岡山医学会 Acta Medica Okayama 0030-1558 78 1.suppl 1966 1964年度岡山市および倉敷市における日本脳炎の流行と蚊の季節的消長 77 84 EN Seiiti Inatomi Kazuo Itano Mitiya Kimura Taneo Tsubota Yosihiro Ito Daigoro Sakumoto Mosquitoes were collected by light-trapping twice a week during nights totally 38 times from Okayama City, 25 times from Ichinomiya near Okayama City, and 34 times and 40 times from Mizushima and Hama in Kurashiki City, and the number of mosquitoes trapped was 5, 209, 331, 144, 782, and 4, 395 respectively. The maximum occurrence of mosquitoes was on the 10th at Hama, on the 13th at Okayama, on the 17th at Mizushima in July, and on the 3rd of August at Ichinomiya. The incidence of Japanese B encephalitis was reported three weeks after the maximum occurrence of mosquitoes in each spot. No potential conflict of interest relevant to this article was reported.

岡山医学会 Acta Medica Okayama 0030-1558 78 1.suppl 1966 1963年度岡山市および倉敷市における日本脳炎の流行と蚊の季節的消長 69 75 EN Seiiti Inatomi Kazuo Itano Mitiya Kimura Taneo Tsubota Yosihiro Ito Daigoro Sakumoto Mosqnitoes were collected by light-trapping twice a week during nights from May through September, 1963, totally 30 times from two spots of Kurashiki City and 32 times from one spot of Okayama City. The number of mosquitoes collected was 1, 563 and 2, 882 from Hama and Mizushima in Kurashiki City respectively, and 9, 185 from Okayama City. Culex tritaeniorhynchus first occurred at the end of May at Mizushima, in the middle of June at Okayama, and in the beginning of July at Hama, and reached their peak in July, on the 23rd at Mizushima, on the 29th at Okayama, and on the 30th at Hama. While the first incidence of Japanese B encephalitis at Okayama and Mizushima was reported approximately three weeks after the maximum occurrence of the mosquito, it was as early as on the 20th of July at Hama being ten days ahead of the peak. No potential conflict of interest relevant to this article was reported.

岡山医学会 Acta Medica Okayama 0030-1558 78 1.suppl 1966 日本脳炎ウイルスの電子顕微鏡的研究 61 68 EN Kiyoshi Hiraki Zensuke Ota Shinya Suzuki Kenji Takahashi Masahito Muguruma The ultrastructure and developmental process of Japanese B encephalitis virus were studied by electron microscopy in porcine kidney stable (PS) cells infected with the Mukai strain of Japanese B encephalitis virus. The virus and PS cells were kindly supplied by Dr. Y. Kanda Inoue at the Virus Institue of Kyoto University. PS cells were cultivated in bottles containing 10% calf serum and 0.5% lactalbumin hydrolyzate in Earle's balanced solution. Titration of cellassociated virus was estimated by cytopathic effect. At various intervals following infection, the cells were fixed in buffered 1% osmium tetroxide solution, embedded in methacrylates and cut on a Leitz ultramicrotome. After sections were stained in saturated uranyl acetate solution, they were observed in the Hitachi type HU ll electron microscope. Japanese B encephalitis virus particles were hexagonal in thin sections and approximately 40 mμ in the longest diameter, composed of the outer membrane, 30Å in thickness, viroplasm, 30Å in thickness and an electron-dense nucleoid, 25 mμ in diameter, After the virus particles developed in the process of budding on the wall of the cytoplasmic vacuole, they were densely packed in the vacuole usually in random arrangement and occasionally in crystalline arrays. The vacuole containing the virus particles gradually migrated to the cell surface and liberted the particles to the exterior of the cell through a narrow canaliculus which was formed between the vacuole and cell surface. No potential conflict of interest relevant to this article was reported.

岡山医学会 Acta Medica Okayama 0030-1558 78 1.suppl 1966 日本脳炎の脳波学的研究 特にその診断と予後の監視に於ける脳波の応用について 51 59 EN Eiji Hamamoto Shunsuke Ohtahara Yoshito Takabatake Yukio Mukai Eiji Oka Minoru Ohno It is the purpose of this paper to present an electroencephalographic study on Japanese B encephalitis for elucidating its pathophysiology, aiding its diagnosis and treatment and for evaluating its prognosis. Electroencephalograms of 19 patients admitted to our clinic were investigated in their courses of Japanese B encephalitis. We clinician have had only one method to know cerebral pathology in encephalitis, that is to judge on neurological signs and symptoms, and yet it is not entirely reliable. However, EEG can disclose pathological process which has been taken place and is going on in the acute stage in the brain of the patient and we can grasp whole pathology objectively by EEG. Besides this, we suppose we can know the prognosis of the patients more accurately by reading EEG than other conventional methods. In the acute stage, there is a bilateral symmetric monorhythmic continuous high voltage delta activity of 1 to 2.5c/s with frontal dominancy. This pattern is very characteristic of the Japanese B encepaalitis. This finding suggests that the primary lesion of this disease is located in the subcortical structure, especially in the ascending reticular formation of the brain stem. Electroencephalographic findings in the process of Japanese B encephalitis are illustrated in Table 1 Patients recover from encephalitis with the EEG findings in the order of 1) to 7) (from up to down) shown on the Table 1. in his EEG if the patient follows uneventful course. We have confirmed it takes about 1 year for the patient to follow the above-mentioned process and finally attain normal EEG. This is quite different from in the case of aseptic meningitis. If the patient fails to follow the above-mentioned course and stop at some stage in the middle, we consider this patient has much possibility to develop mental deficiency or other nourological sequelae. In the case that patient shows epileptic discharge in his EEG during convalescent period, we predict this patient will develop clinical epilepsy sooner or later. We, therefore, think it very important to have successive EEG study at least for four years on the patient with encephalitis even after his clinical abnormality clears up. No potential conflict of interest relevant to this article was reported.

岡山医学会 Acta Medica Okayama 0030-1558 78 1.suppl 1966 過去15年間(昭和25年-昭和39年)の鳥取県下における日本脳炎の流行状況について 日本脳炎の疫学的研究, 第5報 41 49 EN Iwao Teratani Masana Ogata In their epidemiological studies on the epidemic of Japanese B Encephalitis that broke out in Tottori Prefecture during past 15 years (1950-1964), the authors obtained the following results. 1) Every year's morbidity rate except 1954 in Tottori Prefecture was higher than that in all Japan. 2) As for the season of prevalence, the end of August or the beginning of September was a peak of prevalence. 3) In the next year of a high epidemic year, there was tendency that the peak of prevalence expressed as median was later coming than that of the former year. 4) As for the district of prevalence, the morbidity rate of Sakaiminato City is the smallest in Tottori Prefecture during past 15 years. 5) As for the sex, male morbidity rate was higher than female one. 6) Concerning age, rate of morbidity in children below 10 years of age has been decreased, and that in people above 60 years of age has been increased during past 5 years. No potential conflict of interest relevant to this article was reported.

岡山医学会 Acta Medica Okayama 0030-1558 78 1.suppl 1966 岡山県に於ける豚, さぎ, 住民の日本脳炎血球凝集抑制反応値の変動 日本脳炎の疫学的研究, 第4報 31 39 EN Masana Ogata Norihiko Hasegawa Katashi Hitomi Kengo Awaya Iwao Teratani Naoji Kitamura Yutaka Nagao Takeo Takahashi Hiroshi Kondo Tetsuro Kajikiyo Haemoagglutinin inhibition test (HI test) of Japanese B Encephalitis was conducted in the people, pigs and heron that lived in Okayama Prefecture in 1966, and following results were obtained. 1. The first epidemic in the pigs in the year was shown on the middle of June and 20% of the pigs showed positive HI test, 1:160 or above. The second wide epidemic in the pigs was also observed in the begining of August and all of the pigs showed positive HI test. The above results were obtained from the HI test of pigs in the slaughterhouses, and the HI test of serum obtained from the ear veine of pigs in the breeding house also showed similar results. 2. On the HI test of night heron, caught at the nests in the mountain at Tsudaka Village, half of heron showed positive reaction. However HI test of white heron lived in the nests near the nests of night heron, showed negative reaction. 3. On the HI test of inhabitants in Higashiawakura Village, where the patient of Japanese B Encephalitis has not been found, a half of the inhabitants injected Japanese B Encephalitis vaccine showed positive reaction and the non vaccinated group showed negative reaction. 4. The high specific active antibody of HI reaction was prepared from pig γ globulin by DEAE cellulose column çhromatography. No potential conflict of interest relevant to this article was reported.