111/13/2015 Togaviruses

211/13/2015 Toga Viruses  Structure  Classification  Multiplication  Clinical manifestations  Epidemiology  Diagnosis  Control Baron’s Web Site Baron’s Web Site

311/13/2015 Togaviridiae  Rubivirus-rubella  Alphavirus- Equine Encephalitis, Sindbis  Pestivirus- animal pathogens ä bovine viral diarrhea, hog cholera

411/13/2015 Rubella German Measles (first diagnosed by German doctors) Three day Measles

511/13/2015 Rubella: Structure  enveloped  icosahedral  ss RNA sense  nm  30 nm core  hemaglutinin peplomers + ssRNA

611/13/2015 Rubella: Classification  Family Togaviridae  genus Rubivirus only member  single serotype  three structural polypeptides Unlike other Togaviruses rubella is not arthropod borne

711/13/2015 Rubella: Multiplication  RNA is capped and polyadenylated  serves as mRNA -> nonstructural proteins  sense RNA -> antisense RNA  Antisense RNA template for progeny RNA  antisense RNA--> mRNA -> structural proteins  mature at intracytoplasmic membranes

811/13/2015 Rubella: Clinical manifestations Postnatal  rash  lymphadenopathy  low grade fever Congenital  stillbirth  spontaneous abortion  birth defects

911/13/2015 Congential Rubella  Ocular-  Ocular- cataracts, retinitis, glucoma,microphthalmaia  Heart defects- patent ductus arteriosis  Deafness- cochelar deafness, central auditory imperception  CNS- mental retardation, encephalitis, microcephaly  Other- hepatitis, pneumonitis

1011/13/2015 Rubella: Pathogenesis  respiratory secretions -direct contact, droplet  multiplies in cells of respiratory system  extends to lymph nodes, spleen

1111/13/2015 Rubella: Epidemiology  worldwide  vaccines licenced 1969  no new epidemics  incidence ~ 100 /year Congential rubella occurs in unvaccinated susceptible young women

1211/13/2015 Rubella: Host defenses  interferon  cell mediate immunity  neutralizing antibodies  hemagglutinin inhibiting antibodies asymptomatic reinfection possible

1311/13/2015 Rubella: Diagnosis  Clinical manifestations- rash, lymphadenopathy  Isolate virus respiratory tract  Detect Rubella IgM

1411/13/2015 Diagnosis: Congenital Rubella  isolate virus - urine, CSF, blood  maternal circulating IgG- lasts 6 months  Detect fetal or neonate IgM

1511/13/2015 Rubella: Control  live attentuated rubella vaccine ä mumps-measles-rubella combination  subcutaneous  15 months of age  asymptomatic in children  mild symptoms in adults

1611/13/2015 Rubella: Control Strategies  10-20% young women not immunized  Therefore immunize ä college students ä health care personnel ä military personnel ä after childbirth, miscarriage or abortion USA data

1711/13/2015 Alphavirus EncephalitisSindbis

1811/13/2015 Alphaviruses are arthropod borne (arboviruses)

1911/13/2015 Alphavirus: Structure  icosahedral nm  enveloped  attachment glycoprotein  ss RNA, sense, monopartite

2011/13/2015 Alphavirus: Classification  common envelope glycoprotein  common capsid antigenic sites  26 antigenic types

2111/13/2015 Alphavirus: Multiplication  RNA is capped and polyadenylated  serves as mRNA -> nonstructural proteins  sense RNA -> antisense RNA  Antisense RNA template for progeny RNA  antisense RNA--> mRNA -> structural proteins  mature at intracytoplasmic membranes

2211/13/2015 Subgenomic mRNA  sense strand -> antisense strand  3’ one-third of antisense strand -> mRNA  mRNA -> structural proteins

2311/13/2015 Alphavirus: Clinical manifestations  Encephalitis viruses ä fever, malaise, headache and/or encephalitis  Arthritis viruses ä fever, rash, arthralgia, arthritis

2411/13/2015 Alphavirus: Epidemiology  mosquito-vertebrate-mosquito cycles  geographically restricted  epizootics- Venezuelan equine enchephalitis  urban epidemics- chikungunya virus  seasonal

2511/13/2015 Alphavirus: Diagnosis  clincal manifestations  known exposure  isolate virus  detect IgM

2611/13/2015 Alphavirus: Control  reduce mosquito populations  vaccinate vertebrate hosts- horses  vaccine humans at high risk of exposure