抄録
1) Guinea pigs have been generally used for poducing positive sera for use with complement fixing antigen for Japanese B encephalitis. But cats are superior to guinea pigs for this purpose, particularly in point of view of large volume of sera and of ease in breeding.
2) Japanese B encephalitis virus has been isolated from the brain of Toyokawa who died from Japanese B encephalitis in 1951. This virus is not different from the virus of Nakagawa strain of Japanese B encephalitis in the complement fixation reaction.
3) The patients of Japaness B encephalitis, whose sera are positive in the complement fixation reaction, are very few in 1951 and the dates of the onset of the disease are later in 1951 than in 1949 and 1950.
4) In 1951, in Kyoto Prefecture, the dissemination of Japanese B encephalitis virus in human beings and in guinea pigs is much rougher than in 1949 and in 1950.
5) High titers of neutralizing antibodies are demonstrated in the sera of many normal human beings in 1951 in which no complement fixing antibodies are demonstrated.
6) All titers of complement fixing antibodies of sera of patients, who falled in Japanese B encephalitis in 1949, are 4 to lower than 2, when they are bled and tested in 1951.
