Lytic viruses Flashcards by Meghan May

Q

INitially during infection at the early stage, where is the viral concentration

A

LOW~~ the virus is naked and will begin to rapidly replicate

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Q

Picornavirus:
size
morphology
lipid envelope:
tegumnet:

A

22-30nm
icosahedral
\+ssRNA
NO envelope
NO tegument

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Q

pH of
enterovirus
rhinovirus
(both are picornavirus)

A

enterovirus = stable pH 3-9
Rhinorviurs = unstable below 6

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Q

Nucleac acid polartity of picornavirus

A

+ssRNA, Icosahedral

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Q

diseases associated with picornaviruses

Enterovirus

A

Paralysis, cold, neningitis, diarrhea, hand/foot mouth

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Q

diseases associated with picornaviruses

rhinovirus

A

common cold

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Q

diseases associated with picornaviruses

hepatovirus

A

hepatitis

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Q

diseases associated with picornaviruses

haprechovirus

A

GI, myocarditis, encehpalitis

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Q

diseases associated with picornaviruses

Kobovuris

A

Gastroenteritis

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Q

Capsid of enterovirus: resistant to mild sewage tx, salt water, detergents and temp changes… thus viruse can transmit via

A

fecal-oral routes, fomties and on hands:

see that it goes through sewage and landfills→ into water supply→ and to us

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Q

Even though picornavirus have many simular morphologies, they can have different

A

receptors on cell surface

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Q

Virus recovered from throat/stool

Asymptomatic

A

Inapparent (subclinical) 90-95% polio

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Q

Minor undifferntiated febrile illness

Influenza like or URI

A

Mild illness (4-8%) from polio

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Q

Minor illness progresses to CNS invasion

Stiff back and neck, lasts 2-10 days with rapid and complete recovery

A

Aseptic Meningitis (nonparalytic polio) 1-2%

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Q

Graymarrow inflammation, initially nonspecific febrile diseae w/ varialbe spectrum of paralysis; can see isolated msl groups or extensive paralysis

A

Paralytic poliomyletis

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Q

patterns of polio paralysis

A

Asymmetric flaccid paralysis, lower extremeties more affected, large msl grous often affected

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Q

Bulbar paralysis: i

A

involvement of CN’s—respiratory compromise and 5% death

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Q

recovery from parayltic poliomyletis

A

Slow recovery from this (2 years 100%) or residual paralysis

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Q

IG: the virus will go into the gut and intestine, stay there and

A

is shed in feces… only see complications

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Q

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 ________

A

viremia
(aseptic menigitis)
(paralytic poliomyletis)

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Q

Virus Isolation gotten from

A

Stool species, throat washings
CSF
Specifc, sensitive, time consuming

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Q

how do we commonly identify polio no

A

PCR

can so serology too,

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Q

General: ancient disease. Polio is exclusievely_____, fecal-oral transmission and enhanced by persons w/ sub-clinical infections seen during

A

human

Summer Epidemics d/t pool transmission

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Q

cause of early Endemic

A

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

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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

1. Virus released from BASAL surface 2. Excessive virus penton spike fibers released form cells disrupt cell adhehion jnx 3. Virus passes up to apical layer an shed into intestinal lumen 4. 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

1. Mature virion will attach to cell and loses its spikes→ goes in a penton 2. Penton releases→ Hexon with helical info 3. 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