dsRNA Viruses

Question 1

Which family was studied in the dsRNA virions?

Answer 1

Reoviridae

Question 2

Give a very brief description of reoviridae tissue tropism and transmission.

Answer 2

Broad host range and transmission via food, water, and arthropod vectors.

Question 3

What does the REO in Reoviridae stand for?

Answer 3

Respiratory Enteric Orphan Virus

Question 4

What kind of serotypes does Reovirus have?

Answer 4

T1L, T2J, and T3D

Question 5

Where does Reovirus replicate in host cells?

Answer 5

Inclusion bodies / Viral factories

Question 6

What BSL level do Reoviruses belong in? Why?

Answer 6

BSL1. They don’t cause diseases in humans

Question 7

What are the clinical trials of reovirus attempting to do?

Answer 7

Be used as an anti cancer agent because they seem to lyse cancer cells.

Question 8

How does reovirus help decrease cancer in a host?

Answer 8

It causes immunogenic cell death by killing cells directly and indirectly by lysis and by increasing activating cytokines respectively.

Question 9

Describe rotavirus

Answer 9

Rotavirus is a dsRNA virus which is the most common cause of severe diarrhea in infants and young children. Clinical presentation has changed from GI infection to plasma viremia

Question 10

How is rotavirus transmitted?

Answer 10

Via fecal-oral route.

Question 11

What is the primary infection of the rotavirus?

Answer 11

It infects the small intestine causing gastroenteritis and destroys gut cells causing malabsorption. Now it is also available systemically causing plasma viremia.

Question 12

Describe the physical structure of rotavirus

Answer 12

Has a triple capsid structure in 3 forms: virion, ISVP, and the core

Question 13

Describe the breakdown of the physical structure of rotavirus in the host

Answer 13

Virion undergoes proteolytic cleavage in GI tract or within endocytic vesicle
Infections subvirion particle
Delivery of transcriptionally active core to the plasma

Question 14

Describe rotavirus genome

Answer 14

11 segments of dsRNA of various lengths. 5’ polyphosphate cap on each strand to enhance viral RNA stability.

Question 15

Explain how the rotavirus genome could play a part in antigenic shift.

Answer 15

Rotavirus genome is segmented and therefore it could incorporate new/double/less in the developing capsids which could drastically change the function of the genome due to reassortment and lead to antigenic shift.

Question 16

How does rotavirus replicate?

Answer 16

Attachment via VP4 prot and clathrin mediated endocytosis
Loses outermost layer (VP4-7) in endosome
Early transcription in double layered particles
dsRNA never exposed to cytoplasm
Replication in viral factories
Late transcription in progeny cores
Double layered particles are coated with VP6 which bud across membrane through ER
Mature virions released during cell death

Question 17

What is copy choice recombination?

Answer 17

RdRp or RT switches from one RNA template to another during synthesis while still bound to the NA chain so there could be mixed ancestry.

Question 18

What kind of genomes favour template switching?

Answer 18

Intergenic and interprotein domains are usually immune because they have a secondary RNA structure that makes it more likely that template switching will be non-disruptive.