Download AIDS(2020)

Human Immunodeficiency
Virus (HIV)
By: Dr .Mona Badr
As sistant Professor &
Consultant Virologist
College of Medicine & KKUH
Human Immunodeficiency Virus
 Retroviridae family is divided into three subfamilies:
 Oncovirinae includes human T-lymphotropic virus types 1 & 2

(HTLV-1
Adult T-cell leukemia
(HTLV-2
No human infection)
 Lentivirinae includes HIV 1
HIV2
 Spumavirinae
Worldwide AIDS (Pandemic)
West Africa AIDS
No human infection
Human Immunodeficiency Virus (Continued)
 HIV consists of an outer envelope covered with
glycoprotein spikes.
 An internal core genome consists of two identical ss-RNA
genome of which enzyme reverse transcriptase is bound.
 The viral genome has 3-structural genes termed
1. gag core protein, (p24)
2. Env (envelop glycoproteins) ,gp120,gp41.
3. Pol (Reverse Transcriptase,protease,integrase)
Structure of genetic Map of HIV
HIV replication cycle
Human Immunodeficiency Virus (Continued)
 HIV is known to infect mainly T-helper
cells(CD4),
macrophages
and
monocytes that have(CD4)proteins on
their surfaces.
 Destroying T-helper cells(CD4)lead to
severe
immunologic
impairment,
leading to multiple opportunistic
infections, unusual cancers and death.
Human Immunodeficiency Virus
Transmission:
1. Sexually:

By sexual contact with infected individual especially
homosexual

The virus is present in semens and vaginal secretions
2. Parenterally:

Direct exposure to infected blood and blood products.

Use contaminated needles and syringes as in (drug
abuser) and Tattooing.

Through contaminated surgical and dental instruments.

Sharing contaminated razors and tooth brushes,nail
cutters.
Human Immunodeficiency Virus
(Continued)
Transmission:
3. From mother to child

Infected mother transmit HIV to their babies
transplacentally(25%) ,but Treatment of the mother with
antiviral therapy(Zidovudine) during pregnancy can
reduce transmission in most cases.

Virus spread to child perinatally mainly (50%)during
delivery given (Nevirapine) as single dose during
delivery can reduce the transmission . breast feeding
also an important way of peri natal transmission (25%).
Virus Inactivation
 HIV is easily inactivated by treatment for 10 min at 37oC
with any of the following

10%
house hold bleach, Sodium Hypochlorite

50%
ethanol

35%
isopropanol

0.5%
Paraformaldehyde

0.3%
hydrogen peroxide
The Course of HIV-infection
 The course of HIV-infection can be
divided into three stages:
 The acute phase
 The chronic phase
1- A(PGL)
2-B(ARC)
 AIDS
The Course of HIV-infection
1. The acute phase
 Incubation period (1-4) weeks
 Mostly asymptomatic, in 25-50% of cases
patients may have symptoms resembling
infectious mononucleosis or influenza like
illness for short period& maculopapular rash.
 Characterized by normal no of CD4 and the
appearance of viral RNA in the blood (p24 )
core Ag followed by:

Appearance of two antibodies, one directed to the
envelope(Anti-gp120) and the other to the core
proteins(Anti-p24) start the chronic phase.
The Course of HIV-infection (Continued)
2. The chronic phase
totally asymptomatic

This phase
, which lasts
for about 1-10 years in adults, 1-5 years in children.

Characterized by the disappearance of HIV-Ag (p24)
from circulation and the presence of anti-envelope and anticore.

CD4 counts are generally within normal limits (usually
above 350 x106 cells/L)

At the end of this stage, two syndromes appear:

Persistent generalized lymph-adenopathy (PGL)

AIDS-related complex (ARC)
The Course of HIV-infection (Continued)
A. Persistent Generalized Lymphadenopathy:

Is present in 25-30% of patient who are otherwise
asymptomatic.

Enlarged lymph nodes (at least 1 cm in diameter), in two
or more extra-inguinal sites, persisting for at least 3-months
in the absence of any current illness or medication known to
cause enlarge lymph node.
Blood markers:

HIV Ag p24 (indicate active viral replication)

Anti-envelop (+ve) Anti-gp120.

Anti-core( –ve )Anti-p24 disappear from circulation.
CD4 count decrease but still more than 200 x106 cells/L
The Course of HIV-infection (Continued)
B. AIDS-related complex (ARC):
 Are indicative of a defect in cell-mediated immunity.
Characterized by candidacies (oral thrush) symptoms and signs
of AIDS, but lack the opportunistic infections as
Pneumocytosis OR tumors as Kaposi sarcoma.
 ARC Characterized by:

Fever, diarrhea persisting more than a month with weight
loss greater than 10% (Slim disease), night sweat, fatigue
and malaise

Neurological
neuropathy.
disease
as
myelopathy
and
peripheral
The Course of HIV-infection (Continued)
Blood markers:
 HIV Ag +ve p24 (indicate active viral replication)
 Anti-envelop +ve(Anti-gp120)
 Anti-core -ve (Anti-p24)
 CD4 count decreased but still more than
x106 cells/L
200
The Course of HIV-infection (Continued)
3. AIDS
 The end stage of the disease characterized by:

Marked decrease in CD4 T-helper cells < 200 x 106 cells/L

Severe immunologic impairment, cell mediated immunity

Opportunistic

Unusual cancers (
pneumocystis carinii
pneumonia, toxoplasmosis of brain, disseminated or
extra pulmonary myco-baceriosis etc.
infections
e.g.
Kaposi’s sarcoma)
Blood markers:

HIV Ag p24

Anti envelop +ve(Anti-gp120) , Anti-core –ve (Anti-p24)
Marked CD4 count less than 200 x106 cells/L
Slim disease
Kaposi’s sarcoma
Kaposi’s sarcoma
&
Slim disease
Kaposi’s sarcoma
Pneumocystis pneumonia
Laboratory Diagnosis
Screening
Elisa
HIV-antibody
Confirming
W.B.
Riba
HIV Ag p24
PCR
Laboratory Diagnosis

By detection of both HIV-Ab and HIV-Ag, using EISA
(screening test).

If results are negative, report negative.

If results are positive, repeat the screening test in
duplicate

Repeatedly reactive specimens, must be confirmed by
Western blot and HIV-Ag test by Eliza.

If the confirmatory results are negative, report negative

If the confirmatory test results are positive, report
positive
Laboratory Diagnosis (Continued)
Western Blot:

To confirm the presence of Anti –HIV to the structural
proteins of the virus
gag
core protein
by electrophoresis
env
pol
envelop protein
reverse transcreptase
HIV Ag p24: ( ELIZA)

To confirm the presence of the major protein of the core.
PCR:

For detection of HIV RNA in the blood plasma (viral
load) this test is important for HIV diagnosis in infant of
infected mother and also to monitor the antiviral
treatment
LABORATORY DIAGNOSIS
Indeterminate results:

Western blot indeterminate result, means that the test
specimen not positive nor negative.

The individual must be retested after 8-12 weeks.

If the result is negative, report negative

If the result is positive, report positive

If the individual still indeterminate then he or she must
be referred to medical evaluation

The aim of medical evaluation is to look for signs and
symptoms suggesting HIV-infection.

Or PCR to look for HIV-RNA genome.
Treatment
 Treatment does not eradicate the virus, but
suppress the HIV replication.
 Treatment, should continue for all life
 The aim of treatment is to maintain the immune
system of the patient near normal as possible
 At the present time the combined therapy is used
two reverse transcriptase inhibitors pulse one
protease inhibitor
Treatment (Continued)
A. Reverse Transcriptase Inhibitors:

AZT
Zidovudine

ddC
Zalcitabine

ddI
Didanosine

d4T
Stavudine

3TC
Lamivudine

All the above anti-viral drugs are nucleoside analogues.
B. Protease inhibitors

Saquinavir

Indiniavir

Ritonavir

Nelfinavir
Treatment (Continued)
Prevention & Control:
 There is no vaccine available yet for HIV

Practice safer sex by having one sexual partner

Do not share razors, tooth brushes, etc

Do not share needles and syringes

Avoid direct exposure to body fluids

Educate the public about HIV-infection.
THANK YOU
GOOD LUCK
 THANK
YOU