rubella (seminar)
TRANSCRIPT
RubellaPresented By- Dr. KunalGuided By- Dr. Abhay Mudey
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HISTORY - RUBELLA Discovered in 18th century -
thought to be variant of measles The Teratogenic property of the
infection was documented by an Australian ophthalmologist Norman McAlister Gregg, in 1941
The virus was isolated in 1962
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Introduction From Latin meaning "little
red"
An attenuated vaccine was developed in 1967
First described as distinct clinical entity in German literature
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Rubella Virus
Togavirus
RNA virus
One antigenic type
Rapidly inactivated by chemical agents, low pH, heat and ultraviolet light
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EPIDEMIOLOGICAL DETERMINANTS
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Agent factor
s
Host factor
s
Environmental factors
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AGENT FACTORSA- Agent
Causative agent: Rubella virus ssRNA Virus of the Togaviridae Family genus Rubivirus One antigenic type Diameter 50 – 70 nm Enveloped Spherical Virus carry hemagglutinin
Virus multiply in the cytoplasm of infected cell. Highly sensitive to heat, extremes of pH & uv light. At 4°C, virus is relatively stable for 24 hours. 04/04/2015
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AGENT FACTORS cont.
B- Source of infection CASES
Subclinical Clinical
Congenital from infected pregnant women to fetus.
There is no known carrier state.
C- Period of communicability
It probably extends from a week before symptoms to about a week after rash appears.
Infectivity is greatest when the rash is erupting.
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HOST FACTORS
A- Age Disease of childhood
3-10 yrs age group. Following widespread
immunization campaigns persons older than 15 yrs account for 70% cases in developed countries.
B- Immunity One attack results in
life long immunity. Infants of immune
mothers are protected for 4-6 months.
In India, about 40% of child bearing age group women are susceptible to rubella.
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Immunity - Rubella Antibodies appear in
serum as rash fades and antibody titres raise
Rapid raise in 1 – 3 weeks
Rash in association with detection of IgM indicates recent infection.
IgG antibodies persist for life
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ENVIRONMENTAL FACTORS
Disease usually occurs in seasonal
pattern, during the late winter &
spring.
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Mode of Transmission
Person to person- via respiratory route:-
Droplet from nose & throat Droplet nuclei (aerosols) Maintain in human population by chain transmission.
Acquired during pregnancy- vertical transmission:- Virus can enter via the Placenta & infect the
foetus in utero (Congenital Rubella Syndrome).04/04/2015
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Incubation period
Between 14-21 days
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Rubella Pathogenesis
Respiratory transmission of virus [Spread by respiratory droplets]
Replication in nasopharynx and regional lymph nodes
Viremia 5-7 days after exposure with spread to tissues
Placenta and fetus infected during viremia
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Pathogenesis Continued……Rubella Virus Developed in the
nasopharynxRespirator
y Tract Skin Lymph Nodes Joints Placenta
or Fetus
• Cough• Minor
sore throat
• Rashes• Lesions
•Mild arthralgia• arthritis • Placentitis
• Fetal Damage
• Lymphadenopathy
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Rubella virusTransmitted
via respiratory
droplets
Infects cells in the upper respiratory
tract
Infects cells in the upper respiratory
tract
Virus multiplie
s
Extends in the regional lymph nodes
Virus replicates in the nasopharynx
Infection is established in the skin and other tissues including the respiratory tract
Pathophysiology
Forchheimer’s Spot may develop
Rashes develops, cough etc.
Virus can be found in the
skin, blood and respiratory
tract04/04/2015
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Vaccination and proper interventio
ns
Recent infection
With german measles vaccine
Virus culture/
blood test
Diagnosis: doctor suspects whether patient has measles
German Measles left untreated, it may
cause complications: Rubella Arthritis,
Encephalitis, Purpura bronchitis, abscesses
in the ears and pneumonia
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EPIDEMIOLOGY
Occurs worldwideThe virus tends to peak in countries with temperate climatesCommon in children ages 5-10 years oldHuman are only known reservoir.Host -3-10 yrsSource of infection – Respiratory secretionInfants with CRS may shed virus for a year or moreImmunity –life longOccurs round the year, peak in late winter and spring seasonTransmission – droplet, vertical transmissionI.P – 2-3 weeks average 18 daysRubella is world wide in distributionEpidemics occur every 4-9 years.
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Rubella Clinical Features
Incubation period 14 days (range 12-23 days)
Low grade fever
Lymphadenopathy in second week
Maculopapular rash 14-17 days after exposure
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SIGNS AND SYMPTOMS
RASH- After an incubation period of 14-
21 days, the primary symptom of rubella virus infection is
the appearance of a rash (exanthema) on the face
which spreads to the trunk and limbs and
usually fades after three days with no staining or peeling of the skin.
The skin manifestations are called "blueberry muffin lesions."
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SIGNS AND SYMPTOMS continued….
LYMPH NODE-
Tender lymphadenopathy (particularly posterior auricular and suboccipital lymph nodes)
persist for up to a week.
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SIGNS AND SYMPTOMS
TEMPERATURE-Fever rarely rises above 38o C (100.4 o F)04/04/2015
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Other manifestations & complications
May produce transient Arthritis, particular in women.
Serious complications are-Thrombocytopenia
PurpuraEncephalitis
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Pathognomonic Sign
Forchheimer’s Spot
Fleeting enanthemaPinpoint or larger petechiae that usually occur on the soft palate in 20% of patients Similar spots can be seen in measles and scarlet fever.
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Salt & Paper retinopathy
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Systemic events of Rubella Infection
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Main Clinical Events During Pregnancy
The clinical events occurring in the neonatal age is more important and divided into two major groups-
1 Congenital Rubella2 Post Natal Rubella
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Congenital Rubella Syndrome (crs)
Occurs during the first trimester of pregnancy.
Affects the development of the fetus. may lead to several birth defects. Infection may affect all organs. May lead to fetal death or premature
delivery. Severity of damage to fetus depends
gestational age. Infants: virus is isolated from urine
and feces.04/04/2015
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Rubella infection – At various trimesters
Ist trimester infections lead to abnormalities in 85 % of cases and greater damage to organs
2nd trimester infections lead to defects in 16 % > 20 weeks of pregnancy fetal defects are
uncommon However Rubella infection can also lead to fetal
deaths, and spontaneous abortion. The intrauterine infections lead to viral excretion in
various secretion in newborn up to 12-18 months.04/04/2015
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Rubella infection & Chance of CRS
0–28 days before conception - 43% chance
0–12 weeks after conception - 51% chance
13–26 weeks after conception - 23% chance
Infants are not generally affected if rubella is contracted during the third trimester
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Post natal Rubella
Occurs in Neonates and Childhood Adult infection occurs through mucosa of the
upper respiratory tract spread to cervical lymph nodes
Viremia develops after 7 – 9 day Lasts for 13 – 15 days Leads to development of antibodies The appearance of antibodies coincides the
appearance of suggestive immunologic basis for the rash
In 20 – 50 % cases of primary infections are subclinical. 04/04/2015
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Rubella Case Definition
Acute onset of generalized maculopapular rash and temperature of >37.2 C (>99 F), if measured with or without arthritis/arthralgia or lymphadenopathy or conjunctivitis.
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Clinical FeaturesRash at birthDeafnessCataractsHeart defectsMicrocephalyMental retardationBone alterationsLiver and spleen
damage 04/04/2015
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Cataract
Hearing
Defects
Sensoryneuronal deafnes
s
Classical Triad
Classical Triad of Rubella
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Other Abnormalities
Transient •low birth weight, hepatosplenomegaly, thrombocytopenic purpura,bone lesions, meningoencephalitis, hepatitis, haemolytic anemia, pneumonitis, lymphadenopathy
Permanent •Sensorineural deafness, Heart Defects (peripheral pulmonary stenosis,pulmonary valvular stenosis, patent ductus arteriosus,ventricular septal defect) Eye Defects (retinopathy, cataract, microopthalmia glaucoma, severe myopia) Other Defects (microcephaly, diabetes mellitis, thyroid disorders, dermatoglyptic abnormalities
Developmental •Sensorineural deafness, Mental retardation, Diabetes Mellitus, thyroid disorder
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Risks of rubella infection during pregnancy
Preconception minimal risk
0-12 weeks 100% risk of fetus being congenitally infected resulting in major congenital abnormalities.
Spontaneous abortion occurs in 20% of cases.
13-16 weeks Deafness & retinopathy 15% cases.
After 16 weeks Normal development, slight risk of deafness & retinopathy
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Diagnosis of Rubella in Adults
Clinical Diagnosis is unreliable Many viral infections mimic Rubella Specific diagnosis of infection with-
1 Isolation of virus 2 Evidence of seroconversion
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Isolation and Identification of virus
Nasopharyngeal or throat swabs taken 6 days prior or after appearance of rash is a good source of Rubella virus
Using cell cultured in shell vial antigens can be detected by Immunofluresecent methods
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Culturing the Virus
The virus can be cultured and adopted to continuous cell lines
Rabbit kidney cells (RK 13 ) and Vero cells
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Serology in Rubella
Haemagglutination inhibition test for Rubella is of Diagnostic significance
ELISA tests are greater importance A raised Antibody Titer must be demonstrated between two
serum samples taken at least 10 days apart. Detection of Rubella specific IgM in a single specimen.
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Diagnosis of acute rubella in mother
Fourfold rise in IgG titer between acute and convalescent serum specimensObtained within 7 to 10 days after onset of rashRepeated 2 to 3 weeks later
Presence of rubella specific IgM Positive rubella culture
Can be isolated from nasal, blood, throat, urine, or cerebrospinal fluid
Generally isolated from pharynx one week before to two weeks after rash.
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Diagnosis in infant Isolation of rubella virus Most frequently isolated from nasopharyngeal secretions Can be cultured from blood, urine, CSF, lens tissue, etc.
Serial rubella-specific IgG levels at 3, 6, and 12 months Rubella-specific IgG antibodies that persist at higher concentration or
longer duration than expected from passive transfer of maternal antibody
Maternal rubella antibody- half-life= 1 month, should decrease by 4 to 8 fold by 3 months of age and should disappear by 6 to 12 months
Can delay diagnosis
Presence of rubella-specific haemagglutination inhibition (HAI) after nine months of age
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Diagnosis in Infant continued……
Demonstration of rubella-specific IgM antibodies Demonstration of Rubella antibodies of IgM in a new born is
diagnostic value. As IgM group do not cross the placenta and they are produce in the infected fetus.
Most useful in infants younger than 2 months, but may persist for up to 12 months
False- negative-20% of infected infants tested for rubella IgM may not detectable titers before 1 month.
If clinically consistent and test negative after birth, should be retested at 1 month
False- positive- rheumatoid factor, viral infections (EBV, Infectious mononucleosis, parvovirus), and heterophile antibodies
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Medical Treatment Rubella is a mild self limited illness. No specific treatment or Antiviral treatment is indicated. Isolation and quarantine Increase fluid intake Encourage the patient to rest Good ventilation Encourage the patient to drink either lemon or orange juice Provide health teaching about Rubella (cause, immunizations)
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Treatment for acute maternal rubella
infection Acetaminophen for symptomatic relief IgG –
role is controversial, CDC recommends limiting use of immunoglobulin to women with known rubella exposure who decline pregnancy termination.
Glucocorticoids, platelet transfusion, and other supportive measures for complications.
Counseled about maternal-fetal transmission and offered pregnancy termination, especially prior to 16 weeks gestation.
After 20 weeks gestation- individualized management.04/04/2015
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Prevention
Rubella vaccine is given to children at 15 months of age as a part of the MMR (measles-mumps-rubella) immunization.
The vaccine is live and attenuated and confers lifelong immunity.
Given to children 12 and 15 months and again between 3-6 years of age
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Treatment, Prevention, Control
in childbearing age women No specific treatment is available
CRS can be prevented by effective immunization of the young children and teenage girls, remain the best option to prevent Congenital Rubella Syndrome.
The component of Rubella in MMR vaccine protects the vaccinated
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Vaccination of Women of Childbearing Age
Ask if pregnant or likely to become so in next 4 weeks
Exclude those who say "yes the vaccine has been already taken"
For others Explain theoretical risks Vaccinate 04/04/2015
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MMR Vaccine The MMR vaccine is a mixture of three
live attenuated viruses, administered via injection for immunization against measles, mumps and rubella virus strain RA 27/3 .
It is generally administered to children around the age of one year, with a second dose before starting school (i.e. age 4/5).
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MMR Vaccine The second dose is not a booster; it
is a dose to produce immunity in the small number of persons (2-5%) who fail to develop measles immunity after the first dose, the vaccine was licensed in 1963 and the second dose was introduced in the mid 1990s. It is widely used.
Contraindications= immunodeficiency disorder, history of anaphylaxis to neomycin, and pregnancy.
Side effects: arthritis, arthralgia, rash, adinopathy, or fever.
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Rubella VaccinesVaccine Trade Name
GMK-3:RK53 Cendevax
HPV-77:DK12 Rubelogen
HPV-77:DE5 Meruvax
RA 27/3* Meruvax II04/04/2015
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Rubella Vaccine Contined….
Composition Live virus (RA 27/3 strain)
Efficacy 95% (Range, 90%-97%)
Duration ofImmunity Lifelong
Schedule 1 Dose
Should be administered with measles and mumps as MMR 04/04/2015
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Rubella VaccineRecommendations for Increasing Coverage
Continued routine vaccination of children at age >12 months with vaccination required for school entry
Screen and vaccinate susceptible persons health care workers college entry prenatal with postpartum vaccination other health care visits workplace
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Rubella Vaccine (MMR) Indications
All infants >12 months of age
Susceptible adolescents and adults without documented evidence of rubella immunity
Emphasis on non-pregnant women of childbearing age, particularly those born outside the U.S.
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MMR Adverse Reactions
Fever Rash Joint symptoms Thrombocytopenia Parotitis Deafness Encephalopathy
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MMR VaccineContraindications and
Precautions
Severe allergic reaction to prior dose or vaccine component
Pregnancy Immunosuppression Moderate or severe acute illness Recent blood product
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Other Preventive Measures
Antenatal screening
All pregnant women attending antenatal clinics are tested for immune status against rubella.
Non-immune women are offered rubella vaccination in the immediate post partum period.
Since 1968, a highly effective live attenuated vaccine has been available with 95% efficacy
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Other Preventive Measures Continued….
Universal vaccination is now offered to all infants as a part of the MMR regimen in the USA, UK and a number of other countries.
Some countries such as the Czech Republic, Bangladesh, Malaysia & India continue to selectively vaccinate school girls before they reach childbearing age.
Both universal and selective vaccination policies will work provided that the coverage is high enough.
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Rubella Outbreak Control Guidelines
Laboratory diagnosis of rubella and CRS
Step-by-step guidelines on evaluation and management of outbreak
Rubella prevention and control among women of childbearing age
Rubella and CRS surveillance
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Recommendations
Do:-
Screening at first post-conceptual appointment, first-trimester screening
Don’t:-
Routine screening of child-bearing age women not recommended
Routine vaccination of all women of childbearing age not recommended 04/04/2015
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