Mumps is an acute viral infection caused by a member of the Paramyxoviridae family. Early symptoms include body aches, loss of appetite, fatigue, headache, and low grade fever followed by parotitis. Parotid swelling is unilateral initially, but later becomes bilateral. Fever usually resolves within 3 to 5 days, and parotid swelling within 7 to 10 days.
Mumps vaccination in the United States began in 1967. Before that time, approximately 186,000 cases were reported each year. The actual incidence was believed to be much higher due to underreporting. Since vaccination began, there has been a 99% decrease in mumps cases in the United States. The number of reported mumps cases has ranged from a few hundred to a few thousand per year. In 2006, more than 6,500 cases were reported, primarily involving college aged students living the in the Midwest.
Another resurgence appears to be occurring this year. As of December 3, 2016, 46 states and the District of Columbia have reported 4,258 mumps cases to the CDC. Seven states have reported more than 100 cases including AR, IA, IN, IL, MA, NY, and OK.
Outbreaks can occur in highly vaccinated communities, particularly in close-contact settings. In recent years, outbreaks have been reported from schools, colleges and camps. Behaviors that result in exchanging saliva, such as kissing or sharing utensils, cups, lipstick or cigarettes, increase spread of the mumps virus. Mumps outbreaks can occur any time of year. High vaccination coverage helps limit the size, duration and spread of mumps outbreaks.
Laboratory testing should be performed if mumps is suspected. Tests for acute mumps infection include serum mumps IgM and IgG antibody and real-time reverse transcription polymerase chain reaction (RT-PCR) on a buccal swab specimen. The presence of IgM antibodies usually indicates acute infection. The presence of IgG generally indicates past exposure and immunity from vaccination. The early collection of buccal swab specimens provides the best means of laboratory confirmation, particularly among patients who have been vaccinated. RT-PCR may be negative if the buccal swab is collected more than 3 days after onset of parotitis.