Flashcards in Lytic Viruses Deck (30):
What is the size of the Picornavirus?
What is the morphology of the picornavirus?
nucleic acid of picornavirus
ssRNA, + polarity
Picornavirus: envelope or none?
Picornavirus: tegument or none?
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
Parechovirus: gastroenteritis, myocarditis, encephalitis
How are enteroviruses spread?
fecal oral, fomites, hands
What are the majority of polio infections like?
Inapparent infections (90-95%): virus found in throat or stool, but pt asymptomatic
The kinds of infections caused by polio
aseptic meningitis (nonparalytic polio)
Describe symptoms of paralytic poliomyelitis
asymmetric flaccid paralysis
lower extremities hit harder than upper
large muscle groups affected
how do you diagnose picornavirus
serology (neutralization, or 4 fold rise in titer to distinguish acute infection)
cell culture: time consuming
climate and time of year for epidemics of polio
What are the three major epidemiological phases of polio?
epidemic late 1800s and early 1900s
What is notable about the proteins synthesized from Picornavirus mRNA?
first a single polyprotein that is cleaved to several products
How does Poliovirus enter cells?
canyons bind to receptor on cell
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
How has polio fared in terms of control in the population?
well, with the inactivated and live attenuated virus vaccines
genome of adenovirus
double stranded DNA
adenovirus: envelope or none?
How is adenovirus spread?
What kinds of infections do adenovirus commonly cause?
unapparent respiratory infections
Shape of adenovirus capsid
Diseases by adenovirus
Is adenovirus more common in children or adults?
How does the tropism of adenovirus compare to that of picornavirus?
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
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
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
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