FREE ESSAY ON BIOLOGY PROJECT - A.I.D.S.

BIOLOGY PROJECT - A.I.D.S.

A.I.D.S. (Acquired Immune Deficiency Syndrome) is a very deadly disease. It is mostly
translated through the blood, sharing needles, sexual intercourse, and when an infected
mother breast-feeds her child. In this essay I will show you the causes, symptoms,
clinical progression, opportunistic infections, and the treatment you can receive to
delay the effects of aids.
Aids are caused by two viruses that belong to a group called retroviruses. Researchers in
France discovered this in 1983 and in the U.S. in 1984. This was known as the HIV-1. HIV
infects certain white blood cells. Some of these cells are the T-helper and the
macrophages, which play key roles in the immune system. HIV enters CD4 T-cells. The cell
makes more HIV and it spreads to other CD4 cells. The cells eventually die. Even though
the immune system makes millions of them everyday HIV kills them off as soon as they are
made. HIV must be present for the development of aids.
When you have HIV the symptoms you receive every few days tends to be much serious. Then
other symptoms are created and are much more severe. These include lymph glands,
tiredness, fever, loss of appetite and weight, diarrhea, yeast infections of the mouth
and vagina, and night sweats. The virus often infects the brain and nervous system. It
may cause memory disorders, movement and coordination problems, weight loss, decline in
health, and some cases, death.
The progression from the point of HIV infection to the clinical diseases that define aids
may take 6 to 10 years. This period of progression can be monitored using surrogate
markers or clinical endpoints.
When a person has aids the number of their CD4 T-cells, their white blood cells declines
in number. Within one to three weeks after infection with HIV, most people experience
nonspecific flu-like symptoms such as fever, headache, skin rash, tender lymph nodes, and
malaise. These symptoms last about one to two weeks. During this phase, known as acute
retroviral syndrome, HIV reproduces to very high concentrations, circulates through the
blood, and establishes infections throughout the body, especially in the lymph nodes. The
infected person's CD4 T-cell count falls briefly but then returns to near normal levels
as the person's immune system responds to the infection and limits the replication and
spread of HIV. Infected victims may be particularly contagious during this period.
Following acute retroviral syndrome, infected individuals enter a prolonged asymptomatic
phase that can last ten years or more. They remain in good health during this period,
with levels of CD4 T-cells in the low to normal range (500 to 750 cells per mm3 of
blood). Nevertheless, HIV continues to replicate during the asymptomatic phase, causing
progressive destruction of the immune system.
Eventually, the immune system declines and the person enters the early symptomatic phase.
This phase can last from a few months to several years and is characterized by rapidly
falling levels of CD4 T-cells (500 to 200 cells per mm3 of blood) and opportunistic
infections that are not life threatening. After the early symptomatic phase, the victim
experiences the extensive immune destruction and serious illness that characterize the
late symptomatic phase. This phase can also last from a few months to years, and the
affected victim may have CD4 T-cell levels below 200 per mm3 of blood along with certain
opportunistic infections that define AIDS. When victims enter this stage they loss a
continuous amount of weight and becomes fatigued most of the time. The immune system is
in a state of severe failure. The individual eventually enters the advanced AIDS phase,
in which CD4 T-cell numbers are below 50 per mm3 of blood, and death due to severe
life-threatening opportunistic infections and cancers occurs within one to two years. 
HIV makes people more open to diseases and such. In aids the gradual weakening of the
immune system allows increasingly severe infections and cancers to take effect and
eventually it leads to death. Death from aids do not come from the HIV viruses but comes
from opportunistic infections. These infections are called opportunistic because they
take advantage of the damage done to the immune system. The most common ones are
pneumonia, yeast infections of the esophagus, cytomegalovirus retinitis, kaposi's
sarcoma, and tuberculosis. 
There are three anti HIV drugs that are currently licensed by the U.S. 
Food and Administration. They are all RT inhibitors: AZT, DDL, and DDC. These drugs are
like DNA-chain terminators. Once the drug is inserted, no additional DNA bases can be
added, and therefore viral DNA synthesis is destroyed. But their effect is not that
great. They gave victims only around another 6 months of life. Another setback is that
when you take these drugs together or with others it may lower the effect. Also it may
cause birth problems.
A.I.D.S. is a very serious disease. Many people die from this disease. If you don't want
to catch it, don't use anyone's needle and use a condom during sexual intercourse, but
even these aren't 100% safe.