Two confirmed cases of measles were reported to MDH during 2002. The cases were confirmed by positive IgM serologic tests for measles; viral culture for measles was not performed for either case. Both cases were considered international importations. The first case occurred in a 29-year old female visitor to the U.S. She developed a measles-like rash 7 days after traveling from the Ukraine. The patient reported a history of measles vaccination as a child and no known exposure to measles in the Ukraine. Despite a thorough investigation of emergency room contacts by hospital infection control staff, no subsequent transmission was reported from this case. The second case occurred in an 8-month-old unvaccinated child. Eleven days after returning from a lengthy visit to the Philippines, the child developed a measles-like rash. No known exposure to measle occurred in the Philippines. All three of the child's siblings had been vaccinated for measles, and no transmission from this case was reported. International importation, a common source of measles in the U.S. and Minnesota, accounted for six (75%) of the eight measles cases reported in Minnesota during the past 5 years.
CDC recommends serologic testing for measles and rubella for patients with rash illnesses compatible with either disease. Blood specimens for IgM serology should be drawn at least 72 hours after rash onset. Blood specimens for acute and convalescent IgG serology should be drawn within 4 days of rash onset and again 3 to 5 weeks later. Acute and convalescent specimens should be tested as paired sera. Specimens for viral culture may be obtained from urine, nasopharyngeal swabs, or throat swabs and are ideal for genotyping. Because measles viral load peaks prior to rash onset, specimens should be collected as early as possible. Specimens for viral culture should be collected at the same time as or prior to serologic specimens. Viral cultures and/or serologic specimens should be sent to MDH to be forwarded to CDC for genotypic strain identification, which provides important epidemiologic data for tracking patterns of measles importation and transmission. MDH strongly encourages submission of specimens for viral culture for all suspected measles cases.