This document summarizes the history and biology of HIV/AIDS. It discusses how HIV was isolated in 1983 and named in 1984/1986. It describes HIV's structure as a lentivirus with RNA genome and key enzymes. It outlines the viral genes and antigens involved in the core, envelope and replication. It also summarizes HIV's transmission routes, clinical stages, diagnosis process and current antiretroviral treatment approaches.

1. HIV
By
R.Parthasarathy

2. History of HIV/AIDS
In 1981
Kaposi’s sarcoma Pneumocystis carinii
pneumonia
In 1983
Luc Montagnier and Françoise Barré-Sinoussi
isolated retrovirus from lymphadenopathic patients.
Named it as lymphadenopathy associated virus (LAV).

3. History of HIV/AIDS
In 1984
Robert Gallo and colleagues, isolated and cultured
certain retrovirus.
Named it as human T cell lymphotrophic virus – III
or HTLV - III
In 1986
International Committee on Virus Nomenclature give a generic name
Human immunodeficiency virus (HIV)

4. Structure
Subgroup: lentivirus.
Lenti means slow (greek)
It is 32000 years old.
Family: Retroviridae.
Sperical enveloped virus. 90-120nm
2 identical +ve sense ssRNA,
Three enzymes
Reverse transcriptase (RT)
Protease (PR)
Integrase (IN)

5. Viral gens and antigen
Structural genes Functions
Determines the core and shell of the virus.
P55 (p15,p18,p24)
Gag
-p24 detected in the early stage of infection (before
antibodies)
Codes polymerase reverse transcriptase and protease
pol
P31,p51,p66
Determines the synthesis of envelope glycoprotein gp160
env - gp120 which forms the surface spike (72)
- gp 41 which forme transmembrane protein.
Non structural genes Functions
Tat (trans activating gene) Enchance all viral genes
Nef ( -ve factor gene) Regulates viral replication
Rev ( regulator of viral gene) Enchace the expression of structural protein
Vif (viral infectivity factor) Influence infectivity of viral particles.
Vpu and vpx (1&2) Enchance maturation and release of virus

6. Viral gens and antigen
Non structural genes Functions
vpr Stimulate promoter region
Contain sequence giving promoter, enhancer and
LTR sequence
integration signals.
Viral classification and subtypes
M – major
N – new
O – outlier
P – pending

8. Mode of transmission
Types of exposure Chance of infection per exposure(ApproX)
Blood and blood products >90%
Tissue and organ donation 50-90%
Sexual transmission 0.1 – 1.0%
Through injections and injuries 0.5 – 1.0%
Mother to fetal baby 30%

10. Clinical symptoms are classified as mentioned below:

12. Lab dignosis
Screening, measuring the antibodies to Hiv using
ELISA
Confirmed by western Blot
Treatment
1. Nucleoside and non nucleoside analogues
- inhibits reverse transcriptase enzyme.
Eg: Zidovudine (Azidothmidine, AZT), Didanosine,
Zalcitabine, lamivudine

13. Treatment
2. Protease inhibitors
- inhibits protease enzyme
Eg: sanquinavir, Ritonavir, indinavir
HAART(highly active antiretroviral therapy)
- combined therapy(Both)
- This method is currently used.

14. References
• Anathanarayan and paniker’s, Text book of
microbiology, 7th edition.
• Sherrai medical microbiology, 5th edition.
• Net sources
www.avert.com
www.cdc.gov
www.unaids.org