Viral Diarrhea

Question 1

What is the most common cause of severe diarrhea in YOUNG CHILDREN worldwide?

Answer 1

Rotavirus

Question 2

What family is rotavirus in?

Answer 2

Reoviridae

Question 3

What protein is the outer capsid of rotavirus?

Answer 3

VP7 (major outer capside protein) and VP4 (spike)

Question 4

What protein is the inner capsid of rotavirus?

Answer 4

VP6

Question 5

Is rotavirus genome segmented or unsegmented?

Answer 5

Segmented

Allows rearrangement and different strains

Question 6

What is the function of VP7 and VP4?

Answer 6

Neutralization
Cleavage of VP7 by GI proteases initiates infection
VP4 also helps with binding

Question 7

What is the function of VP6?

Answer 7

Basis of immunoassays

Determines Group A, B, or C

Question 8

Which group of rotavirus is most common worldwide?

Answer 8

Group A

Question 9

What is speculated to be the cause of diarrhea associated with rotavirus?

Answer 9

NSP4 enterotoxin

Question 10

What is the most common serotype of rotavirus?

Answer 10

G1, P8

Question 11

How is NSP4 thought to cause diarrhea?

Answer 11

Induces fluid secretion

Induces actin rearrangement and paracellular leakage

Question 12

What is the mode of transmission of rotavirus?

Answer 12

Primarily: Fecal oral
Fomites
Common source (water or food)
Respiratory

Question 13

What are the symptoms of rotavirus?

Answer 13

Vomiting
Watery diarrhea (no blood or fecal leukocytes)
Low grade fever
(All typical for most viral gastroenteritis)

Question 14

What is the incubation period of rotavirus?

Answer 14

2 days

Question 15

How was the rotavirus vaccine made?

Answer 15

Takes monkey rotavirus but has human rotavirus surface antigens
Causes immune response but no pathogenesis

Question 16

Which serotypes of adenovirus that cause diarrhea?

Answer 16

Serotypes 40 and 41

Question 17

What is the structure of the enteric adenovirus virion?

Answer 17

dsDNA

Penton fibre projects from each apex

Question 18

What is the structure of astrovirus?

Answer 18

Small
ss (+) RNA
pointed star appearance

Question 19

What are the two major caliciviruses?

Answer 19

Norovirus and sapovirus

Question 20

What is the structure of rotavirus?

Answer 20

dsRNA

Wheel with spokes

Question 21

What is the structure of caliciviruses?

Answer 21

non-enveloped
(+) RNA
Cup (calix) - shaped surface depressions

Question 22

What is the most common viral agent of acute gastroenteritis outbreaks?

Answer 22

Norovirus

Question 23

What is the mode of transmission of caliciviruses?

Answer 23

Fecal-oral
Food and water
aerosol

Question 24

What is the seasonality of norovirus?

Answer 24

Winter peak

Question 25

What blood type is at increased risk of calicivirus infection?

Answer 25

Group O bloodtype

Question 26

Who is more susceptible to saporovirus and how do their symptoms manifest?

Answer 26

Young children

Diarrhea > vomiting

Question 27

Who is more susceptible to norovirus and how do their symptoms manifest?

Answer 27

Older children and adults

Vomiting > diarrhea

Question 28

How is rotavirus diagnosed?

Answer 28

Immunoassay for Group A rotavirus

Question 29

How is enteric adenovirus diagnosed?

Answer 29

Assays detect serotypes 40/41

Question 30

How is calicivirus diagnosed?

Answer 30

Electron microscopy
Serum antibody testing
RT-PCR

Question 31

How is astrovirus diagnosed?

Answer 31

Electron microscopy
Serum antibody testing
RT-PCR

Question 32

What is the treatment of viral diarrhea?

Answer 32

No antivirals
Supportive care (fluid, electrolytes, food)