lecture 10..............................pdf

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1. H.I.V. &AIIDS

2. WHAT IS HIV??
“Human Immunodeficiency Virus”
A unique type of virus (a retrovirus)
Invades the helper T cells (CD4 cells) in the body
of the host (defense mechanism of a person)
Threatening a global epidemic.
Preventable, manageable but not curable.

3. OTHER NAMES FOR HIV
Former names of the virus include:
Human T cell lymphotrophic virus (HTLV-III)
Lymphadenopathy-associated virus (LAV)
AIDS-associated retrovirus (ARV)

4. WHAT IS AIDS ???
“Acquired Immunodeficiency Syndrome”
HIV is the virus that causes AIDS
Disease limits the body’s ability to fight infection due
to markedly reduced helper T cells.
Patients have a very weak immune system (defense
mechanism)
Patients predisposed to multiple opportunistic
infections leading to death.

5. AIDS (definition)
Opportunistic infections and malignancies that rarely
occur in the absence of severe immunodeficiency
(eg, Pneumocystispneumonia, central nervous
system lymphoma).
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 have AIDS.

6. HIV
•Human Immunodeficiency Virus
•H= Infects only Human beings
•I = Immunodeficiency virus weakens
the immune system and increases the
risk of infection
•V= Virus that attacks the body

7. AIDS
•Acquired Immune Deficiency
Syndrome
•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

8. HIV and AIDS
•When the immune system
becomes weakened by HIV, the
illness progresses to AIDS
•Some blood tests, symptoms or
certain infections indicate
progression of HIV to AIDS

9. HIV-1 and HIV-2
••HIV-1 and HIV-2 are
•Transmitted through the same routes
•Associated with similar opportunistic
infections
▪•HIV-1 is more common worldwide
▪•HIV-2 is found in West Africa, Mozambique,
and Angola

10. HIV-1 and HIV-2
•HIV-2 is less easily transmitted
•HIV-2 is less pathogenic
•Duration of HIV-2 infection is shorter
•Mother To Children Transmission of HIV is
relatively rare with HIV-2

11. “THE VIRAL GENOME”
Icosahedral (20-sided), enveloped virus of the
lentivirus subfamily of retroviruses.
Retroviruses transcribe RNA to DNA.
Two viral strands of RNA
found in core surrounded by
protein outer coat.
Outer envelope contains a lipid
matrix within which specific viral
glycoproteins are imbedded.
These knob-like structures
responsible for binding to target
cell.

12. Modes of HIV/AIDS Transmission
◼Blood products
◼Semen
◼Vaginal fluids
◼Breast Milk
Through Bodily Fluids

13. IntraVenous Drug Abuse
Sharing Needles
Without sterilization Increases the chances of
contracting HIV
Unsterilized blades

14. Through sex (Unprotected )Intercourse
Oral
Anal
From mother to baby
Before Birth
During Birth

15. Transmission of HIV
HIV is not transmitted by
• Public baths
• Handshakes
• Work or school contact
• Using telephones
• Sharing cups, glasses,
plates, or other utensils
•Coughing, sneezing
•Insect bites
•Touching, hugging
•Water, food
•Kissing

16. NATURAL COURSE OF HIV/AIDS
Stage 1 - Primary
Short, flu-like illness -
occurs one to six
weeks after infection
 Mild symptoms
 Infected person can
infect other people

17. Stage 2 - Asymptomatic
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 low
levels
HIV antibodies are detectable in the blood

18. Stage 3 - Symptomatic
The immune system deteriorates
Opportunistic infections and cancers start to
appear.

19. Stage 4 - HIV  AIDS
The immune system
weakens too much as
CD4 cells decrease in
number.

20. Opportunistic Infections associated with AIDS
CD4<500
Bacterial infections
Tuberculosis (TB)
Herpes Simplex
Herpes Zoster
Vaginal candidiasis
Hairy leukoplakia
Kaposi’s sarcoma

21. Opportunistic Infections associated with AIDS
CD4<200
Pneumocystic carinii
Toxoplasmosis
Cryptococcosis
Coccidiodomycosis
Cryptosporiosis
Non hodgkin’s lymphoma

22. CD4 <50
Disseminated mycobacterium avium complex (MAC)
infection
Histoplasmosis
CMV retinitis
CNS lymphoma
Progressive multifocal leukoencephalopathy
HIV dementia

23. TB & HIV CO-INFECTION
TB is the most common opportunistic infection in HIV and
the first cause of mortality in HIV infected patients (10-30%)
10 million patients co-infected in the world.
Immunosuppression induced by HIV modifies the
clinical presentation of TB :
Subnormal clinical
High rate of treatment failure and relapse (5% vs < 1% in HIV)

24. Blood Detection Tests
HIV enzyme-linked
immunosorbent assay (ELISA)
Screening test for HIV
Sensitivity > 99.9%
Western blot Confirmatory test
Speicificity > 99.9% (when combined with
ELIZA)
HIV rapid antibody test Screening test for HIV
Simple to perform
Absolute CD4 lymphocyte count Predictor of HIV progression
Risk of opportunistic infections and AIDS when
<200
HIV viral load tests Best test for diagnosis of acute HIV infection
Correlates with disease progression and
response to HAART

25. Oral Testing
Orasure
The only FDA approved HIV
antibody.
As accurate as blood testing
Draws blood-derived fluids from
the gum tissue.
NOT A SALIVA TEST!

26. HAART = highly active anti-retroviral treatment

27. Antiretroviral Drugs (HAART)
Nucleoside Reverse Transcriptase inhibitors
AZT (Zidovudine)
Non-Nucleoside Transcriptase inhibitors
Viramune (Nevirapine)
Protease inhibitors
Norvir (Ritonavir)

28. PREVENTION:
Five ways to protect yourself?
Abstinence
Monogamous Relationship
Protected Sex
Sterile needles
New shaving/cutting blades