Hemoagglutination inhibiting antibody of Japanese Encephalitis In the sera of inpatients of a hospital in Kurashiki City and that in the sera of an upper secandary school pupils in Kurashiki City (EpidemiologIcal Study on Japanese Encephalitis, 68)

The rale of inpatients and high school pupils in Kurashiki City having value under 10 in HI reaclion was 11.4% and 15.2% respectively, suggesting that about one seventh of inhabitants have relatively a few HI antibody just before the season of outbreak of Japanese Encephalitis in Southern part of Okayama Prefecture

Seasonal level of hemoagglutinin inhibitinlt and its 2-mercaptoethanol sensitive antibody in the sera of swine (Epidemiological Study on Japanese Encephalitis, 67)

Seasonal level of hemoagglutinin inhibiting and its 2 -mercaptoethanol sensitive antibody in the sera of swine were researched and the following results were obtained. 1. The positive rate of hemoagglutination inhibit reaction (HI reaction) on swine showed 100% at maximum in the middle of September. 1980. The positive rate of 2-ME sensitive antibody showed the titer of over 1 : 40 with all swine examined in the middle of August, 1980. 2. The positive rate of HI reaction of inhabitants at Mukaiyama in Kurashiki City was 76.0% (on 8th in July, 1980) indicating the rather big decrease being compared with annual value of 90.6%, in 1976. Date indicated that increase In JE virus in swine as source of infection thought to be a vector of JE, caused a genuine case of JE, in 1980, as described below. 3. Higher positive rate of HI reaction and 2-ME sensitive positive rate of swine were observed in 1980. 4. One patient who suffered from JE was found In Kurashiki City in 1980. 5. Henceforth and continuously, Japanese Encephalitis should be investigated, above all on its occurance order with the number or Ct or the positive rate of hemoagglutination inhibit reaction in inhahitants and swine, etc. considering that J.E. has a high lethality rate and often leaves the terrible J. E. residue to patients

Epidemiological and serological studies on influenza Part 1. Plaque cloning from influenza B isolates and cultivation of B type reference strains in the presence of homologous antibody

Plaque cloning was conducted with MDCK cells on nine influenza B isolates from 1973 to 1977 in Okayama Prefecture, following hemagglutination inhibition test. Hemagglutinin (HA) antigenicity of clones isolated from two out of four B/Gifu/2/73 like isolates in 1973 varied greatly, including B/Kanagawa/3/76 like viruses, and the clones from B/Kanagawa/3/76 like isolate in 1974 also varied greatly, including B/Kanagawa/3/76 like and its variants. One clone from four B/Kanagawa/3/76 like isolates in 1977 indicated the HA antigenicity of B/Gifu/2/73 variant. After B/Gifu/2/73 and B/Kanagawa/3/76 strains were twice cloned by direct plaque to plaque on MDCK cells, these viruses were cultivated in the presence of homologous antibody. Tenth cultivated viruses and their clones indicated the HA antigenicity of each variant. Hemagglutinin antigenicity of both clones from the isolates and the cultivated viruses in the presence of antibody were stable after fifth cultivation in MDCK cells. From these results, it is suggested that the prevarent virus may be pre-isolated by plaque cloning from and cultivation in the presence of antibody of prevarent isolates

Serologic epidemiological studiess on influenza Part 1. Annual variation of HI level against various kinds of influenza antigen in the serum of inhabitants and estimation of past history of infection

The hemagglutination inhibition (HI) test was conducted with serial sera of 63 persons, collected annually in 1972, 1973 and 1974, using 4 strains of A Hong Kong and 5 strains of influenza B virus as antigen. It was proved that the incidence of influenza A was reduced by means of lower positive rates (of titers 64 or over) of HI titers than prior observation before epidemic. The fact that the incidence of influenza B was reduced is proved by the more lower positive rates. From the result that HI titers against B/Osaka/2/70 strain and B/Hong Kong/72 viruses differed according to age distribution, it is suggested that B/Osaka/2/70 strain must have been prevalent about 50 years ago and B/Hong Kong/72 viruses have been about 30 years ago