Back to Infectious Diseases
Acquired immunodeficiency syndrome occurs as a result of
infection with HIV (human immunodeficiency virus). It belongs to
the family of human retroviruses and the subfamily of lentiviruses.
There are 2 types of HIV that result in AIDS in humans:
Mode of transmission
Sexual transmission: both homosexual and
heterosexual. It is particularly more common among homosexual
men during receptive anal intercourse. Vaginal transmission to
both partners is a common mode of transmission. Oral sex is a
much less effective mode of transmission although there have
been documented cases.
Transmission through HIV contaminated
Occupational transmission: Health care
worker and lab worker maybe infected. Infections resulting
from self puncture resulting from a needle or a sharp object
is rather low being estimated at a rate of approximately
Vertical transmission from the mother to
the fetus (through placental blood) or infant (through breast
There is no convincing evidence of
transmission through other body fluids (e.g. saliva).
Mechanism of disease
The hallmark of HIV disease is a profound immunodeficiency
resulting primarily from a progressive deficiency of a the
subset of T lymphocytes referred to as helper T cells,
or inducer T cells. This subset of T cells is
identified by the presence of a the CD4 molecule on its
surface which also serves as the primary cellular receptor for
retroviral syndrome: affects 50% of those infected and starts 3 to 6 weeks
after primary infection.
lymph node enlargement
disease (fever, loss of 10% body weight,
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Diagnosis and screening
Using the CDC system for diagnosis of AIDS, any HIIV-infected individual with
a CD4+ T cell count of <200/uL has AIDS by definition, regardless of the
presence of symptoms or opportunistic diseases.
The currently used screening methods include various ELISA techniques that
may require confirmation with Western Blot or other tests such as DNA PCR, RNA
PCR, the (b)DNA assay, or p24 antigen capture that usually take days.
There is currently no cure or vaccine for HIV or AIDS. Newer treatments,
however, have played a part in delaying the onset of AIDS, on reducing the
symptoms, and extending patients' life spans. Over the past decade the success
of these anti-retroviral treatments in prolonging, and improving, the quality of
life for people with AIDS has improved dramatically.
Current optimal treatment options consist of combinations ("cocktails") of
two or more types of anti-retroviral agents such as two nucleoside analogue
reverse transcriptase inhibitors (NRTIs), and a protease inhibitor. Patients on
such treatments have been known to repeatedly test "undetectable" (that is,
negative) for HIV, but discontinuing therapy has thus far caused all such
patients' viral loads to promptly increase. There is also concern with such
regimens that drug resistance will eventually develop. In recent years the term
HAART (highly-active anti-retroviral therapy) has been commonly used to describe
this form of treatment. The majority of the world's infected individuals,
unfortunately, do not have access to medications and treatments for HIV and
There is ongoing research into developing a vaccine for HIV and in developing
new anti-retroviral drugs. Human trials are currently underway. Research to
improve current treatments includes simplifying current drug regimens to improve
adherence and in decreasing side effects.