CAUSES AND PREVENTION OF AIDS
AIDS is caused by the human
immunodeficiency virus (HIV) (right),
which consists of some nucleic acid
(genetic material) inside two protective
shells and an outer envelope. Full-
blown AIDS develops in only some
people infected with HIV.
lymphocyte (cell of the
HOW HIV AFFECTS THE IMMUNE SYSTEM
HIV enters the bloodstream and infects
cells that have CD4 receptors on their
surface, particularly CD4-lymphocytes,
which are responsible for fighting infection.
The virus attaches to and enters the
CD4-lymphocytes. It then loses its
protective shell, releasing its RNA and
reverse transcriptase (an enzyme).
Reverse transcriptase enables the viral
RNA to use the hostCD4-lymphocyte’s
genetic material to reproduce itself. The new
virus particles are released into the blood,
killing the infected CD4-lymphocyte.
When disease organisms invade,
immune responses may fail, due to a
shortage of CD4-lymphocytes. The disease
organism may then overwhelm the immune
system and lead to the features of AIDS.
PREVENTING THE SPREAD
Do not have sexual intercourse with
many partners, and especially not
with people known to have HIV,
without using a condom.
Do not use intravenous (IV) drugs.
Ifyou use IV drugs, do not share
needles or syringes.
Do not have sex with people who use
People with AIDS or who have had
positive HIV antibody test results
may pass the disease on to others
and should notdonate blood,
plasma, body organs, other tissues,
or sperm. They should not exchange
body fluids during sexual activity.
There is a risk of infecting (or being
infected by) others through sexual
intercourse, sharing needles, and,
possibly, exposure of others to
saliva through oral-genital contact
or “wet” kissing. Condoms
substantially reduce the risk
Toothbrushes, razors, or other
implements that could become
contaminated with blood should
not be shared.