H = Infects only Human beings
I = Immunodeficiency virus weakens the
immune system and increases the risk of
V = Virus that attacks the body
“Acquired Immune Deficiency
A = Acquired, not inherited
I = Weakens the Immune system
D = Creates a Deficiency of CD4+ cells in
the immune system
S = Syndrome, or a group of illnesses
taking place at the same time
H.I.V (Human Immunodeficiency
Virus) is a unique type of virus (i.e. a
retrovirus) that invades the T- helper
cells (CD4 cells) in the body of the
host (defense mechanism of a
AIDS (Acquired Immunodeficiency
Syndrome) can be defined as
opportunistic infections and malignancies
that rarely occur in the absence of severe
Persons with positive HIV serology who
have ever had a CD4 lymphocyte count
below 200 cells/mcL or a CD4 lymphocyte
percentage below 14% are considered to
“Human Immunodeficiency virus”
There are two types of HIV.
HIV-1 is more common
HIV-1 is easily
HIV-1 is pathogenic in
Duration of HIV-1
infection is quite long.
HIV-1 is commonly seen
HIV-2 is found in West Africa,
Mozambique, and Angola.
HIV-2 is less easily
HIV-2 is less pathogenic.
Duration of HIV-2 infection is
HIV-2 is relatively rare and has
not been reported from India.
• Most cases in between 20-49 years.
• Rarely seen in childrens under 15 yrs.
• Seen in both males & females.
• Mostly in homosexual and bisexual mens.
• Male homosexuals & heterosexual partners.
• IV drug abusers, transfusion if infected blood
• HIV virus infects and destroys T-helper cells.
• It results in reduced cellular immunity.
Viral DNA is transcribed into mRNA
Integrase inserts viral DNA into Host DNA
RNA transcribes DNA by enzyme Reverse Transcriptase
RNA enters the human cell
HIV virus binds to CD4 receptors on surface of T cells.
Due to etiological factors
Destruction of T- helper cells and immune response
declines causing S/S.
Host cell is killed as viruses are released and budding
Polyprotein converts into genome n becomes permanent
part of cell’s genetic structure.
mRNA is translated into protein – polyprotein
It is first and foremost a
It can be transmitted by all
types of unprotected sex
i.e. vaginal, oral or anal.
It is acquired mainly
Sharing Needles (Without sterilization)
Increases the chances of contracting HIV
Transmitted by contaminated blood
transfusion of whole blood cells.
Also transmits through contact with
infected bodily fluids such as semen,
During pregnancy (through placenta)
The clinical features of HIV infection is
classified into four stages:
1. Initial infection
2. Asymptomatic stage
3. Symptomatic stage
Short, flu-like illness - occurs one to six
weeks after infection
Infected person can infect other people
Lasts for an average of ten years
This stage is free from symptoms
There may be swollen glands
The level of HIV in the blood drops to
HIV antibodies are detectable in the
The immune system deteriorates
Opportunistic infections and cancers
start to appear.
severe leading to
an AIDS diagnosis
too much as CD4
cells decrease in
TB is the most common opportunistic
infection in HIV and the first cause of
mortality in HIV infected patients (10-
10 million patients co-infected in the
Immunosuppression induced by HIV
modifies the clinical presentation of TB
The WHO clinical case defines adult
AIDS if the existence of at least two
major signs associated with at least
one minor sign in the absence of other
known cases of immunosupression
such as cancer or severe malnutrition
or other recognized etiologies.
• Weight loss (10% of body wt)
• Chronic diarrhoea
• Prolonged fever
• Persistent cough
• Generalized dermatitis
• Recurrent herpes zoster
• Oropharyngeal candidiasis
• Generalised lymphadenopathy
Enzyme Linked Immunosorbent
• Screening test for HIV
• Sensitivity > 99.9%
• Confirmatory test
• Specificity > 99.9% (when combined with ELIZA)
Absolute CD4 lymphocyte count
• Predictor of HIV progression
• Risk of opportunistic infections and AIDS when
HIV viral load tests
• Best test for diagnosis of acute HIV infection
• Correlates with disease progression and response
Urine Western Blot
◦ As sensitive as testing
◦ Safe way to screen for
◦ Can cause false
positives in certain
people at high risk for
◦ The only FDA approved
◦ As accurate as blood
◦ Draws blood-derived
fluids from the gum
◦ NOT A SALIVA TEST!
It is the only 100 % effective method
of not acquiring HIV/AIDS.
Refraining from sexual contact: oral,
anal, or vaginal.
Refraining from intravenous drug use
A mutually monogamous (only one sex
partner) relationship with a person who is
not infected with HIV
HIV testing before intercourse is necessary
to prove your partner is not infected
Use condoms (female or male) every time
you have sex.
Always use latex or polyurethane condom.
If a needle/syringe or cooker is
shared, it must be disinfected:
◦ Fill the syringe with undiluted bleach and
wait at least 30 seconds.
◦ thoroughly rinse with water
◦ Do this between each person’s use