RUBELLA Single-stranded, enveloper RNA virus of the genus Rubivirus Family Togaviridae Disease caused: German measles Benign, self-limiting Infects children, young unvaccinated adults Incubation period: 12-23 days Mode of Transmission Direct contact with respiratory droplets Transplacental Viral Replication Site: Upper Respiratory Tract Cervical lymph nodes Sign & Symptoms: Erythematous maculopapular rash Initially appears on the face Spreads to the trunk and extermities Disappear in 3-5 days Adolescents and Adults: Asymptomatic Low grade fever, malaise, swollen gland, Upper Respiratory Infection for 1-5 days
Other Clinical Manifestation: Encephalitis, thrombocytopenia with hemorrhage, neuritis Infection during pregnancy: May lead to: Miscarriage, stillbirth Congenital rubella syndrome (CRS) Deafness, eye defects (cataracts, glaucoma) Cardiac abnormalities Mental retardation, motor disabilities Congenital Malformations/Deformities Rubella Vaccine Live, attenuated rubella virus Mandatory immunization in infants and children Given in combination with other vaccines for measles, mumps and varicella: MMR Vaccine “measles/mumps/rubella vaccine” MMRV Vaccine “measles/mumps/rubella/varicella Laboratory Diagnosis
Viral Culture: slow growth Serologic Tests: preferred method of diagnosis Hemagglutination Inhibition (HI) Passive Hemagglutination Latex Agglutination Immunoassays Chemiluminiscence ELISA: most commonly used: Solid phase Capture ELISA: detects IgM Rubella antibodies IgM and IgG rubella antibodies elevate as the rashes (of German measles) begin to disappear IgM declines in 4-5 weeks (but may persist in low levels for a year) IgG rubella antibodies: marker of lifelong immunity Vaccination Natural exposure Lab Diagnosis for Congenital Rubella Infection Test mother’s serumfor the presence of rubella antibodies
Test fetal blood, cord blood, neonatal serum: rubella-specific IgM Positive lgm results confirmatory test: Viral Culture, RT-PCR -Clinical Immunology & Serology, 3rd edition Stevens page 383-384 Rubella (German measles) is highly communicable and produces mild fever and a transient rash in children and adults. All infections are viremic, and transplacental spread during the first trimester produces devastating teratogenic cardiac, ocular, and brain malformations (schluter, 1998).
Rubella is no longer endemic in United States because of widespread vaccination; genome analysis demonstrates that most ecent rubella cases are imported from Latin America. Routine prenatal screening for maternal rubella IgG as proof of immunity is standard practice. Only four cases of congenital have been identified since 2001, three of which occurred in immigrant mothers (MMWR, 2005). When acute rubella is suspected in a pregnant woman, the most straight forward diagnostic method assay of maternal serum for rubella IgM by EIA or IFA. Culture of rubella is technically complex and is not routinely available.
RT- PCR for rubella virus RNA performed on amniotic fluid is almost 100% sensitive and pecific and can also be performed on placenta and autopsy tissues (Revello, 1997; Mace, 2004). Multiple assays that can detect genomic material from rubella and from several agents of perinatal infection have been developed (McIver, 2005). The congenitally infected newborn is IgM positive and excreted rubella in urine for months to years. -Henrys clinical diagnosis and management by laboratory methods. 22nd edition. page 1052 Rubella virus infection during early pregnancy can lead to severe birth defects known as congenital rubella syndrome.
Sequelae of rubella virus infection include three istinct neurologic syndromes, as follows: Postinfectious encephalitis after acute infection. Neurologic manifestations after congenital infection. Rare neurodegenerative disorder, progressive rubella panencephalitis that can follow either congenital or postnatal infection. Serological Diagnosis of Viral Disease : Rubella Rubella (German measles) is normally insignificant except in pregnant women. This disease may cause a miscarriage, or it may cause a congenital heart disease, cataracts, deafness, and brain damage in the fetus.
Therefore it is extremely important to determine whether women who may become pregnant have immunity o rubella. Serologic testing is generally by EIA for either IgM or IgG anti rubella antibodies. Women who are not immune or have a low antibody titer should be vaccinated before becoming pregnant. Rubella vaccine is part of the trivalent measles, mumps, rubella vaccine most children in developed countries receive. -Textbook of diagnostic microbiology 4th edition, Mahon, Lehaman, Manuselis, page 224 Rubella virus is an enveloped virus belonging to the genus Rubivirus.
It causes the disease rubella or German measles, a mild febrile illness accompanied by an rythematous, maculopapular, discrete rash with postauricular and suboccipital lymphadenopathy. Like measles, rubella occurs in the winter and spring. The diseases are so familiar that as many as 50% of suspected measles cases are determined to be rubella. The rubella virus is transmitted by droplets. The virus is present in nasopharyngeal specimens or any secretions or tissue of infected infants, who shed the virus in large amounts for long periods. A rash starts on the face and spreads to the trunk and limbs. No rash appears on the palms and soles.
As many as 50% of individuals with rubella are asymptomatic. Transient polyarthralgia and polyarthritis can occur in children and are common in adults. Rubella would be a little concern if it did not cross the placenta of pregnant women and disseminate to fetal tissues, a condition referred to as congenital rubella syndrome. The results range from the birth of a normal infant to the birth of a severely impaired infant to fetal death and spontaneous abortion. The impact on the embryo is worse when the infectiondevelops in the earliest stages of pregnancy, because the rubella virus halts or slows the growth of the cells it infects.
An effective attenuated vaccine is available and should be administered to all children and young women before they become sexually active. The incidence of rubella in the United States has drop dramatically, from 364 cases in 1998 to approximately 10 cases annually since 2003. Rubella was declared no longer endemic in the United States in 2004. Direct examination of specimens by IF or EIA is recommended because isolation procedures are cumbersome. Serologic procedures are effective because any rubella antibody is presumed to be protective. The most sensitive serologic assays are the solid-phase and passive hemagglutination ensitive. 31 Rubella, also known as German measles. Is a viral infection of children and adults that resembles measles. It is characteristized by fever, rash and lymphadenophaty. The virus is in the Togaviridae family (genus rubivirus). Rubella virus is spread by droplets shed from the respiratory secretions of infected persons. The period of contagion extends from about 10 days before the appearance of the rash to 15 days after its onset. Many rubella infactions are subclinical, and most infections in the United States occur in unvaccinated immigrants or travelers, similar to measles.
For ymptomatic persons, a non-specific maculopapular rash begins on the face and moves down the body and often is accompanied by cervical and occipital lymphadenophaty and, at times, splenomegaly. The encephalitis can be complications, and serious congenital defects can be a consequence when the infection occurs during pregnancy. Diagnosis may be made by isolating the virus from urine, throat or nasopharyngeal specimens or by serologic testing to detect the development of antibodies. Congenital rubella infection is often diagnosed by detecting viral nucleic acids in the infant via a PCR assay. 822