Mumps, 2010

During 2010, 8 cases of mumps (0.2 per 100,000) were reported. All 8 cases were laboratory-confirmed, including 2 cases confirmed by both positive PCR and IgM serology, 1 confirmed by PCR only, and 5 confirmed by IgM serology only. Two cases were epidemiologically linked to a source case. Six of the 8 cases were not epidemiologically linked, demonstrating that asymptomatic infections are occurring, and suggesting that mumps is underdiagnosed.

Cases ranged in age from 3 to 53 years. Two cases occurred in persons 0 through 18 years of age; 4 cases occurred in persons 19 through 33 years of age; 1 case occurred in persons 34 through 49 years of age; and 1 case occurred in persons 50 years and older. One case had a documented history of 2 doses of mumps-containing vaccine; 3 cases had a documented history of 1 dose. Three cases reported a history of receiving at least 1 dose of mumps-containing vaccine but these reports were not verified. No cases reported a previous history of mumps disease; and 1 case, born in 1957, had unknown history of disease as well as unknown vaccination status.

Mumps surveillance is complicated by nonspecific clinical presentation in nearly half of cases, asymptomatic infections in an estimated 20% of cases, and suboptimal sensitivity and specificity of serologic testing. Mumps should not be ruled out solely on the basis of negative laboratory results. Providers are also advised to test for other causes of sporadic parotitis including parainfluenza virus types 1 and 3, Epstein-Barr virus, influenza A virus, coxsackie A virus, echovirus, lymphocytic choriomeningitis virus, human immunodeficiency virus, and other noninfectious causes such as drugs, tumors, and immunologic diseases.

• For up to date information see>> Mumps
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2010