Mechanisms of Viral Infection and Pathogenesis

Question 1

PRIMARY INFECTION:
Where does VSV start?

How can Reactivation occur with viruses?

SECONDARY INFECTION:
What is it?

When can it occur?

Answer 1

• Respiratory tract with local replication and spread
• Virus penetrates skin and enters neurons, Migrates in the axon as uncoated capsids. Upon reactivation, the infectious virion is then produced, Migration back to skin.
• Infection with a second organism
• Can occur after an infection that compromises the immune system e.g. Infections in HIV patients

Question 2

What are the ways in which Viruses can evade the immune system?

Answer 2

• Perinatal infections
• Latency - After primary infection, it enters areas (e.g. dorsal root ganglion) and remains latent to evade detection
• Hinder Antigen presentation - e.g. Downregulating MHC I/II
• Hinder Antigen recognition - Changes viral proteins
• Replicate in privileged sites, like Leukocytes
• Release decoy particles to divert the immune response