M2-Flaviviridae & Togaviridae Flashcards
What group are the Flaviviridae viruses in?
Group 4–> (+)ssRNA
Are flaviviridae enveloped or non enveloped?
Enveloped
True or false: flaviviridae have helical capsids
False
-icosahedral
What are arboviruses?
Arthropod borne viruses
-Transmission through an arthropod
2 examples of arboviruses?
- West nile virus
- Yellow fever virus
What kind of arthropods spread arboviruses?
- Mosquitos
- Ticks
List the human pathogens in Flaviviridae family
- Hepatits C
- Dengue
- Yellow fever
- Zika
- West Nile
- Japanese encephalitis
- Tick-borne encephalitis virus
What 3 kind of human pathogen categories can Flaviviridae cause?
- Neurotropic
- Visceral
- Congenital
True or false: There is a clade of insect flavivivruses that have no known vertebrate host
True
Hepatitis C virus
-Bloodborne virus
-Flavivirus
-usually asymptomatic–>can develop into cancer
-IRES
-miRNA122
-no vaccine
What are the 2 forms of Dengue disease?
- Dengue Fever
- DHF/DSS
How can sequential infection with different dengue serotypes give rise to severe disease?
Primary infection–> get exposed to 1 type of dengue serotype you will have asymptomatic/mild infection/disease
Secondary infection–>exposed to different dengue serotype–> Anti-DENV recognizes new Dengue infection but can’t neutralize
What was the major problem with zika virus?
The virus can get into unborn fetus causing brain abnormalities
-can be sexually transmitted
Flaviviridae life cycle?
- Entry by endocytosis–>fusion
- Unpacking in the cytoplasm
- Replication and assembly on CELLULAR MEMBRANES–>viral proteins are translated on ER membrane
True or false: Immature virions are infectious
False
-Only mature virions are infectious–>to be mature pr cleavage needs to happen
What are 2 unique aspects of Hepatitis C virus at the 5’ end of genome
- IRES: Cap independent translation
- miRNA binding site provides stability to RNA
What does the liver have that other tissues do not have?
The liver has miRNA 122 expressed which makes viral RNA stable & functional allowing Hepatitis C to infect in liver
What are STAT proteins critical for?
IFN response and making ISG
What do Dengue and Zika virus target for degradation?
STAT2
What group are Togaviridae in?
Group 4 –> (+)ssRNA
Are Togaviridae enveloped or non enveloped?
Enveloped
What pathogens are in Togaviridae?
- Chikungunya–>Ades mosquito
- Equine encephalitis viruses
- Rubella
Why is Rubella concerning?
Can pass through placenta to fetus
Name a virus from the Flaviviridae and Togaviridae that can pass from the placenta to fetus?
Flaviviridae: Zika virus
Togaviridae: Rubella
What are TORCH pathogens?
Can cause birth defects
What does TORCH stand for?
Toxoplasma
Other (syphilis, Zika, parovirus)
Rubella
Cytomegalovirus (CMV)
Herpes
Why can we hope to eradicate rubella virus?
-Effective vaccination
-There are no animal vectors for this virus, only humans carry it–>we do not have to get rid of a whole species
True or false: Togaviridae and Flaviridae are both have polyproteins that are cut by proteases
True
What is 1 major difference between Togaviridae and Flaviridae when it comes to making mRNA
Togaviridae makes more than 1 mRNA
-non structural and structural (subgenomic RNA)
