Six cases of mumps were reported during 2001; 34 cases have been reported in Minnesota in the last 5 years. Four of the six case-patients reported in 2001 were white, non-Hispanic adults, with ages ranging from 43 to 62 years. All four adult cases had no (or unknown) mumps vaccination history. Two case-patients were children. A 4-year-old patient born in the Dominican Republic had an unknown immunization history. An 8-year-old patient was a white, non-Hispanic female with a history of one dose of MMR at 15 months of age. Adults represent an increasing proportion of mumps cases reported in Minnesota, highlighting the need to assess adults' immunization status and to implement recommendations for mumps vaccination for those born in 1957 or later.
All six cases reported in 2001 were laboratory-confirmed by positive IgM serology; however, none had convalescent serum specimens collected to demonstrate a rise in serum IgG antibody. Both IgM and IgG serologic testing should be performed on suspected mumps cases, since false-positive indirect immunofluorescent antibody tests for mumps IgM have been reported. Serologic specimens for mumps IgM should be drawn on or after the third day of swelling. Specimens for acute and convalescent serum IgG should be drawn as soon as possible after onset of swelling and 3-5 weeks later; tests should be run as paired sera. Mumps also can be confirmed by viral culture using throat washings, urine, or spinal fluid specimens. Specimens for viral culture should be collected during the first 5 days of illness.