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Flashcards in Lytic Viruses Deck (30):
1

What is the size of the Picornavirus?

22-30 nm

2

What is the morphology of the picornavirus?

Icosahedral

3

nucleic acid of picornavirus

ssRNA, + polarity

4

Picornavirus: envelope or none?

none

5

Picornavirus: tegument or none?

none

6

What kinds of diseases are associated with Picornaviruses?

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

7

How are enteroviruses spread?

fecal oral, fomites, hands

8

What are the majority of polio infections like?

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

9

The kinds of infections caused by polio

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

10

Describe symptoms of paralytic poliomyelitis

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

11

how do you diagnose picornavirus

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

12

climate and time of year for epidemics of polio

temperate climate
summer

13

What are the three major epidemiological phases of polio?

endemic
epidemic late 1800s and early 1900s
post vaccine

14

What is notable about the proteins synthesized from Picornavirus mRNA?

first a single polyprotein that is cleaved to several products

15

How does Poliovirus enter cells?

canyons bind to receptor on cell

16

HOw do you prevent picornavirus infection?

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

17

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

well, with the inactivated and live attenuated virus vaccines

18

genome of adenovirus

double stranded DNA

19

adenovirus: envelope or none?

none

20

How is adenovirus spread?

fecal oral
respiratory

21

What kinds of infections do adenovirus commonly cause?

unapparent respiratory infections

22

Shape of adenovirus capsid

icosahedral

23

Diseases by adenovirus

gastrointestinal
respiratory
hepatitis
genitourinary
ocular
encephalitis
systemic

24

Is adenovirus more common in children or adults?

children

25

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

similar

26

How does adenovirus attach and enter cells?

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

27

Virus exit in adenovirus from cell

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

28

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

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

29

How does adnovirus gene expression work?

alternative splicing makes a lot of different polypeptides from each promoter

also, transcriptional program in which different genes are transcribed at different hour points

30

Is there a vaccine for Adenovirus?

Yes, although mostly limited to use by armed forces