Download AIDS(2010 mona

Human Immunodeficiency
Virus (HIV)
By: Dr .Mona Badr
As sistant Professor &
Consultant Virologist
College of Medicine & KKUH
Human Immunodeficiency Virus
HIV
consists of an outer envelope covered with
glycoprotein spikes.
 An internal core genome consists of two identical
ss-RNA
transcriptase is bound.
genome of which enzyme reverse
Structure of genetic Map of HIV
Human Immunodeficiency Virus (Continued)
 HIV
is
known
to
infect
mainly
T-helper cells(CD4), macrophages.
 Destroying T-helper cells(CD4)lead to
severe
immunologic
impairment,
leading to multiple opportunistic
infections, unusual cancers and death.
 LATANCY
infection.
is known feature of HIV
Human Immunodeficiency Virus
Transmission:
1. Sexually:

By sexual contact with infected individual especially
homosexual

The virus is present in semen 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 &tooth brushes, nail cutters.
Human Immunodeficiency Virus
(Continued)
Transmission:
3. From mother to child

(VIRTICAL TRANSMITION) 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 prenatally mainly (50%)during
delivery given (Nevirapine) as single dose during
delivery can reduce the transmission . breast feeding
also an important way of 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.
 Characterized by normal no of CD4 and the
appearance of viral RNA in the blood ( core
Agp24) followed by appearance of two
antibodies Anti-envelop(Anti-gp120) &
 Anti- core(Anti-gp24).
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
(Anti-gp120) and anti-core(Anti-gp24).

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:

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)

CD4
Anti-envelop (+ve) Anti-gp120.&
but still more than 200 x106 cells/L
count decrease
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) and all 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)
 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 .
infections
e.g.
Kaposi’s sarcoma)
Blood markers:

HIV Ag p24

Anti envelop +ve(Anti-gp120) ,
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
HIV Ag p24
Confirming
W.B.
Riba
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 by ELECTROPHORESIS.
.
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
Human Immunodeficiency Virus

(VIRTICAL TRANSMITION) 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 prenatally mainly (50%)during
delivery given (Nevirapine) as single dose during
delivery can reduce the transmission . breast feeding
also an important way of transmission (25%).
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