Differences between HIV and AIDS

Ever since its discovery in 1981, HIV/AIDS has killed almost 25
million people (as of 2008) but most people are still confused and do
not have a proper understanding of the difference between the two.

HIV is acronym for Human Immunodeficiency Virus. It is a lentivirus, a
genus of slow viruses of the Retroviridae family, generally known as a
retrovirus.  A retrovirus is an RNA virus that replicates in the host
cell and elicits reverse transcription in RNA strands of a normally
functioning cell. This basically violates the “central dogma of
biology.”

Transmission of HIV

HIV is transmitted through three main routes:

–       through the sexual route, due to unprotected sex
–       through infected blood – when it comes in contact with any open
wound, through a blood transfusion or through poor hygiene while using
injection equipment
–       from mother to child, during pregnancy, at childbirth or through
breast feeding

Two species of HIV are known and they are called HIV-1 and HIV-2.
HIV-2 transmits less frequently through the sexual and mother-to-child
route than HIV-1.

HIV Infection

HIV infection gradually decreases T-cell count and increases viral
load (the severity of infection). A T-cell is small lymphocyte that
develops in the thymus and directs the immune system’s response to
infected or malignant cells. Decrease in T-cell count renders the
immune system ineffective.

HIV infection has four stages – incubation, acute infection, the
latent stage and AIDS. In the incubation period, HIV infection does
not show any symptoms. Acute infection normally lasts for 28 days and
manifests symptoms that include fever, swollen lymph nodes, sore
throat, muscle pain, rash, general feeling of discomfort (out of
sorts) and sores in the mouth and esophagus. The latent stage may last
for 2 weeks or as long as twenty years or more but usually does not
present any significant symptoms.  The final and the most dreaded
stage of HIV infection is Acquired Immunodeficiency Syndrome,
generally known as AIDS.

What is AIDS?

As is evident from the name, AIDS is an immune disease. It is a
progressive disease that inhibits the effectiveness of the human
immune system, which in turn, greatly increases chances of
opportunistic infections and tumors.  Symptoms of AIDS are mostly due
to pathogens  disease causing bacteria, viruses, parasites and fungi
that are otherwise effectively controlled by a healthy immune system.
This can lead to a wide range of infections such as pulmonary,
gastrointestinal infections along with low grade fever and weight
loss. The patient also carries an enhanced risk of several types of
cancer. AIDS also has a neurological impact, either due to the
susceptibility of a weak nervous system or as a direct result of the
disease itself.  HIV/AIDS infected brain macrophages and microglia
lead to a metabolic brain disease known as AIDS dementia complex.

Some of the symptoms of the acute stage of HIV infection such as flu
like symptoms are similar to that of AIDS and also mimic many other
diseases. HIV infection does not occur unless there is a direct
exposure to the virus. A person with HIV infection is diagnosed as
having AIDS upon detecting the presence of one or more opportunistic
infections such as pneumonia or tuberculosis or an abnormally low
count of T-cells.

HIV/AIDS cannot be diagnosed on the basis of symptoms alone. The only
sure way of knowing is through an HIV test. There are a number of
tests such as a viral load test and the CD4 test. A home HIV
test
is fast and does not require visiting in person a clinic or
advanced laboratory facilities.