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56 Cards in this Set
- Front
- Back
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What are the negative stranded RNAs?
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O Paul Rho ate five Buns:
orthomyxo paramyxo rhabdo arena filo bunyaviridae |
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Which negative RNa has an ambisense? circular DNA?
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Arenavirus and bunyavirus are circular with 3 segment ambisense
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Which neg RNA multiplies in the nucleus and cytoplasm?
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orthomyxovirus
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RNA structure of orthomyxovirus?
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OCTO (8 segments) linear segmented
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Two important glycoproteins on orthomyxo?
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HA and NA
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What is used to serotype viruses?
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NA and HA (H_N_ like H1N1)
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What is HA?
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it binds sialic acid on epithelial cells to promote fusion
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Why is HA called HA?
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it also hemagglutinates RBCs and elicits protective neutralizing Abs
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What is NA?
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it leaves sialic acid on mucins and prevents re-binding to a previously infected cell
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What transports the nucleocapsid out of the nucleus?
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M1 protein by binding to the membrane and initiating budding
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What causes M1 mediated nucleocapsid release?
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low pH
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What does M2 protein do?
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it forms a proton channel that allows H+ to cross the virion membrane to establish a low pH
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NA inhibitors would have what action?
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prevent cleavage of mucin, cause clumpage of exiting virions (NA prevents virions from aggregating)
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MOA of amantidine?
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Plugs the M2 channel to prevent low pH and subsequently the budding of M1 with plasma membrane which inhibits nucleocapsid release
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Where does orthomyxovirus synthesize mRNA?
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in the host nucleus with viral polymerase
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Where is orthomyxo +mRNA translated?
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in host cytoplasm, then processed through RER and Golgi before arriving at cell surface
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How is the host extracellular protease assential for infection?
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It cleaves HA which is required for membrane fusion function for budding of new virions
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Target cell for orthomyxo?
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ciliated epithelial cell; the barrier is mucus which is cleaved by NA
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How can one explain disease caused by orthomyxo?
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targeting and replication in repiratory epithelium causes cytopathology in resp tract and predisposition for secondary bacterial infections.
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Mutations in what causes influenza epidemics?
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mutations in the HA gene, causing antigenic drift
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What can cause pandemics of orthomyxo?
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Influenza A - antigenic shift due to reassortment of segments of genome ( because of trading RNA segments between species)
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Killed influenza vaccine:
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H1N1, H3N2, one B strain predicted by the WHO each year
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Amantadine works against what only?
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influenza A via blocking uncoating by plugging the M2 ion channel
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Neuraminidase inhibitors:
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Rulenza, Tamiflu
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Three major complications of influenza infections:
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1) secondary bacterial infections
2) Reye's syndrome 3) Guillain Barre |
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Reye's syndrome usually follow what infections?
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unfluenza B or varicella
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What is Guillain Barre?
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a very rare, acute polyneuritis after herpes, measles, influenze
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All paramyxoviruses have what glycoprotein?
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F or fusion glycoprotein which is required for infectivity and syncytia formation
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Measles glycoprotein
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HA only (HA! measly) that binds to CD46
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Parainfluenza glycoprotein?
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HA and NA combined into one callled HN "Para paired up"
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RSV glycoprotein?
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no activity of H or N
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Compare paramyxo with orthomyxo?
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paramyxo fusion happens at neutral pH, all replication takes in cytoplasm, genome is single strand.
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proteins on RSV?
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Fusion protein, no HA or NA
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Most important cause of respiratory problems in infants?
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RSV
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Treatment for RSV infected infants
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ribovirin
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Paramyxovirus that does not grow in cell culture that most children have by age 5
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Human metapneumovirus
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Croup, epidemic during fall? how many antigenic types?
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Parainfluenza virus with 4 antigenic types
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Glycoproteins on Parainfluenza virus?
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HN on one protein (paired para)
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Reye's syndrome is an immunological disease with high mortality following which viral infections?
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a week after Influenza B or Varicella (chicken pox)
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Guillain Barre occurs after which viral infections?
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Herpes, Measles (paramyxo) and Influenza (orthomyxo)
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Which Paramyxoviruses do not cause viremia?
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RSV, Parainfluenza, Human metapneumovirus
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Which paramyxoviruses do cause viremia?
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measles (HA only) and mumps (HN combined) from LUNG to BLOOD
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What is rubeola?
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The rash seen in measles af 10 days post exposure that lasts 5 days.
DO NOT CONFUSE WITH RUBELLA |
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What season does the puppy virus occur?
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Fall - parainfluenza - croup or barking cough in older kids; a paramyxovirus
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Diagnosis of the respiratory paramyxoviruses?
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RT-PCR
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Diagnosis of measles?
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serology and cell culture syncytia
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Presentation of measles?
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Me: CCC: coryza, cough, conjunctivis! with photophobia then koplick spots, then rash from head to toe
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Cell receptor for HA of measles?
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a complement control protein CD 46
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Complications of measles?
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giant cell pneumonia with superinfection, ecephalitis, and death.
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complication of measles immunization?
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Atypical measles infection with old killed vaccine
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Mumps gives you..
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bumps: parotitis, orchitis, pancreatitis
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transmission route of mumps
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aerosol to target organs to systemic!
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incubation period of mumps?
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16-18 days (age when you get lumps)
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complication of mumps in males?
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infertility
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Characteristics that mumps and measles have in common?
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viremic paramyxovirus with ONE SEROTYPE
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Glycoprotein on mumps virus?
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HN combined aaand F protein
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