Viral Pathogenesis Flashcards
what are main sites of viral entry?
- respiratory tract
- alimentary tract
- urinogenital tract
- conjunctiva (eyes)
- arthropod (insects)
- capillary
- skin
what is an overt disease?
Apparent disease (what we see, symptoms), many viruses are unapparent
what are acute virus infections?
- rapid onset of disease
- relatively brief period of symptoms
- resolution for infection happens within days
- localised to specific site of the body
what does widespread infection of virus to tissues cause?
viraemia
what are steps for infection for Influenza A virus?
- virus infects cell of respiratory tract
- destruction of respiratory epithelium occurs ( secondary bacterial infections)
- altered cytokine expression leading to fever (e.g. interleukin-1 and interferon)
what is antigenic drift?
gradual evolution of viruses to generate antigenic variants
what is antigenic shift?
significant changes in virus antigenic structure
what hosts play a huge role in generating new virus types through antigenic shift?
non-human hosts
what are 2 outcomes for a virus which enters the gut?
- virus excretion in the faeces
2. viraemia; in non-neuronal tissue or neuronal tissue which can lead to paralysis
what is a latent virus infection?
stays in tissues for the rest of your life but remains dormant until activated
what are 2 types of common latent virus infections?
- herpes simplex virus (cold sores type 1)
2. herpes simplex virus (genital lesion type 2)
what 3 types of stimuli can reactivate a latent virus?
- chemical signal
- mechanical signal
- light signal
what are some factors which suppress an immune system?
-stress
-drugs
-bacterial illness
-steroids
(all lower immune resistance)
where does virus lie dormant?
in the cell nucleus (but no replication occurs)
when does viral replication occur?
when virus migrates to epithelial cells (primary infection)
