AIDS


AIDS (acquired immunodeficiency syndrome) is a disease caused by a
virus- HIV (human immunodiciency virus). The first cases in this country came to
light in the early eighties. Although the origins of AIDS remains uncertain it
is thought to have emerged decades ago in sub-Saharan Africa. There is a
closely related virus (simian immunodeficiency virus, or SIV) that is found
among monkeys in that particular area which AIDS is thought to have evolved from
(Combating AIDS 353). When the virus first emerged in the United States it was
localized to the male homosexual and IV drug user communities. This
localization very quickly disappeared .
AIDS is becoming a global epidemic. No country is safe from it. There
has been AIDS cases reported around the world, in such places as the Caribbean,
Southeast Asia, Southeast Mediterranean , and Oceania. This helps to show that
AIDS knows no geographical boundries (Folks). This disease has been likened to
the Black Plaque that decimated Europe during the middle ages. By April 1984,
scientists had identified the virus responsible for AIDS and by March 1995
developed a blood test for it (Combating AIDS 355). This quick progress in the
battle even lead Heckler, the secretary of health and human services, to say
that a cure was just a few years away. Today, no cure is available and no sure
treatment for AIDS symptoms is at hand. People are still contracting and dying
from AIDS at an alarming rate. AIDS is a fatal disease that does not kill the
patient. Its principle source of infection is the HIV virus which is a
retrovirus. This means that the protein coat contains RNA instead of DNA and
when the virus injects its genetic material into the host cell, it must first
cause the cell to transcribe, using a unique enzyme called reverse transcriptase,
it into complementary- DNA (c-DNA) before replication can occur. The virus is
spherical in shape and is made of two parts: an envelop and core. The envelop
is similar to a typical cell membrane (bilipid layer) imbedded with three
proteins. The core section is bullet-shaped surrounded by a protein. Inside is
the genetic material, RNA, covered by another protein (Combating AIDS 354). The
HIV virus attacks the human helper T-cell or CD4-lymphocyte (part of the human
immune defense system). This cell normally attacks and destroys foreign
proteins and viruses. The normal CD4 T-lymphocyte is impervious to the HIV
virus but if this cell produces a CD4 receptor molecule the HIV virus then has
an entry into the cell. It attaches to the CD4 receptors on the cell surface.
A portion of the virus then penetrates the cell membrane, fuses with it and then
the HIV virus injects its core into the cell. Proteins in the core cause the
receptor cell to manufacture the viral c-DNA. This c-DNA then becomes a part of
the cells genetic material. When this happens what is known as a provirus is
formed. This provirus can remain unexpressed for years which is why a lot of
HIV positive people do not show AIDS symptoms for years. When some activator
stimulates the provirus, then viral RNA and the HIV proteins are synthesized and
new HIV viruses are produced (Nowak 964).
When activated, the virus causes a suppression of the immune system so
that one or more "opportunistic" diseases can gain a foothold. It is one of
these diseases which eventually kills the patient. An "opportunistic " disease
is one which a normal person\'s immune system can successfully defend against.
When something occurs that damages the immune system, then these diseases abound
(Folks).
One of the symptoms of full blown AIDS is dementia. This was thought to
be caused by encephalitis (inflammation of the brain). New evidence suggests
that the AIDS virus itself destroys neurons in the brain even though it does
not infect them. In laboratory findings the level of neurons in the brains of
dead AIDS patients was forty percent less than in non AIDS brains. The brains
of dead AIDS patients showed signs of HIV but the majority did not show signs of
encephalitis. It is proposed that the protein coat on HIV may interfere with
VIP (a brain protein) which some neurons need in order to send signals (Walker
311).
There are many areas of research in determining what causes the
activation of HIV. New evidence supports the theory that there is a cofactor
involved with the accelerated onset of AIDS. This cofactor is thought to be a
mycoplasma-a primitive bacteria. The effect seems to be indirect. The
mycoplasma seems to stimulate the cell to produce substances called cytokine.
Certain