CNS Viruses -- Flaviviruses Flashcards
What is the structure of the flaviviridae?
Small, enveloped, nonsegmented, + strand RNA virus
What are the three flaviviruses you need to know?
St. Louis, West Nile, Japanese
How do flaviviruses enter a cell?
Receptor-mediated endocytosis
Is the nucleocapsid delivery of flaviviruses into the cytoplasm preceded by a pH-dependent fusion event?
Yes
What does the translated RNA genome of flaviviruses form? How does it differ from picornaviruses?
single polyprotein; contains 5’-cap
T/F – flaviviruses get their genomic RNA replicated by host polymerase
False – viral polymerase
How do flaviviruses get out of a cell?
Budding into ER or Golgi and enveloped virus released during transport at cell surface
Transmission of flaviviruses?
Insect vectors
Where do flaviviruses initially replicate?
Endothelial/epithelial cells of site of inoculation
What happens after flaviviruses establish initial replication?
Transient primary viremia –> replicate in macrophages, spleen or lymph nodes 3-7 days post exposure
Do flaviviruses progress beyond replication in RES?
No
What three clinical syndromes occur with St. Louis virus?
Febrile headache, aseptic meningitis, encephalitis
What’s the incubation of St. Louis?
4-21 days
Is there a vaccine or antiviral for St. Louis?
No – control with mosquito vector protection
What mosquito genus is involved with spread of West Nile? Are we the main host?
Culex; no – incidental, birds main
