Claudia Miller1, Susan Fuller
1, Susan Johnson
1, Jennifer Rota
2, Carol Hooker
3, Kathleen Steinmann
4, Diane Hirigoyan
4, and Kristen Ehresmann
1. (1) Immunizations, Tuberculosis, and International Health, Minnesota Department of Health, 717 Delaware Street SE, Minneapolis, MN, USA, (2) Centers for Disease Control and Prevention, Measles Virus Section, 1600 Clifton Road, NE, Mailstop C-22, Atlanta, GA, USA, (3) Hennepin County Community Health Department, 1011 First Street S, Suite 215, Hopkins, MN, USA, (4) Hennepin County Medical Center, 701 Park Avenue, Minneapolis, MN, USA
KEYWORDS:
Measles, serology, viral culture
BACKGROUND:
Isolation of measles virus is not recommended as a routine method to diagnose measles. Serologic testing is the most widely available and utilized laboratory method for confirming measles in patients presenting with a measles-like rash illness.
OBJECTIVE(S):
To describe incongruent laboratory test results on a likely case of modified measles.
METHOD(S):
Laboratory specimens were submitted to the CDC in an attempt to resolve incongruent laboratory test results for a patient with suspect measles.
RESULT(S):
On September 17, 2001, the MDH Public Health Laboratory reported a measles virus isolated from a nasopharyngeal (NP) swab collected on September 1, 2001 from a hospitalized 2-week-old Somali infant. The lab routinely conducts multiple tests on viral specimens. The infant’s clinical presentation was not consistent with measles; a diagnosis of apparent viral illness was made. Blood specimens from the infant and mother were collected on September 20, and tested for measles antibody. The infant and mother were found to be negative for measles IgM and positive for measles IgG which failed to support the diagnosis of measles. The serology specimens, the viral culture, and an original NP swab from the hospital were submitted to the CDC Measles Virus Laboratory, which confirmed all of the MDH results. A measles isolate on viral culture from a recently-arrived 10-year-old Somali case, previously laboratory-confirmed (via viral culture and serology), and hospitalized concurrently with the infant was also sent. This isolate was confirmed as measles; however, the genotype was different from that of the infant.
CONCLUSIONS(S):
Results of viral culture and serologic laboratory tests for measles on the 2-week-old Somali infant were verified but incongruent. Modified measles due to maternal antibody is a possible explanation for the unusual clinical presentation and lack of confirming measles serology.
LEARNING OBJECTIVES:
To better understand of the interpretation of measles laboratory results when disease is rare.
See more of Challenges in the laboratory Diagnosis of Measles
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