Togaviruses & Flaviviruses Flashcards
Structure
enveloped +ssRNA
Icosahedral capside
45-75 nm
Togaviruses
Alphaviruses (arthropod-spread encephalitis)
Rubivirus (rubella)
Flaviviruses
Alphaviruses (dengue, yellow fever, west nile, Zika, anthropod diseases.)
Hep C
pathogenesis
bite of an arthropod, e.g. mosquito. Lytic or persistent infections
FEMALE mosquitos. circulates in hosts plasma. infects endothelial cells of the capillaries + monocytes,macrophages dendritic cells
4 Phases + symptoms
Initial viremia - fever, chills, headaches, backaches, (flu-like) (most infections do not progress beyond here)
Secondary viremia - can infect target organs depending on tropism of virus
Brain infected - via endothilial cells lining vessels of brain
Hemorrhagic disease and shock - viral and immune cytolysis of infected vascular endothelial cells, + cytokine storm.
Immune response
IFN-a IFN-B
IgM for first week then IgG
immune response is important for resolution but exacerbates immunopathogenesis
Epidemiology
virus must stay wet, can be inactivated by drying,soap, detergents
Spread by arthropods
Control
Kill mosquitos
No treatments
Live attenuated vaccines
Diagnosis
RT-PCR for viral mRNA
monoclonal antibodies for distinguishing species/strains