Flashcards in Hemorrhagic Fever Viruses Objectives/Big picture only Deck (20):
What are the flavivirdae viruses he discussed and what are their properties (transmission, enveloped, non enveloped, +/- RNA, DNA, segmented, etc)
Dengue and yellow fever
enveloped, non-segmented, + RNA
Describe the replication scheme of Flaviviridae viruses.
Dengue and yellow fever:
1. receptor mediated endocytosis with pH dependent uncoating.
2. host ribosome translates +RNA to make single polypeptide.
3. polypeptide is cleaved by viral and host proteases
4. cleavage results in RdRP that replicates genome (+ to - to many ++++)
5. + RNA used to make structural proteins
6. virions assembled and bud into ER and are released at cell surface
What are the Bunyaviridae viruses and what their properties?
enveloped, single strand, 2-3 segments, - RNA
Rift Valley fever (mosquitos infecting livestock and humans contact the animal blood or organs)
hemorrhagic fever with renal syndrome (rodents)
Describe the replication of the bunyaviridae viruses.
1. endocytosed and uncoat with low pH
2. - RNA is transcribed into + RNA by the RdNP packaged in the virion
3. + cRNA translated into structural proteins and used to make many -RNA copies
4. virions packaged and bud
What are the arenaviridae viruses and what are the properties?
Lassa Fever ("Old World") and South American Hemorrhagic fever ("New World")
transmitted by aerosolized rodent excreta
enveloped, segmented (2), ambisense RNA that contain host cell ribosome
Describe the replication of arenaviridae.
"non-conventianal ambisense strategy"
1. pH dept endocytosis
2. Tx of only the NP and L parts of the genome (similar -RNA to +cRNA) using packaged RdRP
3. Tx of full copy of 2 segments
4. +cRNA used for structural proteins and template for viral genomes
5. virions packaged and released at cell surface
What are the Filoviridae viruses and what are their properties?
Marburg and Ebola
transmitted by blood and fluids (contaminated needles and syringes)
enveloped, non-segmented, -RNA, and rod shaped
Describe the replication of filoviridae.
1. endocytosis trigged by low pH and proteolytic processing
2. -RNA to +cRNA by viral RdRP
3. synthesis of proteins and -RNA copies
4. assembly of virions and released by bidding at cell surface
What viruses can be transmitted human to human?
yellow fever, flioviruses (marburg and ebola)
What is the most effective treatment for these viruses?
*ribavirin has been shown to reduce severity of illnesses caused by arenaviruses (NOT ture for filovirus/ebola/marburg)
How can rift valley fever virus be controlled?
Do we have vaccinations for any of these viruses?
only yellow fever
Hepacivirus is what type of virus?
T/F: Treat classis dengue with NSAIDs
F ("do NOT")
What are possible hosts for the yellow fever virus?
humans or non-human primates
Can cause hemorrhagic hepatitis, encephalitis and retinal vasculitis (blindness)
Rift Valley (Bunyavirus)
What is considered the greatest risk factor for severe dengue hemorrhagic fever?
secondary inf with another serotype
(there are 4 serotypes, no overlapping immunity)
Can cause a mottled rash and metallic taste
Viruses associated with causing a cytokine storm: