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The measles virus is a member of the Paramyxoviridae family of viruses, which include parainfluenza virus serotypes 1-4, mumps, respiratory syncytial virus (RSV), and metapneumovirus. The measles virus is among the most highly contagious infectious diseases among unvaccinated individuals and is transmitted through direct contact with aerosolized droplets or other respiratory secretions from infected individuals. Measles has an incubation period of approximately 8 to 12 days, which is followed by a prodromal phase of high fever, cough, coryza, conjunctivitis, and malaise. Koplik spots may also be apparent on the buccal mucosa and can last for 12 to 72 hours.(1,2) Following this phase, a maculopapular, erythematous rash develops beginning behind the ears and on the forehead and spreading centrifugally to involve the trunk and extremities.
Immunocompromised individuals, pregnant women, and those with nutritional deficiencies, are particularly at risk for serious complications following measles infection, which include pneumonia and central nervous system involvement.(1,3)
Following implementation of the national measles vaccination program in 1963, the incidence of measles infection has fallen to <0.5 cases per 1,000,000 population and the virus is no longer considered endemic in the United States.(4) Measles outbreaks continue to occur in the United States due to exposure of nonimmune individuals or those with waning immunity to infected travelers. The measles outbreak in 2011 throughout Western Europe emphasizes the persistence of the virus in the worldwide population and the continued need for national vaccination programs.(5)
The diagnosis of measles infection is often based on clinical presentation alone. The presence of IgM-class antibodies suggests recent infection, but should not be used alone to diagnose measles infection. Screening for IgG-class antibodies to measles virus will aid in identifying nonimmune individuals.
Laboratory diagnosis of measles virus infection
Determination of immune status of individuals to the measles virus
Documentation of previous infection with measles virus in an individual without a previous record of immunization to measles virus
The presence of IgM-class antibodies, with or without the presence of IgG-class antibodies to measles virus may support a clinical diagnosis of recent/acute phase infection with the virus. IgM results alone should not be used to diagnose measles virus infection.
The absence of IgM-class antibodies suggests lack of an acute phase infection with measles virus. However serology may be negative for IgM-class antibodies in early disease, and results should be interpreted in the context of clinical findings.
Testing for IgM-class antibodies to measles should be limited to patients with clinically compatible disease.
The presence of detectable IgG-class antibodies, in the absence of IgM-class antibodies, indicates prior exposure to the measles virus through infection or immunization. These individuals are considered immune to measles infection.
The absence of detectable IgG-class antibodies suggests the lack of a specific immune response to immunization or no prior exposure to the measles virus. These individuals are considered nonimmune to measles virus infection.
A serum specimen drawn during the acute phase of infection or soon after vaccination may yield negative for IgM- or IgG-class antibodies.
Rare heterotypic IgM responses to measles virus have been reported in patients with rubella virus, chronic active hepatitis, systemic lupus, and infectious mononucleosis.(6)
IgG-class antibodies to measles virus may be present in serum specimens from individuals who have received blood products within the past several months, but who have not been immunized or have experienced past infection with this virus.
Negative (reported as negative or positive)
Vaccinated: positive (> or =1.1 AI)
Unvaccinated: negative (< or =0.8 AI)
1. Perry RT, Halsey NA: The clinical significance of measles-a review. J Infect Diseases 2004;189(Supp 1):S4-S16
2. Babbott FL, Gordon JE: Modern measles. Am J Med Sci 1954;228:334-361
3. Liebert UG: Measles virus infections of the central nervous system. Intervirology 1997;40:176-184
4. Morbidity and Mortality Weekly Report: Measles-United States, 1999. 2000;49(25):557-560
5. Morbidity and Mortality Weekly Report: Increased Transmission and Outbreaks of Measles-European Region 2011;60(47):1605-1610
6. 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