Hemorrhagic Fever Viruses Objectives/Big picture only Flashcards Preview

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Flashcards in Hemorrhagic Fever Viruses Objectives/Big picture only Deck (20)
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1
Q

What are the flavivirdae viruses he discussed and what are their properties (transmission, enveloped, non enveloped, +/- RNA, DNA, segmented, etc)

A

Dengue and yellow fever

mosquitos

enveloped, non-segmented, + RNA

2
Q

Describe the replication scheme of Flaviviridae viruses.

A

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 ++++)
    • RNA used to make structural proteins
  5. virions assembled and bud into ER and are released at cell surface
3
Q

What are the Bunyaviridae viruses and what their properties?

A

enveloped, single strand, 2-3 segments, - RNA

Rift Valley fever (mosquitos infecting livestock and humans contact the animal blood or organs)
Crimean-Congo (ticks)
hemorrhagic fever with renal syndrome (rodents)

4
Q

Describe the replication of the bunyaviridae viruses.

A
  1. endocytosed and uncoat with low pH
    • RNA is transcribed into + RNA by the RdNP packaged in the virion
    • cRNA translated into structural proteins and used to make many -RNA copies
  2. virions packaged and bud
5
Q

What are the arenaviridae viruses and what are the properties?

A

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

6
Q

Describe the replication of arenaviridae.

A

“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
7
Q

What are the Filoviridae viruses and what are their properties?

A

Marburg and Ebola

transmitted by blood and fluids (contaminated needles and syringes)

enveloped, non-segmented, -RNA, and rod shaped

8
Q

Describe the replication of filoviridae.

A
  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
9
Q

What viruses can be transmitted human to human?

A

yellow fever, flioviruses (marburg and ebola)

10
Q

What is the most effective treatment for these viruses?

A

supportive care

*ribavirin has been shown to reduce severity of illnesses caused by arenaviruses (NOT ture for filovirus/ebola/marburg)

11
Q

How can rift valley fever virus be controlled?

A

immunizing livestock

12
Q

Do we have vaccinations for any of these viruses?

A

only yellow fever

13
Q

Hepacivirus is what type of virus?

A

flaviviridae

14
Q

T/F: Treat classis dengue with NSAIDs

A

F (“do NOT”)

15
Q

What are possible hosts for the yellow fever virus?

A

humans or non-human primates

16
Q

Can cause hemorrhagic hepatitis, encephalitis and retinal vasculitis (blindness)

A

Rift Valley (Bunyavirus)

17
Q

What is considered the greatest risk factor for severe dengue hemorrhagic fever?

A

secondary inf with another serotype

there are 4 serotypes, no overlapping immunity

18
Q

Can cause a mottled rash and metallic taste

A

classic dengue

19
Q

Viruses associated with causing a cytokine storm:

A

filovirus

20
Q

In a filovirus infection what a possible liver abnormality?

A

lesions containing filovirus nucleocapsid