of the cell. The enzyme integrase
catalyzes this process, once the viral DNA is integrated into the
genetic material of the host: it is possibe that HIV may persist in a
latent state for many years.
Activation of the host cells results in the transcription of viral DNA