Interpretive Handbook

Measles (rubeola) virus is a member of the family paramyxoviridae, which also includes mumps, respiratory syncytial virus, and parainfluenza viruses. Clinical infection with measles virus is characterized by a prodromal phase of high fever, cough, coryza, conjunctivitis, malaise, and Koplik's spots on the buccal mucosa. An erythematous rash then develops behind the ears and over the forehead, spreading to the trunk.

Measles virus is highly contagious; pregnant women, immunocompromised, and nutritionally deficient individuals are at particularly high risk for serious complications of pneumonia and central nervous system involvement.(1-3)

Since intensive immunization began in the United States more than 2 decades ago, the incidence of measles infection has been reduced from approximately 1/2 million cases annually in the 1960s to fewer than 500 cases in recent years. Atypical measles can occur in patients who received killed measles virus vaccine and subsequently have been infected with the wild type strain of the virus.(4) In addition, many individuals remain susceptible to measles virus because of vaccine failure or nonimmunization. Screening for antibody to measles virus will aid in identifying these nonimmune individuals.

Determining acute-phase infection with rubeola (measles) virus

As an aid in identifying nonimmune individuals

Positive IgM results, with or without positive IgG results, indicate a recent infection with measles virus.

Positive IgG results coupled with a negative IgM result indicate previous exposure to measles virus and immunity to this viral infection.

Negative IgG and IgM results indicate the absence of prior exposure to rubeola and nonimmunity.

Equivocal results should be followed up with a new serum specimen within 10 to 14 days.

Grossly contaminated, hemolyzed, hyperlipemic, or icteric serum may yield unreliable results. Serum specimens must not be heat-inactivated prior to testing.

A serum specimen drawn during the acute phase of infection when only low titers of IgM are present may yield negative results by this procedure.

Rare heterotypic responses with rubella virus and varicella virus have been reported from measles virus.(5)

Negative (reported as positive, negative, or equivocal)

Individuals who are immune to rubeola will have positive IgG test results by the EIA method and negative IgM test results by the IFA method. Those who are nonimmune will have negative test results by both methods. Recent infection with measles virus will be indicated by a positive IgM antibody result. The EIA test sensitivity is 96.9% and specificity is 100%. Similar performance characteristics are provided by the IFA test.

1. Liebert UG: Measles virus infections of the central nervous system. Intervirology 1997;40:176-184

2. Norrby E, Kristensson K: Measles virus in the brain. Brain Res Bull 1997;44:213-220

3. Sable CA, Hayden FG: Orthomyxoviral and paramyxoviral infections in transplant patients. Infect Dis Clin North Am 1995;9:987-1003

4. Matsuzono Y, Narita M, Satake A, et al: Measles encephalomyelitis in a patient with a history of vaccination. Acta Paediatr Jpn 1995;37:374-376

5. Cremer NE, Devlin VL, Riggs JL, Hagens SJ. Anomalous antibody responses in viral infection: specific stimulation or polyclonal activation? J Clin Microbiol 1984;20:468-472

6. Gershon AA, Krugman S: Measles virus. In Diagnostic Procedures for Viral, Rickettsial and Chlamydial Infections. 5th edition. Edited by EH Lennette, NJ Schmidt. Washington, DC, American Public Health Association, Inc., 1979, pp 665-693