Viruses detected among sporadic cases of parotitis, United States, 2009-2011.

Background: Sporadic cases of parotitis are generally assumed to be mumps, which often requires a resource-intensive public health response. This project surveyed the frequency of viruses detected among such cases.

Methods: During 2009-2011, 8 jurisdictions throughout the United States investigated sporadic cases of parotitis. Epidemiologic information, serum, and buccal and oropharyngeal swabs were collected. Polymerase chain reaction methods were used to detect a panel of viruses. Anti-mumps virus immunoglobulin M (IgM) antibodies were detected using a variety of methods.

Results: Of 101 specimens, 38 were positive for a single virus: Epstein-Barr virus (23), human herpesvirus (HHV)-6B (10), human parainfluenza virus (HPIV)-2 (3), HPIV-3 (1), and human bocavirus (1). Mumps virus, enteroviruses (including human parechovirus), HHV-6A, HPIV-1, and adenoviruses were not detected. Early specimen collection did not improve viral detection rate. Mumps IgM was detected in 17% of available specimens. Patients in whom a virus was detected were younger, but no difference was seen by sex or vaccination profile. No seasonal patterns were identified.

Conclusions: Considering the timing of specimen collection, serology results, patient vaccination status, and time of year may be helpful in assessing the likelihood that a sporadic case of parotitis without laboratory confirmation is mumps.