Lytic Viruses

Question 1

What is the size of the Picornavirus?

Answer 1

22-30 nm

Question 2

What is the morphology of the picornavirus?

Answer 2

Icosahedral

Question 3

nucleic acid of picornavirus

Answer 3

ssRNA, + polarity

Question 4

Picornavirus: envelope or none?

Answer 4

none

Question 5

Picornavirus: tegument or none?

Answer 5

none

Question 6

What kinds of diseases are associated with Picornaviruses?

Answer 6

enteroviruses: paralysis (non polio and polio kind), common cold, meningitis, diarrhea, hand foot and mouth disease

Rhinoviruses: common cold

Hepatoviruses: hepatitis

Parechovirus: gastroenteritis, myocarditis, encephalitis

Kobuvirus: gastroenteritis

Question 7

How are enteroviruses spread?

Answer 7

fecal oral, fomites, hands

Question 8

What are the majority of polio infections like?

Answer 8

Inapparent infections (90-95%): virus found in throat or stool, but pt asymptomatic

Question 9

The kinds of infections caused by polio

Answer 9

inapparent (subclinical)
mild illness
aseptic meningitis (nonparalytic polio)
paralytic poliomyelitis

Question 10

Describe symptoms of paralytic poliomyelitis

Answer 10

asymmetric flaccid paralysis
lower extremities hit harder than upper
large muscle groups affected

Question 11

how do you diagnose picornavirus

Answer 11

PCR
serology (neutralization, or 4 fold rise in titer to distinguish acute infection)
cell culture: time consuming

Question 12

climate and time of year for epidemics of polio

Answer 12

temperate climate

summer

Question 13

What are the three major epidemiological phases of polio?

Answer 13

endemic
epidemic late 1800s and early 1900s
post vaccine

Question 14

What is notable about the proteins synthesized from Picornavirus mRNA?

Answer 14

first a single polyprotein that is cleaved to several products

Question 15

How does Poliovirus enter cells?

Answer 15

canyons bind to receptor on cell

Question 16

HOw do you prevent picornavirus infection?

Answer 16

block receptors (antibody to bind to canyon sites on Picornavirus)
block virus entry and genome release
interfere with protease processing
RNA-dependent RNA polymerase inhibitors

Question 17

How has polio fared in terms of control in the population?

Answer 17

well, with the inactivated and live attenuated virus vaccines

Question 18

genome of adenovirus

Answer 18

double stranded DNA

Question 19

adenovirus: envelope or none?

Answer 19

none

Question 20

How is adenovirus spread?

Answer 20

fecal oral

respiratory

Question 21

What kinds of infections do adenovirus commonly cause?

Answer 21

unapparent respiratory infections

Question 22

Shape of adenovirus capsid

Answer 22

icosahedral

Question 23

Diseases by adenovirus

Answer 23

gastrointestinal
respiratory
hepatitis
genitourinary
ocular
encephalitis
systemic

Question 24

Is adenovirus more common in children or adults?

Answer 24

children

Question 25

How does the tropism of adenovirus compare to that of picornavirus?

Answer 25

similar

Question 26

How does adenovirus attach and enter cells?

Answer 26

``` viral surfing on myosin finds receptor to interact with clathrin mediated endocytosis makes a membrane around itself fuses this membrane with the cell membrane ```

Question 27

Virus exit in adenovirus from cell

Answer 27

released from basal surface of epithelial cells in gut its penton spike fibers are released and disrupt the adhesion jxns between epithelial cells then virus flows between cells back into intestinal lumen

Question 28

How does processing of genetic material compare between adenovirus and picornavirus?

Answer 28

adenovirus goes into the nucleus and when transcribed into mNRA, gets processed b/c of introns. Picornavirus does not have introns--just synthesized into one polypeptide that is further cut

Question 29

How does adnovirus gene expression work?

Answer 29

alternative splicing makes a lot of different polypeptides from each promoter also, transcriptional program in which different genes are transcribed at different hour points

Question 30

Is there a vaccine for Adenovirus?

Answer 30

Yes, although mostly limited to use by armed forces