Virus transmission

Viral Infection and Replication Cycle

• Key triggers for the viral life cycle include:

  • UV light

  • Temperature changes

  • Salt imbalance

General Viral Cycle

• All viruses have a common replication cycle:

  • Infection

  • Penetration

  • Integration

  • Production

  • Assembly

HIV Specifics

• HIV is an extensively studied virus and provides detailed insights into viral mechanisms.

Stages of HIV Cycle

• Infection Stage: Virus enters host cell.

• Entry/Integration Stage: The viral DNA integrates with host DNA using integrase.

• Production Stage: Viral components are synthesized.

• Assembly Stage: Components are assembled into new viruses.

Role of Antiviral Drugs

• AZT (Zidovudine):

  • Inhibits reverse transcriptase, preventing RNA from being converted to DNA.

• Integrase Strand Transfer Inhibitors (INSTIs):

  • Block integrase enzyme, stopping viral DNA from integrating into host DNA.

• Protease Inhibitors:

  • Prevent protease enzymes from assembling viral components, hindering replication.

Virus Transmission Methods

• Direct Contact:

  • Personal interaction that results in the exchange of bodily fluids (e.g., kissing, touching).

• Airborne Transmission:

  • Through respiratory droplets (coughing, sneezing).

• Vector Transmission:

  • Involves an intermediate host (e.g., mosquitoes, which carry viruses without being infected).

• Blood-to-Blood Contact:

  • Via contaminated needles or open wounds.

Key Points on Infection and Immune Response

• Exposure to viruses is common, but not all lead to illness due to immune defenses.

• The immune system's weakness (fatigue or poor health) can allow infections to take hold.

Conclusion

• Understanding the viral cycle and transmission methods is essential for managing viral infections effectively.