Rubella Virus

Rubella is a contagious viral illness, which, prior to vaccination, was responsible for a significant number of fetal losses and congenital abnormalities. The reported number of rubella cases in the U.S. is low enough that the CDC considers it eliminated in 2004.

Tabs Content

Clinical Overview

Diagnosis

Indications for Testing

Prenatal screening for evidence of immunity (presence of maternal antibodies)
Typical symptoms in unvaccinated patient – rash, fever, headache, pink eye, malaise, lymphadenopathy, cough, rhinitis

Criteria for Diagnosis

World Health Organization (WHO) case definition for congenital rubella syndrome (CRS)
- Suspected case – any infant <1 year in whom a health worker suspects CRS
  - Infant presents with heart disease and/or suspicion of deafness and/or ≥1 of the following eye signs – white pupil (cataract), diminished vision, pendular movement of the eyes (nystagmus), squint, smaller eye ball (microphthalmos), or larger eye ball (congenital glaucoma)
  - Infant’s mother has a history of suspected or confirmed rubella during pregnancy, even when the infant shows no signs of CRS
- Clinically confirmed case – an infant in whom a qualified physician detects 2 of the complications in section A or 1 from section A and 1 from section B
  - Section A – cataracts, congenital glaucoma, congenital heart disease, hearing impairment, pigmentary retinopathy
  - Section B – purpura, splenomegaly, microcephaly, developmental delay, meningoencephalitis, radiolucent bone disease, jaundice with onset within 24 hours of birth
- Laboratory-confirmed case – infant with rubella IgM antibody who has clinically confirmed CRS
- Congenital rubella infection – infant with rubella IgM antibody who does not have clinically confirmed CRS
Rubella/German measles case definition (CDC, 2013)

Laboratory Testing

CDC manual for surveillance of rubella
Rubella laboratory testing (CDC, 2016)
Serology
- Appearance of clinical symptoms is associated with appearance of both IgG and IgM antibodies
  - IgM antibodies
    - Detectable a few days after onset of symptoms
    - Peak 7-10 days later
  - May consider fetal IgM serology if fetal infection suspected
- Prenatal screening – test women before pregnancy to confirm presence of IgG antibodies indicating previous infection and immunity
- Serologic testing for rubella and CRS in low prevalence setting
Polymerase chain reaction (PCR)
- Usually throat or urine samples
- Amniotic fluid when fetus is at least 2 weeks of age to identify fetal infection
Congenital – see CDC testing recommendations

Differential Diagnosis

Background

Epidemiology

Incidence – <10 cases per year in the U.S. (all contracted outside the country since 2012)
- CRS – <2/100,000 births
Age – usually children who are unvaccinated
Transmission
- Via droplets, aerosol particles – close contact required

Organism

Rubella, an RNA virus, is a member of the Togaviridae family
Virus infects cells in the upper respiratory tract and replicates in the lymphoid system; virus then spreads to other organs

Clinical Presentation

Transmission can occur up to 7 days before and 7 days after onset of rash
In children and adults, infection usually results in mild, exanthematous disease
- Adults are more likely to experience prodromal phase – fever, headache, sore throat, cough, conjunctivitis
- Rare complications – arthralgias and arthritis, thrombocytopenia, hemorrhage, and encephalitis
In pregnant women, particularly during first trimester, infection can result in fetal death or congenital abnormalities
- Disease can be asymptomatic
- Congenital abnormalities include
  - Ophthalmologic – cataracts, glaucoma, iris hypoplasia, retinopathy
  - Otorhinolaryngologic – sensorineural or central deafness
  - Cardiac – patent ductus arteriosus, pulmonary stenosis, pulmonary arterial hypoplasias, myocarditis
  - Central nervous system – developmental delay with central nervous system calcifications, microcephaly
  - Dermatologic – petechia, purpura
- 10-20% of newborns infected in utero will die during the first year of life
- Because complications in utero are so severe, diagnosis during first trimester may result in decision to terminate pregnancy
- Delayed manifestations
  - Insulin-dependent diabetes mellitus
  - Panencephalitis (rare)
  - Thyroid dysfunction
  - Behavioral disorders

Prevention

Vaccination programs have resulted in marked decrease in infections
- Estimated >95% of children in U.S. are vaccinated (recommended between ages 12-15 months)
- Vaccine is live, attenuated virus and contraindicated in pregnant women

ARUP Lab Tests

Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

Rubella Antibodies, IgG and IgM 0050552
Method: Semi-Quantitative Chemiluminescent Immunoassay

Recommended Use

Aid in diagnosis of suspected rubella infection

Follow-up

If test results are equivocal, repeat testing in 10-14 days

Rubella Antibody, IgG 0050771
Method: Semi-quantitative Chemiluminescent Immunoassay

Recommended Use

Determine seroreactivity of women of childbearing age or provide evidence of vaccination/past infection

Medical Reviewers

Couturier, Marc Roger, PhD, D(ABMM), Medical Director, Microbial Immunology, Parasitology and Fecal Testing, and Infectious Disease Antigen Testing at ARUP Laboratories; Associate Professor of Clinical Pathology, University of Utah

References

Guidelines

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Recommended Immunization Schedule for Children and Adolescents Aged 18 Years or Younger. United States, 2018. Centers for Disease Control and Prevention. Atlanta, GA [Last updated: Jan 2018; Accessed: Apr 2018]
Centers for Disease Control and Prevention (CDC). Recommendations from an ad hoc Meeting of the WHO Measles and Rubella Laboratory Network (LabNet) on use of alternative diagnostic samples for measles and rubella surveillance. MMWR Morb Mortal Wkly Rep. 2008; 57(24): 657-60. PubMed
U.S. Department of Health and Human Services, Centers for Disease Control and Prevention (CDC). Recommended Immunization Schedule for Adults Aged 19 Years or Older. United States 2018. Center for Disease Control and Prevention. [Last updated: Apr 2018; Accessed: May 2018]
Centers for Disease Control and Prevention. Manual for the Surveillance of Vaccine-Preventable Diseases. Centers for Disease Control and Prevention. Atlanta, GA [Updated: Apr 2018; Accessed: Apr 2018]

General References

Neu N, Duchon J, Zachariah P. TORCH infections. Clin Perinatol. 2015 Mar;42(1):77-103, viii. PubMed

References from the ARUP Institute for Clinical and Experimental Pathology^®

Owen WE, Martins TB, Litwin CM, Roberts WL. Performance characteristics of six IMMULITE 2000 TORCH assays. Am J Clin Pathol. 2006; 126(6): 900-5. PubMed

Shirts BH, Welch RJ, Couturier MR. Seropositivity rates for measles, mumps, and rubella IgG and costs associated with testing and revaccination. Clin Vaccine Immunol. 2013; 20(3): 443-5. PubMed

Last Update: March 2018


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	Rubella Virus. ARUP Consult^©. Retrieved October 15, 2018, from: https://arupconsult.com/content/rubella-virus