Everything about the HIV virus
Date: 2 سال قبل
author: AmirAbad
HIV
HIV
(human immunodeficiency virus) is a virus that attacks cells that help
the body fight infection, making a person more vulnerable to other infections
and diseases. It is spread by contact with certain bodily fluids of a person
with HIV, most commonly during unprotected sex (sex without a condom or HIV
medicine to prevent or treat HIV), or through sharing injection drug equipment.
If
left untreated, HIV can lead to the disease AIDS (acquired immunodeficiency
syndrome).
The
human body can’t get rid of HIV and no effective HIV cure exists. So, once you
have HIV, you have it for life.
However,
by taking HIV medicine (called antiretroviral therapy or ART), people with HIV
can live long and healthy lives and prevent transmitting HIV to their
sexual partners. In addition, there are effective methods to prevent getting
HIV through sex or drug use, including pre-exposure prophylaxis
(PrEP) and post-exposure prophylaxis (PEP).
First
identified in 1981, HIV is the cause of one of humanity’s deadliest and most
persistent epidemics.
What
Is AIDS?
AIDS
is the late stage of HIV infection that occurs when the body’s immune
system is badly damaged because of the virus.
In the
U.S., most people with HIV do not develop AIDS because taking HIV medicine
every day as prescribed stops the progression of the disease.
A
person with HIV is considered to have progressed to AIDS when:
- the number of their CD4 cells falls
below 200 cells per cubic millimeter of blood (200 cells/mm3). (In someone
with a healthy immune system, CD4 counts are between 500 and 1,600
cells/mm3.) OR
- they develop one or
more opportunistic infections regardless of their CD4 count.
Without
HIV medicine, people with AIDS typically survive about 3 years. Once someone
has a dangerous opportunistic illness, life expectancy without treatment falls
to about 1 year. HIV medicine can still help people at this stage of HIV
infection, and it can even be lifesaving. But people who start ART soon after
they get HIV experience more benefits—that’s why HIV testing is so important.
How
Do I Know If I Have HIV?
The
only way to know for sure if you have HIV is to get tested. Testing is
relatively simple. You can ask virology labs for advice on HIV testing.
In
general, there are three main groups of tests used to diagnose HIV / AIDS:
· Antibody
test (antibody)
· Antigen
test
· PCR
test
In
an antibody test, the presence of antibodies produced and secreted into the
blood by the white blood cells of the immune system is checked.
In an antigen test, the blood is tested for
the presence of the virus itself. Antigen tests are also divided into two
groups: RT-PCR and P24.
PCR
tests the virus genome in a person's blood and is slightly more expensive.
In
most HIV-infected people, a series of specific antibodies develop within three
to 12 weeks after the initial infection. The initial diagnosis of HIV before
antibody change is made by measuring HIV-RNA or P24 antigen. Positive results
obtained by antibody or polymerase chain reaction (PCR) test are confirmed by
PCR or another antibody.
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