[Clinical, epidemiological and etiological studies of adult aseptic meningitis: Report of 13 cases with mumps meningitis].

We experienced 13 cases (29.8 ± 7.0 years) of mumps meningitis and 365 cases of adult aseptic meningitis during 11 years from 2004 to 2014. A small epidemic of mumps occurred for 3-4 years, and the incidence rate of adult mumps meningitis coincided with the epidemic without seasonal fluctuation. Parotitis was observed in 8 of the 13 mumps meningitis patients (61.5%) and orchitis in 2 of 7 male patients (28.6%). There were no differences in clinical manifestations, laboratory findings, and outcome between patients with adult mumps meningitis and those with echovirus 9 meningitis (9 patients), except for the low frequency of nausea/vomiting and a high percentage of mononuclear cells of the cerebrospinal fluid in those with mumps. Eight patients had contact with persons with mumps before the symptomatic stage of meningitis. Only one patient had received mumps vaccination in childhood. On the basis of the values of the anti-mumps IgM and IgG antibodies, we speculated primary infection and the re-infection of mumps in 6 and 2 patients, respectively. Moreover, second vaccine failure was suggested in the vaccinated patient.