Saito M, Sunagawa T, Makino Y, Tadano M, Hasegawa H, Kanemura K, Zamami
           Y, Killenbeck BJ, Fukunaga T
           Department of Virology, Faculty of Medicine, University of the Ryukyus,
           Nishihara, Okinawa, Japan.
           Southeast Asian J Trop Med Public Health 1999 Jun;30(2):277-9

        Since 1974, no Japanese encephalitis (JE) case had been reported on
        Okinawa island in either Okinawan people or US servicemen. In 1991,
        three US marines stationed on Okinawa island developed encephalitis
        symptoms. Neutralization (N) test and IgM-capture ELISA were carried out
        on the serial samples of serum and cerebrospinal fluid (CSF) taken from
        the patients. In each patient N test on both serum and CSF samples gave
        a significant rise in JE antibody titer in the comparison between the
        acute and convalescent phases, indicating that all the cases were
        infected with JE virus. The IgM-capture ELISA also showed a significant
        rise of antibody titer of the serum and CSF samples in the convalescent
        phase in patients 2 and 3, while in patient 1 a significant rise in IgM
        antibody was observed in the serum sample, but not in the CSF sample.
        None of the patients had been administered JE vaccine. This report
        underscores the importance of JE vaccination.