Five cases of mumps were reported in 2002; 39 cases have been reported during the last 5 years. Two of the case-patients reported in 2002 were children. One was a 5-year-old, white, non-Hispanic male with a history of one dose of MMR given at 11 months of age. The other was an 8-year-old, black, non-Hispanic female with a history of one dose of MMR given at 20 months of age. Of the three adult case-patients, two were Asian and one was white. Two of the adults had unknown histories of mumps disease or vaccination. The third adult reported receiving two doses of MMR vaccine administered outside the U.S. Adults represent an increasing percentage of mumps cases reported in Minnesota, highlighting the need to assess their mumps immunization status and to implement recommendations to vaccinate adults born in 1957 or later who have not received a second dose of MMR.
All five cases 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, as 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 to 5 weeks later; tests should be run as paired sera. Mumps also can be confirmed by viral culture on throat washings, urine, or spinal fluid specimens. Specimens for viral culture should be collected during the first 5 days of illness.