1. Fahareen-Binta-Mosharraf
RUBELLA
Fahareen-Binta-Mosharraf
MNS

2. Rubella is an infectious disease transmitted by the rubella virus.
The signs of the disease are: swelling of lymph nodes in the neck and a skin rash which first appears on the face and then rapidly spreads to other parts of the body
There is no drug therapy for rubella. However, the disease can be prevented by immunization.

3. What is Rubella? known as 3 day measles acute febrile illness
common childhood infection
also known as German measles because it was first described by German physicians, Friedrich Hoffmann, in mid-eighteenth century

4. What is Rubella? endemic throughout the world
comprehensive vaccination programs reduced the incidence of disease to low levels
infection during early pregnancy may result in serious abnormalities of fetus, including congenital malformations and mental retardation
What is Rubella?

5. Infectious Agent
family: Togaviridae (though not transmitted by arthropods)
genus: Rubivirus (Rubella Virus only member of the genus)
can be considered as paramyxovirus on epidemiologic basis (again classified as togavirus because of chemical & physical properties)

6. Infectious Agent enveloped; spherical diameter 50 – 70 nm
genome--> capped positive-sense RNA molecule of about 10 kb with a poly (A) tail
multiply in the cytoplasam of infected cell

7. Clinical Events Acute/ post natal rubella
Acquired (i.e. not congenital) rubella is transmitted via airborne droplet emission from the upper respiratory tract of active cases (can be passed along by the breath of people sick from Rubella).
Congenital rubella syndrome
Congenital rubella syndrome (CRS) can occur in a developing fetus of a pregnant woman who has contracted rubella during her first trimeste

8. Systemic Events of Rubella Infection

9. Post Natal Rubella: Clinical Findings
Malaise, low grade fever, morbilliform (measles like) rash
Rash not pathognomonic, rarely lasts more than 3 days
Posterior auricular & suboccipital lymphadenopathy
Transient arthralgia (pain in joint) & arthritis (inflammation of joint usually accompanied by pain, swelling, & changes in structure) in women
Complications (thrombocytopenic purpura & encephalitis) rare

10. Post Natal Rubella: Pathogenesis
usually mild and frequently subclinical
initial viral replication probably occurs in the respiratory tract, followed by multiplication in the cervical lymph nodes
viremia develops after 7–9 days; lasts until the appearance of antibody on about day 13–15
development of antibody coincides with the appearance of the rash, suggesting an immunologic basis for the rash
after the rash appears, virus remains detectable only in nasopharynx, may persist for several weeks

11. Post Natal Rubella: Natural History
IgG
IgM
Fig: natural history of primary rubella infection: virus production and Ab response

12. Post Natal Rubella: Immunity
much of initial Ab IgM (usually do not persist beyond 6 weeks after illness)
IgG generally persists for life
only one antigenic type of virus, so one attack of disease confers lifelong immunity

13. Post Natal Rubella: Prevention
attenuated live vaccine available as a single Ag or combined with measles & mumps vaccine (MMR)
vaccine induces lifelong immunity in at least 95% of recipients
vaccine safe & causes few side effects (children: mild fever, lymphadenopathy, fleeting rash; adults: arthralgia)
vaccine virus can cross placenta & infect fetus but not teratogenic (causing abnormal development of embryo)

14. Congenital Rubella

15. Congenital Rubella Syndrome
Congenital Rubella is teratogenic
As many as 10 to 15% of women in their childbearing years are susceptible to infection
CRS occurs in 25% or more of infants born to women who acquired rubella during the first trimester of pregnancy
Congenital Rubella Syndrome

16. Time Lines Prenatal: Trimester weeks Embryonic period – first 8 weeks
Fetal period – remaining 30 weeks
Postnatal: after birth
Neonatal: upto 28 days after birth
Trimester weeks
1st = 1-13
2nd =
3rd = 27 and on
(38-40)

17. Congenital Rubella: Clinical Findings
clinical features grouped into 3 broad categories:
Transient effects in infants
Permanent manifestations that may be apparent at birth or become recognized during the first year
Developmental abnormalities that appear & progress during childhood & adolescence

18. Congenital Rubella: Pathogenesis
maternal viremia associated with Rubella infection during early pregnancy may result in infection of placenta & fetus
serious abnormalities of fetus, including congenital malformations and mental retardation
limited number of fetal cells become infected, growth rate reduced, deranged & hypoplastic organ development, resulting in structural anomalies
earlier the infection in pregnancy, greater the damage done (birth defect uncommon if maternal infection after 18 th week of pregnancy)

19. Congenital Rubella: Pathogenesis
inapparent maternal infections can produce anomalies
may result in fetal death & spontaneous abortion
at birth, virus easily detectable in pharyngeal secretions, multiple organs, cerebrospinal fluid, urine & rectal swabs
virus excretion may last for 12 – 18 months after birth (level of shedding gradually decreases with age)

20. Congenital Rubella: Pathogenesis
Ist trimester infections lead to abnormalities in 85 % of cases & greater damage to organs
2nd trimester infections lead to defects in 16 % cases
> 20 weeks of pregnancy fetal defects are uncommon
rubella infection can also lead to fetal deaths, and spontaneous abortion
intrauterine infections lead to viral excretion in various secretion in newborn upto months

21. Congenital Rubella: Immunity
maternal rubella antibody in the form of IgG is transferred to infants and is gradually lost over a period of 6 months
presence of IgM indicates that synthesis by the infant in utero
children with congenital rubella exhibit impaired cell-mediated immunity specific for rubella virus

22. Congenital Rubella: Prevention
no specific treatment
can be prevented by childhood immunization with rubella vaccine to ensure that women of childbearing age are immune

23. Prevailing Genotypes of Rubella virus
Epidemiology
Prevailing Genotypes of Rubella virus
world wide in distribution
occurs round the year
epidemics occur every 20 – 25 years

24. Rubella Epidemiology Reservoir Human
Transmission Respiratory Subclinical cases may transmit
Temporal pattern Peak in late winter and spring
Communicability 7 days before to 5-7 days
after rash onset Infants with CRS may shed virus for a year or more