Lecture on HIV

Introduction

• This lecture is focused on HIV.
• It builds on prior knowledge about viruses and their reproduction.

HIV Structure and Reproduction

• Key Components:
  • Protease: Cuts polypeptides into functional proteins.
  • Reverse Transcriptase: Converts viral RNA to viral DNA.
  • Integrase: Integrates viral DNA into the host cell DNA.
• Structure:
  • Capsid: Located inside, surrounded by matrix proteins.
  • Viral Envelope: Contains glycoproteins for attaching to host cells.
• Attachment and Infection:
  • Glycoproteins attach to CD4 receptors on helper T cells.
  • Membrane fusion leads to viral entry into the host cell.

HIV Reproduction Process

• Viral enzymes and RNA enter the host cell.
• Reverse Transcriptase:
  • Converts viral RNA to DNA.
  • Uses host cell nucleotides.
• Integrase:
  • Carries viral DNA into the nucleus.
  • Inserts DNA into host cell DNA.
• Host cell machinery produces viral proteins and new virions.
• Budding and Maturation:
  • New virions bud off, mature, and become infectious.

HIV as a Pandemic

• Defined as a worldwide epidemic.
• Primarily affects helper T cells, compromising the immune system.
• Can lead to AIDS if untreated.

Impact and Statistics

• HIV is the world's largest infectious killer.
• In 2019, estimated 38-44 million people living with HIV.
• Infections and deaths decreasing but still significant.
• High prevalence in sub-Saharan Africa; U.S. tied for seventh globally.

Transmission

• Transmitted through specific body fluids entering the bloodstream.
• Cannot be transmitted through casual contact or by insects.
• Higher transmission rates from men to women due to biological factors.

U.S. Statistics

• 1.1 million people with HIV; 1 in 7 unaware of their infection.
• Rising cases in the 25-34 age group due to unprotected sex and casual encounters.

Testing and Treatment

• Testing:
  • Easy, usually via cheek swab.
  • Tests for antibodies; early testing can miss infection.
• Prevention and Treatment:
  • PrEP: Pre-exposure prophylaxis for high-risk individuals.
  • PEP: Post-exposure prophylaxis for recent exposure (within 72 hours).
  • ART: Antiretroviral treatment targeting multiple stages of viral reproduction.

HIV Medications

• Multi-drug regimens have transformed HIV from a death sentence to a manageable condition.
• Inhibitors:
  • Entry and Fusion inhibitors to prevent cell entry.
  • Reverse Transcriptase inhibitors to block DNA formation.
  • Integrase and Protease inhibitors to prevent viral assembly and maturation.

Vaccine and Research

• No HIV vaccine yet.
• Ongoing research and lessons applied to other viruses like COVID-19.

Conclusion

• HIV remains a major global health issue.
• Importance of safety and prevention, especially for healthcare providers.
• Treatment and education are key to managing and reducing the impact of HIV.