Rubella Flashcards
rubella- other names and family name
German measles, 3 day measles
Matonaviridae
why was matonavridae separatedf rom toga
no vector for transmission
serologically distinct
serotypes and genotypes of rubell - can you get it again
1 serotype- so no severe reinfection
13 genotypes
genome of rubella
ssRNA positive
5’ non structural- replication and transcription
3’ structural- C (Capsid), E1,2 transmembrane glycoproteins
E1 is most important for attachment, fusion, neutralisation and haemagglutination
rubella in environment
unstable- inactivatec by lipid solvents, trypsin, uv
CPE in which cell line
very rare in most cell lines
in rabbit kidney cell line RK 13, BGMK (african green monkey kidney cell line)
6 childhood exanthems of children
MSR EP RiH
1st Measles
2nd Scarlet fever
3rd rubella
5th Erythema infectiosum (Parvo)
6th Roseola infantum (HHV6,7)
Epidemiology of rubella:
pre vaccine era- seropositivity comparison to measles; how often presents
attack rate compared to measles
how much needs to be seropositive for a place to be protected
places eliminted
adults- 80-90% - measles - 98%; every 6-9 years, small scale epidemics, every 30 years large scale epidemics, limited outbreaks in close settings like schools, military camps
SAR lesser than measles
> 90%
51% countries eliminated, us in 2004, north and south america in 2015
how is rubella spread
when max
how long infective
will congenital rubella be infective
will vaccinated be infective
droplet
onset of rash
10 days before to 15 days after rash
yes
no- they shed- but very low quantitites
can you get rubella twice or after vaccination
yes- but asymptomatic- only proven serologically
lifelong protection due to both cmi and humoral
reinfection 10 times more common in vaccinees than natural infection (that also HAI titre 64 or lesser)
chances of viremia (only local replciation in pharynx) and congenital rubella in preg very rare on reinfections
Natural course of Rubella
ip= 12 -23 days
1 week before that in blood viremia
1st fever rises… within few days, IgM and IgG starts rising - as that rises, viremia goes away, ln and rash starts- ln lasts weeks.. rash lasts 3-5 days.. fever rarely lasts beyond first day of rash
arthralgia- little late
cf of rubella- age
fetus- worst, child mild, adult- little more symptoms
child has no prodrome (even if fever present, very mild)- only symptoms- LN and rash
adults have prodrome, ln , rash and arthritis
splenomegaly
LN involved in rubella
rash in rubella and enanthem
suboccipital, postauricular, posterior cervical
maculopapular- immune mediated
begins on face- moves down body as rash fades from face
not confluent, can desquamtae, may also be absent
Forschheimer spot- petechial lesions on soft palate- not diagnstic
Complications of postnatal rubella
1) arthritis- 1/3rd- fingers, wrists, knee- last for almost month- immune complex mediated as well as virus replocation
2) hemorrhagic manifest due to thrombocyto and immune mediated vascular damage - more in children
3) encephalitis- more in adults
Congenital rubella syndrome- chance more in
symptoms
see notes
