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18 Cards in this Set
- Front
- Back
What are the different viruses covered in this lecture?
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1.) positive RNA: picornaviridae (non-enveloped and icosahedral)
2.) positive RNA: coronaviridae (helical and enveloped) 3.) positive RNA (non enveloped and icosahedral: caliciviriadae 4.) double stranded; non-enveloped: icosahedral: reoviridae |
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Why is there no need to make mRNA: for the positive sense RNA viruses?
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positive sense RNA genomes can go directly to proteins
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positive stranded RNA viruses: 4 general important points:
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1.) genome serves as mRNA and is infectious
2.) they are all non-segmented (note that the reovirus ds dna is segmented) 3.) virions do NOT contain any enzymes 4.) structure: enveloped or naked/ icosahedral or helical |
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What are the two main groups of picornaviruses and the subgroups of each of these groups?
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1.) rhinoviruses (103 serotypes)
2.) enteroviruses: PECU: poliovirus, echovirus, coxsackie viruses A and B, unknown enteroviruses |
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Describe the viral entry and receptor specificity for the picornaviruses? What are the surface cell receptors, in particular, that enterovirus binds to. (Hint: it is different for poliovirus vs. coxsackie virus and rhinovirus)
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-coxsackie virus and most rhinoviruses bind to ICAM-1
-poliovirus: binds to cell surface glycoprotein called CD155 (the poliovirus receptor) |
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What are four key points for enteroviruses?
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1.) major portal of entry is the mouth via ingestion of contaminated food or water; transmitted by the fecal-oral route
2.) stable at a low pH of the stomach; replicate in the GI tract and excreted in the stool 3.) stable at room temperature 4.) immunity is type-specific |
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Describe the pathogenesis of the enterovirus infection: The target tissue infected by the enterovirus determines the predominant disease caused by the virus.
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SKIN, MUSCLE, BRAIN, MENINGES:
enterovirus --> viral replication in oropharynx and intestine --> viral replication in lymphoid tissues --> viremia: SKIN: coxsackie virus A: hand food and mouth disease and herpangia MUSCLE: echovirus: coxsackieviruses A and B: --> Heart (myocarditis) and thorax (pleurodynia) BRAIN: poliovirus, coxsackieviruses A and B --> Paralytic disease and encephalitis MENINGES: echovirus, poliovirus, coxsackieviruses A and B --> meningitis |
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What are these pictures of?
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coxsackie A hand foot and mouth disease
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What are these pictures of?
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herpangina; coxsackie A
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Describe pathogenesis of poliovirus:
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-major portal of entry is the mouth via ingestion of contaminated food or water; transmitted by the fecal-oral route
-multiples in throat and intestinal tract and enters bloodstream AND spreads to the brain and the spinal cor -most infections are asymptomatic |
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What virus do these pictures relate to?
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poliovirus
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What are the two types of poliovaccines and list pros and cons to each!
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sabin: induces humoral
-risk of paralytic disease in recipients especially the immunocompromised Salk: +induces humoral immunity, no risk of disease in recipients, no shedding of virus, so no risk to contacts, no interference from wild-type non-polio enteroviruses -: no significant GI immunity and requires booster does AND more expensive |
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CORONAVIRUSES: (5 features)
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-enveloped and have a helical nucleocapsid
-largest positive strand RNA virus -second most common cause of the common cold -club shaped and petal shaped projections on the surface that form a corona or crown around the virus |
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VIRUS STRUCTURE: draw a sample virus structure of a coronavirus how many glycoproteins are there? and list them
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spike glycoprotein,
hemagluttinin-acetylesterase glycoprotein, membrane glycoprotein, small envelope glycoprotein |
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Calciviridae: features:
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-icosahedral and contain no envelope
-2 genera that contain human viruses: norovirus (norwalk) and sapovirus -viruses are resistant to environmental pressure, detergents, drying, and acid -transmission: via fecal-oral route -common cause of non-bacterial gastroenteritis (major cause of epidemics: 30-40%) |
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REOVIRUSES: What do they stand for and describe them:
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REO: respiratory, enteric, orphan
-double stranded RNA genome in 10-12 segments; -nonenveloped with double layered protein capsids each with icosahedral symmetry - |
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What does reovirus (rotovirus) cause and what are preventative measures?
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-most common cause of severe dehydrating diarrhea in infants and kids less than 3 years old
-control: consists of rigorous hygienic measures such as careful handwashing and adequate disposal of enteric excretions |
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What is the pathogenesis of the rheovirus:
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