Download Table II: Occupational health Management Strategy for Infectious

Human Immunodeficiency
Virus
By: Dr.Mona Badr
Assistant 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 ,
2. Env (envelop)
3. Pol (Reverse Transcriptase)
Structure of genetic Map of HIV
HIV replication cycle
Human Immunodeficiency Virus (Continued)
 HIV is known to infect mainly T-helper
cells and macrophages.
 Destroying T-helper cells results and
severe
immunologic
impairment,
leading to multiple opportunistic
infections, unusual cancers and death.
Human Immunodeficiency Virus
Transmission:
1. Sexually:

By sexual contact 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 and tooth brushes, nail
cutters.
Human Immunodeficiency Virus
(Continued)
Transmission:
3. From mother to child

Infected mother transmit HIV to their babies in
approximately 15-30% of cases. Treatment of the
mother with antiviral therapy can prevent this in
most cases.

HIV is transmitted from mother to child ,in utero,
during delivery or perinatally via breast feeding.
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
 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 the appearance of HIV-Ag in
the blood (p24 Ag core Ag) followed by:

Appearance of two antibodies, one directed to the
envelope and the other to the core proteins
The Course of HIV-infection (Continued)
2. The chronic phase

This phase totally asymptomatic, 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 anti-core.

CD4 counts are generally within normal limits (usually
above 350 x106 cells/L)

At the end of this stage, two syndromes appear:

Persistent generalized lymphadenopathy (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 non-contagious extra-inguinal sites, persisting for at
least 3-months in the absence of any other illness or
medication known to cause enlarge lymph node
Blood markers:

HIV Ag p24 (indicate active viral replication)

Anti-envelop +ve

Anti-core –ve

CD4 count but still >200 x106 cells/L
The Course of HIV-infection (Continued)
B. AIDS-related complex (ARC):
 Are indicative of a defect in cell-mediated immunity and
often manifested as candidiasis(oral thrush) seborrhoeic
dermatitis,and disseminated zoster (shingles).
 .constitutional symptoms;

Fever, diarrhea persisting more than a month with weight
loss greater than 10% (Slim disease), night sweat, fatigue
and malaise

Neurological disease as myelopathies and peripheral
neuropathy.
The Course of HIV-infection (Continued)
Blood markers:
 HIV Ag +ve( p24 indicate active viral replication)
 Anti-envelop +ve
 Anti-core -ve
 Decrease count of
200 x106 cells/L
CD4
but still more
than
The Course of HIV-infection (Continued)
Blood markers:
 HIV Ag +ve( p24 indicate active viral replication)
 Anti-envelop +ve
 Anti-core -ve
 Decrease count of
200 x106 cells/L
CD4
but still more
than
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 (Kaposi’s
pneumocystis carinii
pneumonia, toxoplasmosis of brain, disseminated or
extra pulmonary mycobaceriosis etc.
infections
e.g.
sarcoma)
Blood markers



HIV Ag +ve(
replication).
p24
.  Anti-envelop +ve
 Anti-envelop +ve
.
indicate
active
viral
Slim disease
Kaposi’s sarcoma
Kaposi’s sarcoma
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(twice)

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
env.
envelop Protein
pol
reverse transctpise
HIV Ag p24:

To confirm the presence of the major protein of the core.
PCR:

For detection of HIV RNA in the blood by using reverse
transcriptase.
Treatment
 Treatment does not eradicate the virus, but
suppress the HIV replication.
 Treatment, should continue all life
 The aim of treatment is to maintain the immune
system of the treated 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

Significant reduction in mother-to –child HIV
transmition if ZIDOVUDINE is given during pregnancy
OR NEVIRAPINE given as a single dose during
delivary.