M2-Flaviviridae & Togaviridae

Question 1

What group are the Flaviviridae viruses in?

Answer 1

Group 4–> (+)ssRNA

Question 2

Are flaviviridae enveloped or non enveloped?

Answer 2

Enveloped

Question 3

True or false: flaviviridae have helical capsids

Answer 3

False
-icosahedral

Question 4

What are arboviruses?

Answer 4

Arthropod borne viruses
-Transmission through an arthropod

Question 5

2 examples of arboviruses?

Answer 5

1. West nile virus
2. Yellow fever virus

Question 6

What kind of arthropods spread arboviruses?

Answer 6

1. Mosquitos
2. Ticks

Question 7

List the human pathogens in Flaviviridae family

Answer 7

1. Hepatits C
2. Dengue
3. Yellow fever
4. Zika
5. West Nile
6. Japanese encephalitis
7. Tick-borne encephalitis virus

Question 8

What 3 kind of human pathogen categories can Flaviviridae cause?

Answer 8

1. Neurotropic
2. Visceral
3. Congenital

Question 9

True or false: There is a clade of insect flavivivruses that have no known vertebrate host

Answer 9

True

Question 10

Hepatitis C virus

Answer 10

-Bloodborne virus
-Flavivirus
-usually asymptomatic–>can develop into cancer
-IRES
-miRNA122
-no vaccine

Question 11

What are the 2 forms of Dengue disease?

Answer 11

1. Dengue Fever
2. DHF/DSS

Question 12

How can sequential infection with different dengue serotypes give rise to severe disease?

Answer 12

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

Question 13

What was the major problem with zika virus?

Answer 13

The virus can get into unborn fetus causing brain abnormalities
-can be sexually transmitted

Question 14

Flaviviridae life cycle?

Answer 14

1. Entry by endocytosis–>fusion
2. Unpacking in the cytoplasm
3. Replication and assembly on CELLULAR MEMBRANES–>viral proteins are translated on ER membrane

Question 15

True or false: Immature virions are infectious

Answer 15

False
-Only mature virions are infectious–>to be mature pr cleavage needs to happen

Question 16

What are 2 unique aspects of Hepatitis C virus at the 5’ end of genome

Answer 16

1. IRES: Cap independent translation
2. miRNA binding site provides stability to RNA

Question 17

What does the liver have that other tissues do not have?

Answer 17

The liver has miRNA 122 expressed which makes viral RNA stable & functional allowing Hepatitis C to infect in liver

Question 18

What are STAT proteins critical for?

Answer 18

IFN response and making ISG

Question 19

What do Dengue and Zika virus target for degradation?

Answer 19

STAT2

Question 20

What group are Togaviridae in?

Answer 20

Group 4 –> (+)ssRNA

Question 21

Are Togaviridae enveloped or non enveloped?

Answer 21

Enveloped

Question 22

What pathogens are in Togaviridae?

Answer 22

1. Chikungunya–>Ades mosquito
2. Equine encephalitis viruses
3. Rubella

Question 23

Why is Rubella concerning?

Answer 23

Can pass through placenta to fetus

Question 24

Name a virus from the Flaviviridae and Togaviridae that can pass from the placenta to fetus?

Answer 24

Flaviviridae: Zika virus
Togaviridae: Rubella

Question 25

What are TORCH pathogens?

Answer 25

Can cause birth defects

Question 26

What does TORCH stand for?

Answer 26

Toxoplasma
Other (syphilis, Zika, parovirus)
Rubella
Cytomegalovirus (CMV)
Herpes

Question 27

Why can we hope to eradicate rubella virus?

Answer 27

-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

Question 28

True or false: Togaviridae and Flaviridae are both have polyproteins that are cut by proteases

Answer 28

True

Question 29

What is 1 major difference between Togaviridae and Flaviridae when it comes to making mRNA

Answer 29

Togaviridae makes more than 1 mRNA
-non structural and structural (subgenomic RNA)