Lytic viruses Flashcards
INitially during infection at the early stage, where is the viral concentration
LOW~~ the virus is naked and will begin to rapidly replicate
Picornavirus: size morphology lipid envelope: tegumnet:
22-30nm icosahedral \+ssRNA NO envelope NO tegument
pH of
enterovirus
rhinovirus
(both are picornavirus)
enterovirus = stable pH 3-9 Rhinorviurs = unstable below 6
Nucleac acid polartity of picornavirus
+ssRNA, Icosahedral
diseases associated with picornaviruses
Enterovirus
Paralysis, cold, neningitis, diarrhea, hand/foot mouth
diseases associated with picornaviruses
rhinovirus
common cold
diseases associated with picornaviruses
hepatovirus
hepatitis
diseases associated with picornaviruses
haprechovirus
GI, myocarditis, encehpalitis
diseases associated with picornaviruses
Kobovuris
Gastroenteritis
Capsid of enterovirus: resistant to mild sewage tx, salt water, detergents and temp changes… thus viruse can transmit via
fecal-oral routes, fomties and on hands:
see that it goes through sewage and landfills→ into water supply→ and to us
Even though picornavirus have many simular morphologies, they can have different
receptors on cell surface
Virus recovered from throat/stool
Asymptomatic
Inapparent (subclinical) 90-95% polio
Minor undifferntiated febrile illness
Influenza like or URI
Mild illness (4-8%) from polio
Minor illness progresses to CNS invasion
Stiff back and neck, lasts 2-10 days with rapid and complete recovery
Aseptic Meningitis (nonparalytic polio) 1-2%
Graymarrow inflammation, initially nonspecific febrile diseae w/ varialbe spectrum of paralysis; can see isolated msl groups or extensive paralysis
Paralytic poliomyletis
patterns of polio paralysis
Asymmetric flaccid paralysis, lower extremeties more affected, large msl grous often affected
Bulbar paralysis: i
involvement of CN’s—respiratory compromise and 5% death
recovery from parayltic poliomyletis
Slow recovery from this (2 years 100%) or residual paralysis
IG: the virus will go into the gut and intestine, stay there and
is shed in feces… only see complications
Polio can go → lymph nodes-→ enters blood stream and gets into liver and spleen causing______ (febrile illness) and can cross into CSF causesing _______or attack the gray matter causing ________
viremia
(aseptic menigitis)
(paralytic poliomyletis)
Virus Isolation gotten from
Stool species, throat washings
CSF
Specifc, sensitive, time consuming
how do we commonly identify polio no
PCR
can so serology too,
General: ancient disease. Polio is exclusievely_____, fecal-oral transmission and enhanced by persons w/ sub-clinical infections seen during
human
Summer Epidemics d/t pool transmission
cause of early Endemic
EARLY in history children encounter the virus at early age and were protected by mothers antibodies… high rate of subclincal infections with a low incidence of paralytic disease
Epidemic in early 1900 of polio
get indoor plumbing so pts are older when they first encounter virus and no longer have maternal antiBs. Higher incidence of paralytic diseae in older children/adults
Post-vaccine:
small number of cases and most all cases are vaccine related.
Picovirus interacts with receptors on cell surface→ this____ the capsid
weakens
Genome is_______ through the virion across the cell mmb OR virion is ______and genome is released
injected
endocytosed
Genome initially released from polio virus is used as mRNA for protein synthesis to make ______polyprotein
ONE
ONE polyprotein is cleaved to many little proteins including an
RNA-dependent RNA polymerase
RNA polymerase makes a ____strand template from the genome and replicates the genome with a protein _____covalently attached to the 5’ end
(-)
VPg
Structual prteons associate into the capsid, the genome is insereted and virions are releaed during
cell lysis
How does the piocornavirus enter
Entry: picovirus has a canyon structure on its surface… this is where the receptor binds from host cell so it can adhere
a. the canyon is an excellent target for antivirals
The virus must go: VPg———————-3 ‘ (+)RNA → 3’—————-VPg (–)RNA because
so it can make +sense copies
During proteolytic processing; the virus will ______translation of host cell and plays a role in cell death
inhibit
Why doesn’t the poliovirus genome go to the nucleus once it’s injected
The Genome can stay in the cytoplasm because it’s already a +RNA and doesn’t need to use host nucleus
Picornavirus prevention and control:
block virus attachment
virust entry and genome release
protease processing
RNA-dependent RNA polymerase inhibitors
Polio will Attach to _____Receptor in lung and spread to viremia if go into CNS get encephalitis and paralysis and if go through CSF get meningitis
CD55
Issues with the – sense RNA viruses
cannot translate their own and need to get to a +RNA thus need to bring along their own enZs to get it done; start to see they get bigger and bulkier
–can be non-segmtented or segmented genomes thus each segment transcribed sepearately
Negative strand RNA viruses
segmented genomes with each segment transcribed separate to produce monocistronic mRNAs
dsRNA (reovirus):
dsRNA (reovirus): segmented genomes with each segment transcribed separate to produce
monocistronic mRNAs
From adenoid tissues and and see latent virus there
Adenovirus
Adenovirus:
genome
enveloped?
dsDNA
NOT enveloped
adenovirus is spread:
fecal ora l and some respiratory
Disease associated with adenovirus
uapparent respiratory
Adenovirus apperance
isosahedral capsid with penton spikes
isosahedral capsid with penton spikes
Adenovirus
VERY complicated compared to piconavirus –needs own machinary and unique binding proteins
Adenovirus
Progression of disease with Adenovirus
Enter URT or GI then go to lymph nodes get viremia and then go systemic (disease of URT, conjuctivitis, GI, hemorrhagic cystitis (inflammation bladder) URT- go systemic and cause productive, persistent (lymph nodes), or latent infection
From URT, adenovirus
URT- go systemic and cause productive, persistent (lymph nodes), or latent infection
Viral lifecycle of adenovirus
Attach to DAF, migrate virus to clathirin pit, and then endocytosed or fused, shed into intestinal surface via penton spike fibers on capsule causing disruption adhesion juctions, enter nucleus using hexons, transcibe early and late genes which are spliced extensively
adenovirus will have interction with _____ and myosin as it surfs along
DAF
Adenovirus will engage with with receptor inthe carthrin coated pits
CAR receptor
What is the viral fusion protein for Adenovirus
PIV-3
The Adenovirus has introns and splicing events because
its a complex genome and thus you generate more proteins
Order of Production and release of adenovirus from epithelial cells
- Virus released from BASAL surface
- Excessive virus penton spike fibers released form cells disrupt cell adhehion jnx
- Virus passes up to apical layer an shed into intestinal lumen
- virus attaches to apical surface
splicing was first discovered in
adenoviruses
multiple spiced mRNAs and alternative splicing are used to make a variety of polypeptides from:
each promoter
Adenovirus intracellular production
- Mature virion will attach to cell and loses its spikes→ goes in a penton
- Penton releases→ Hexon with helical info
- Hexons deliver viral dna into the nucleus and use host nulcear stuff to take dna→ rna
Transcriptional program is a stepwise process with precise
timing of translation
Adenovirus vaccine is made and administered to
armed forces
