Lecture 7 - HIV Pathogenesis - Virology

First Documented Cases (Early 1980s):
- Men with a rare form of cancer presenting lesions (Kaposi Sarcoma) around the neck, back, and mouth.
- Men suffering from Pneumocystis pneumonia, a serious lung infection caused by a fungus.
- Emergence of new diseases targeting immunocompromised populations.

AIDS stands for Acquired Immune Deficiency Syndrome.
Transmission routes include:
- Birth (from mother to child)
- Heterosexual contact
- Sharing needles (intravenous drug use)

Infection and Mortality Rates:
- New HIV infections every 12 seconds.
- Deaths from AIDS every 16 seconds.
- Approximately 39 million people currently living with HIV/AIDS globally.
- 30 million people have died from AIDS-related causes.
Comparative Scale: AIDS has impacted global populations more significantly than many wars.

Combined Antiretroviral Therapy: Used to manage and treat HIV.
- if you stop taking the meds then the virus will start propagating very fast
Distribution of Patients by Region (Total: 9.7 million receiving therapy):
- African Region: 7.53 million
- Region of the Americas: 308,000
- South-East Asia Region: 25,100
- European Region: 199,000
- Eastern Mediterranean Region: 938,000
- Western Pacific Region: 722,000
- High-income countries: 199,000

Renowned Canadian scientist (1945-2017) and past president of the International AIDS Society.
Promoted annual AIDS meeting in South Africa since 2000, significantly impacting global awareness and treatment progress.
diseases and perseverance of diseases often correlate with income

Enzyme that converts viral RNA into DNA, facilitating integration into host genomes.
Key Concepts:
- ssDNA cannot be transcribed.
- Cellular DNA polymerase is crucial for synthesizing double-stranded DNA.

Key proteins identified by molecular weight and glycosylation:
- SU (Surface Unit) as gp120: Viral receptor.
- TM (Transmembrane) as gp41: Fusion protein.
- CA (Capsid) as p24: Core structural protein.

Integration of double-stranded viral DNA into host genome, forming a pre-initiation complex (PIC).

Evidence of HIV dating back to 1959 from archived samples in Zaire (Central Africa).
High prevalence in urban sex workers in major cities of Zaire and Rwanda.

Based on sequence alignments, the major groups include:
- Group M: Major global form, highly prevalent.
- Group N and O: Potential transfer from animals to humans resulting in distinct strains.
Diversity in HIV-1: Multiple subtypes based on geographical prevalence.

Primary Source: Close resemblance of HIV-1 to SIV (Simian Immunodeficiency Virus) found in chimpanzees (SIV cpz).
Transmission dynamics:
- SIV primarily transmitted through sexual contact among infected chimps.
- Contact with SIV-positive monkeys likely facilitated cross-species transmission to humans.
origin of virus is central africa
SIV in chimps is excreted in feces
- chimps can’t swim
- This mode of transmission highlights the ecological factors that contributed to the emergence of HIV in human populations.
  - tend to concentrate in one area bcs they are in isolated areas
  - HIV = exogenous retrovirous… comes from a source
  - endogenous retroviruses translate through the germline

Transmission events linked to bushmeat hunting activities in the early 1920s, notably around Kinshasa, Zaire.
Factors influencing outbreaks:
- Urbanization during European colonization.
- Sex work as a transmission route.
- The introduction of modern healthcare in African regions.
Virus Characteristics:
- Conditions required for successful transmission appear limited due to inherent weaknesses of the virus under various environmental factors.

Understanding HIV pathogenesis is crucial for combating the epidemic, focusing on history, transmission, and current treatment strategies.