Difficulty with mumps diagnosis: What is the contribution of mumps mimickers?

BACKGROUND: Mumps is a vaccine preventable disease that typically presents with unilateral or bilateral parotitis. In February 2007, mumps re-emerged in university students in Nova Scotia. Despite highly sensitive methods for mumps virus detection, only 14% (298/2082) of cases during the peak of the outbreak were laboratory confirmed. OBJECTIVES: Due to the low positivity rate, this study investigated whether infection with other viral pathogens caused mumps-like presentations during the outbreak. STUDY DESIGN: 148 buccal specimens from patients who presented with unilateral or bilateral parotitis but had negative laboratory tests for mumps virus were tested for Epstein-Barr virus (EBV) and cytomegalovirus (CMV) by quantitative PCR and 21 different viral markers using the Luminex xTAG Respiratory Virus Panel (RVP). Companion sera to each buccal specimen were available for EBV and CMV serology to differentiate acute infection from reactivation. RESULTS: No correlation was observed since viral pathogens were detected in both the parotitis and non-parotitis groups. CONCLUSION: Although there was co-circulation of other viral pathogens during the mumps outbreak, no difference was observed in the prevalence between patients who presented with or without parotitis. The low positivity rate for specimens submitted for mumps diagnostics was likely the result of increased Public Health messaging and physician inexperience in recognizing mumps infection, suggesting the clinical acumen for mumps diagnosis based solely on clinical presentation is low.