Two hundred sixty-one men in a Marine Battalion on Okinawa were studied for the development of hemagglutinin-inhibiting antibodies against Japanese encephalitis virus. Fifty subjects developed hemagglutinin inhibiting antibodies during the summer of 1960. One man had an initial antibody titer of 1/10; this low titer was found to be subsequently increased. During the study period, in none of these 51 men was there any evidence of disease symptoms resembling those due to Japanese encephalitis virus infection. Overt encephalitis was confirmed serologically in one marine from the same Battalion who was not in the study group.
NAMRU-2 Fellow, 1960-1961, from the Department of Medicine, National Taiwan University, School of Medicine, National Taiwan University, School of Medicine, Taipei, Taiwan.
Visiting Scientist, 1960–1961, NAMRU-2, on sabbatical leave from the Division of Virology, Department of Infectious Diseases, University of California School of Medicine, Los Angeles, California.