KEYWORDS:
Measles, Surveillance, Laboratory methods, Epidemiology, Outbreak control

BACKGROUND:
In early 2001, twelve measles cases were reported to Public Health-Seattle & King County (PHSKC). After the first case was diagnosed on January 18, a provider alert, multiple press advisories, and Internet postings were used to advise the public about settings where potential measles exposures had occurred. Enhanced public and provider awareness resulted in 150 measles-related rash illness reports to PHSKC by March 19 (one maximum incubation period for measles after the rash onset of the last confirmed case in a King County resident).

OBJECTIVE(S):
Review the roles of the epidemiologist and microbiologist in measles surveillance and rapid case identification in an outbreak setting. Discuss the importance of the clinical case definition when using serologic testing for measles diagnosis. Discuss the importance of good communications during an outbreak.

METHOD(S):
The CDC clinical case definition as well as an alternative outbreak case definition and the usefulness of both related to serologic testing are discussed. Proper specimen collection and measles serologic tests currently in use at the Washington State Department of Health Laboratories are reviewed. We show how the microbiologist uses epidemiologic information such as specimen timing in relation to the onset of rash in interpretation of measles-specific IgM and IgG results.

RESULT(S):
Rapid investigation of reported rash illnesses and 24-hour turn around time for measles IgM-specific serology facilitated optimum measles diagnosis and outbreak control.

CONCLUSIONS(S):
Optimum measles surveillance requires clear understanding between epidemiology and laboratory staff for rapid diagnosis of measles and outbreak control. Serologic testing should be done only when the clinical illness meets a measles clinical case definition.

LEARNING OBJECTIVES:
Understand the mutually important work of the epidemiologist and the microbiologist in measles surveillance and control. Learn ways to optimize communication during a measles outbreak.