Posted May 15, 2019. Past health advisories and alerts are archived for historical purposes and are not maintained or updated.
Five new cases of measles have been diagnosed since Sunday May 12. One is a Pierce Co resident in his 40s who spent time at SeaTac Airport. The other 4 cases are all residents of western WA counties. While the exact exposure information for the new cases is not yet known, all spent time in SeaTac airport during their likely time of exposure or infectiousness. Find more details on places the new cases visited when they were infectious at Public Health — Seattle & King County, Tacoma-Pierce County Health Department and Snohomish Health District websites.
The Pierce County case’s rash onset was May 10/11, so he was exposed sometime between April 19 and May 1, 2019. Subsequently, this patient worked at SeaTac during the infectious period. Exposures in the community as a result of this case occurred between May 6 and May 11. We would expect cases from these exposures to occur between May 13 and June 1, 2019. Many exposed persons may have returned to other counties in the state after air travel. At this time, we do not know whether any Spokane County residents were exposed.
Measles is characterized by a generalized maculopapular rash, fever, and one or more of the following: cough, coryza, or conjunctivitis. Measles has a distinct prodrome that begins with fever and malaise. Additional symptoms can be conjunctivitis, coryza, cough, photophobia, and Koplik’s spots (which are pathognomonic but uncommonly observed). These spots are bluish-white specks on a rose-red background appearing on the buccal and labial mucosa usually opposite the molars. Temperatures may exceed 104⁰F, and usually fall two to three days after rash onset.
The prodrome generally lasts two to four days before the rash occurs. The rash is maculopapular and begins on the head often along the hairline and spreads downward reaching the hands and feet. After about five days, the rash fades in the same order in which it appeared. Measles is highly contagious, can cause pneumonia and encephalitis, and can be fatal.
Measles symptoms begin seven to 21 days after exposure and a person ill with measles is contagious for about four days before rash appears until four days afterward. More information on the clinical features of measles can be found here: www.cdc.gov/measles/hcp/index.html.
Most people in our state are immune to measles, so the public risk is low except for people who are unvaccinated, pregnant women, infants, and those with compromised immune systems.
The diagnosis of measles can be made by isolation of measles virus from a clinical specimen. Urine and respiratory samples are both good clinical specimens for viral isolation. Measles virus isolation is most successful when samples are collected within three days of rash onset. However, virus may still be present in specimens seven days following rash onset. WA State Public Health Lab can perform expedited RT-PCR on nasopharyngeal and urine specimens of measles on suspect cases; pre-approval from Spokane Regional Health District is required prior to submission.
The laboratory diagnosis of measles can also be made by detection of measles IgM antibody in a single serum specimen. Approximately 80% of measles cases in unvaccinated people have detectable IgM antibody by IgM capture EIA within 72 hours of rash onset. In most instances, a serum sample should be collected for measles IgM at the first clinical encounter. However, if a negative result is obtained from a specimen drawn less than 72 hours after rash onset, another specimen will be required. Additionally, persons vaccinated against measles may have a blunted or transient production of IgM; therefore, a negative IgM in vaccinated persons suspected of having measles should not be used to rule out the case.
|Attachments & Resources:|
|Measles Testing Guidance/Reporting Form||SRHD Measles Webpage|
|Measles Specimen Shipping Guide||WA Department of Health Measles Webpage|
|Measles Prophy & Treatment Guide||CDC Clinician Outreach Webinar on Measles – May 21, 11:00 am|