111/13/2015 togaviruses [email protected]
TRANSCRIPT
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Toga VirusesToga Viruses
StructureStructureClassificationClassificationMultiplicationMultiplicationClinical manifestationsClinical manifestationsEpidemiologyEpidemiologyDiagnosisDiagnosisControlControl
Baron’s Web Site
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TogaviridiaeTogaviridiae
Rubivirus-Rubivirus-rubellarubellaAlphavirus- Alphavirus- Equine Encephalitis, SindbisEquine Encephalitis, SindbisPestivirus- Pestivirus- animal pathogensanimal pathogens
bovine viral diarrhea, hog cholerabovine viral diarrhea, hog cholera
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RubellaRubella
German Measles
(first diagnosed by German doctors)
Three day Measles
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Rubella: StructureRubella: Structure
envelopedenvelopedicosahedral icosahedral ss RNA sensess RNA sense40-80 nm40-80 nm30 nm core30 nm core hemaglutinin peplomershemaglutinin peplomers
+ ssRNA+ ssRNA
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Rubella: ClassificationRubella: Classification
Family Family TogaviridaeTogaviridae genus genus RubivirusRubivirus only member only membersingle serotypesingle serotypethree structural polypeptidesthree structural polypeptides
Unlike other Unlike other Togaviruses rubella is Togaviruses rubella is notnot arthropod borne arthropod borne
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Rubella: MultiplicationRubella: Multiplication
RNA is capped and polyadenylatedRNA is capped and polyadenylated serves as mRNA -> nonstructural proteinsserves as mRNA -> nonstructural proteinssense RNA -> antisense RNAsense RNA -> antisense RNAAntisense RNA template for progeny RNAAntisense RNA template for progeny RNAantisense RNA--> mRNA -> structural antisense RNA--> mRNA -> structural
proteinsproteinsmature at intracytoplasmic membranesmature at intracytoplasmic membranes
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Rubella: Clinical manifestationsRubella: Clinical manifestations
PostnatalPostnatalrashrashlymphadenopathylymphadenopathylow grade feverlow grade fever
CongenitalCongenitalstillbirthstillbirthspontaneous abortionspontaneous abortionbirth defectsbirth defects
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Congential RubellaCongential Rubella
Ocular- Ocular- cataracts, retinitis, glucoma ,microphthalmaia
Heart defects- Heart defects- patent ductus arteriosispatent ductus arteriosisDeafness- Deafness- cochelar deafness, central cochelar deafness, central
auditory imperceptionauditory imperceptionCNS- CNS- mental retardation, encephalitis, mental retardation, encephalitis,
microcephalymicrocephalyOther-Other- hepatitis, pneumonitis hepatitis, pneumonitis
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Rubella: PathogenesisRubella: Pathogenesis
respiratory secretions -direct contact, respiratory secretions -direct contact, dropletdroplet
multiplies in cells of respiratory systemmultiplies in cells of respiratory systemextends to lymph nodes, spleenextends to lymph nodes, spleen
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Rubella: EpidemiologyRubella: Epidemiology
worldwideworldwidevaccines licenced 1969vaccines licenced 1969no new epidemicsno new epidemicsincidence ~ 100 /yearincidence ~ 100 /year
Congential rubella occurs in Congential rubella occurs in unvaccinated susceptible unvaccinated susceptible
young womenyoung women
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Rubella: Host defensesRubella: Host defenses
interferoninterferoncell mediate immunitycell mediate immunityneutralizing antibodiesneutralizing antibodieshemagglutinin inhibiting antibodieshemagglutinin inhibiting antibodies
asymptomatic reinfection possibleasymptomatic reinfection possible
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Rubella: DiagnosisRubella: Diagnosis
Clinical manifestations- rash, Clinical manifestations- rash, lymphadenopathylymphadenopathy
Isolate virus respiratory tractIsolate virus respiratory tractDetect Rubella IgMDetect Rubella IgM
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Diagnosis: Congenital RubellaDiagnosis: Congenital Rubella
isolate virus - urine, CSF, bloodisolate virus - urine, CSF, bloodmaternal circulating IgG- lasts 6 monthsmaternal circulating IgG- lasts 6 months Detect Detect fetal or neonate fetal or neonate IgMIgM
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Rubella: ControlRubella: Control
live attentuated rubella vaccinelive attentuated rubella vaccine mumps-measles-rubella combinationmumps-measles-rubella combination
subcutaneoussubcutaneous15 months of age15 months of ageasymptomatic in childrenasymptomatic in childrenmild symptoms in adultsmild symptoms in adults
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Rubella: Control StrategiesRubella: Control Strategies
10-20% young women not immunized10-20% young women not immunizedTherefore immunize Therefore immunize
college studentscollege studentshealth care personnelhealth care personnelmilitary personnelmilitary personnelafter childbirth, miscarriage or abortionafter childbirth, miscarriage or abortion
USA dataUSA data
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Alphavirus Alphavirus
EncephalitisEncephalitis
SindbisSindbis
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Alphaviruses are arthropod borne
(arboviruses)
Alphaviruses are arthropod borne
(arboviruses)
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Alphavirus: StructureAlphavirus: Structure
icosahedral 40-50 nmicosahedral 40-50 nmenvelopedenvelopedattachment glycoproteinattachment glycoproteinss RNA, sense, monopartitess RNA, sense, monopartite
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Alphavirus: ClassificationAlphavirus: Classification
common envelope glycoproteincommon envelope glycoproteincommon capsid antigenic sitescommon capsid antigenic sites26 antigenic types26 antigenic types
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Alphavirus: MultiplicationAlphavirus: Multiplication
RNA is capped and polyadenylatedRNA is capped and polyadenylated serves as mRNA -> nonstructural proteinsserves as mRNA -> nonstructural proteinssense RNA -> antisense RNAsense RNA -> antisense RNAAntisense RNA template for progeny RNAAntisense RNA template for progeny RNAantisense RNA--> mRNA -> structural antisense RNA--> mRNA -> structural
proteinsproteinsmature at intracytoplasmic membranesmature at intracytoplasmic membranes
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Subgenomic mRNA Subgenomic mRNA
sense strand -> antisense strandsense strand -> antisense strand3’ one-third of antisense strand -> mRNA3’ one-third of antisense strand -> mRNAmRNA -> structural proteinsmRNA -> structural proteins
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Alphavirus: Clinical manifestations
Alphavirus: Clinical manifestations
Encephalitis virusesEncephalitis viruses fever, malaise, headache and/or encephalitisfever, malaise, headache and/or encephalitis
Arthritis virusesArthritis viruses fever, rash, arthralgia, arthritisfever, rash, arthralgia, arthritis
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Alphavirus: EpidemiologyAlphavirus: Epidemiology
mosquito-vertebrate-mosquito cyclesmosquito-vertebrate-mosquito cyclesgeographically restrictedgeographically restrictedepizootics- Venezuelan equine epizootics- Venezuelan equine
enchephalitisenchephalitisurban epidemics- chikungunya virusurban epidemics- chikungunya virusseasonalseasonal
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Alphavirus: DiagnosisAlphavirus: Diagnosis
clincal manifestationsclincal manifestationsknown exposureknown exposureisolate virusisolate virusdetect IgMdetect IgM
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Alphavirus: ControlAlphavirus: Control
reduce mosquito populationsreduce mosquito populationsvaccinate vertebrate hosts- horsesvaccinate vertebrate hosts- horsesvaccine humans at high risk of exposurevaccine humans at high risk of exposure