This document provides information about HIV/AIDS, including: - It defines endemic, epidemic, and pandemic, with AIDS classified as a pandemic. - As of 2003, it was estimated that 40 million people worldwide were living with HIV/AIDS, with 25-28.2 million in Sub-Saharan Africa. - HIV attacks and destroys CD4 cells, weakening the immune system and leaving the body vulnerable to opportunistic infections over time without treatment. - HIV is transmitted through direct contact with infected bodily fluids like blood, semen, vaginal fluids. It cannot be transmitted by casual contact. - Prevention strategies include blood screening, education on safer sex practices, STI treatment, and preventing mother

1. HIV / AIDS
-Malini Sundar Rajan
7th
semester BE Biotechnology
PESIT

2. 2
Endemic, Epidemic and Pandemic
– The Difference
 Endemic: a disease that exists permanently in a
particular region or population. Malaria is a
constant worry in parts of Africa.
 Epidemic: An outbreak of disease that attacks
many peoples at about the same time and may
spread through one or several communities.
 Pandemic: When an epidemic spreads
throughout the world. AIDS

3. 3
Scope of the HIV/AIDS Pandemic
00002-E-4 – 1 December 2003
Adults and children estimated to be livingAdults and children estimated to be living
with HIV/AIDS as of end 2003with HIV/AIDS as of end 2003
Total: 34 – 46 million
Western Europe
520 000520 000 –– 680 000680 000
North Africa & Middle East
470 000470 000 –– 730 000730 000
Sub-Saharan Africa
25.025.0 –– 28.2 million28.2 million
Eastern Europe
& Central Asia
1.21.2 –– 1.8 million1.8 million
South
& South-East Asia
4.64.6 –– 8.2 million8.2 million
Australia
& New Zealand
12 00012 000 –– 18 00018 000
North America
790 000790 000 –– 1.2 million1.2 million
Caribbean
350 000350 000 –– 590 000590 000
Latin America
1.31.3 –– 1.9 million1.9 million
East Asia & Pacific
700 000700 000 –– 1.3 million1.3 million

4. 4
Global HIV/AIDS in 2003
 40 million people are living with
HIV/AIDS.
 2.5 million are children under 15
years.
 14,000 new infections each day

5. 5
Impact of Global HIV
Negative economic impact on countries
Overwhelmed healthcare systems
Decreasing life expectancy
Deteriorating child survival rates
Increasing numbers of orphans

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HIV and AIDS
Human Immunodeficiency Virus
H = Human
I = Immunodeficiency
V = Virus

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HIV
 Retrovirus, enveloped ssRNA, RT (RNA
dependent DNA polymerase).
 Lentiviruses (HIV1 and 2),
and Oncoviruses (HTLVI, HTLVII).
 Fastidius, requires intimate contact.
 Attacks CD4 + cells.

8. 8

9. 9
HIV life cycle

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HIV and AIDS
Acquired ImmunoDeficiency Syndrome
A = not inherited
I = immune system
D =
deficiency – inability to protect against
illness
S =
syndrome, a group of symptoms or
illnesses that occur as a result of HIV
infection

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

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

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HIV-1 and HIV-2
Differences between HIV-1 and
HIV-2
 HIV-2 is less easily transmitted.
 HIV-2 develops more slowly.
 MTCT is relatively rare with HIV-2.

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Variation in HIV-1
 Most error-prone reverse transcriptase.
 Variability of the gp 120 antigen.
 Failure of the immune system to control the
infection.

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Natural History of HIV Infection

16. 16
Natural History of HIV Infection
HIV can be transmitted during each stage
 Seroconversion
 Infection with HIV, antibodies develop
 Asymptomatic
 No signs of HIV, immune system controls
virus production
 Symptomatic
 Physical signs of HIV infection, some
immune suppression
 AIDS
 Opportunistic infections, end-stage disease

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Natural History of HIV
Infection
 Severity of illness is
determined by amount
of virus in the body
(increasing viral load)
and the degree of
immune suppression
(decreasing CD4 count).
 Higher the viral load, the
sooner immune
suppression occurs.

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Natural History of HIV Infection
Immune suppression
 HIV attacks white blood cells, called
CD4 cells, that protect body from
illness.
 Over time, the body’s ability to fight
common infections is lost.
 Opportunistic infections occur.

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Natural History of HIV Infection
Direct infection of organ systems
Brain (HIV dementia)
Gut (wasting)
Heart (cardiomyopathy)

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_______________Head_________________
_
Toxoplasmosis (Toxo)
Cryptococcal meningitis
_______________Eyes__________________
Cytomegalovirus (CMV)
___________Mouth and Throat__________
Candidiasis (Yeast)
________________Lungs_______________
_
Pneumocystis carinii pneumonia (PCP)
Tuberculosis (TB)
Histoplasmosis
_________________Gut_________________
Cytomegalovirus (CMV)
Cryptosporidiosis
Mycobacterium avium complex (MAC)
________________Skin_________________
Herpes simplex
Shingles
_______________Genitals______________
Genital herpes
Human papillomavirus (HPV)
Vaginal candidiasis (Yeast)
HIV-Related Opportunistic
Infections

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Progression of HIV Infection
 HIGH viral load (number of copies of HIV in the
blood)
 LOW CD4 count (type of white blood cell)
 Increasing clinical symptoms (such as
opportunistic infections)

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Natural History of HIV
Infection-Summary
 HIV multiplies inside the CD4 cells, destroying them.
 As CD4 cell count decreases and viral load increases, the
immune defences are weakened.
 People infected with HIV become vulnerable to opportunistic
infections.
 HIV is a chronic viral infection with no known cure.
 Without ARV treatment, HIV progresses to symptomatic
disease and AIDS.

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Transmission of HIV
HIV is transmitted by
 Direct contact with infected blood
 Sexual contact: oral, anal or vaginal
 Direct contact with semen or vaginal and
cervical secretions
 Mothers infected with HIV to infants during
pregnancy, delivery and breastfeeding

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 Coughing,
sneezing
 Insect bites
 Touching, hugging
 Water, food
 Kissing
 Public baths/pools
Transmission of HIV
HIV cannot be transmitted by:
 Toilets
 Handshakes
 Work or school contact
 Telephones
 Cups, glasses,
plates, or other utensils

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Prevention of HIV Transmission
Public health strategies to prevent HIV transmission
 Screen all blood and blood products.
 Follow universal precautions.
 Educate in safer sex practises.
 Identify and treat STIs.
 Provide referral for treatment of drug
dependence.
 Apply the comprehensive PMTCT approach to
prevent perinatal transmission of HIV.

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Antiretroviral Therapy
A. Nucleoside Reverse Transcriptase Inhibitors
1. Zidovudine (AZT, ZDV)
2. ddI (didanosine)
3. ddC (zalcitabine)
4. d4T (stavudine)
5. 3TC (lamivudine)
B. Non-nucleoside Reverse Transcriptase Inhibitors
1. Nevirapine
2. Delavirdine
C. Protease Inhibitors (PI's)
1. Indinavir (Crixivan)
2. Ritonavir (Norvir)
3. Nelfinavir mesylate (Viracept)
4. Saquinavir (Invirase)

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References
 Introduction to Microbiology – A Case-
History Approach, by Ingraham and
Ingraham
 PMTCT Generic Training Package Module
1, from WHO website.
 http://aids.about.com/

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Thank You