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Ecological Studies on Japanese Encephalitis Virus Survey of virus dissemination in Nagasaki area, Japan, in 1966 and 1967

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Title: Ecological Studies on Japanese Encephalitis Virus Survey of virus dissemination in Nagasaki area, Japan, in 1966 and 1967
Other Titles: 日本脳炎ウイルスの生態学的研究1966年及び1967年の野外調査成績
Authors: Shichijo, Akehisa / Mifune, Kumato / Hayashi, Kaoru / Wada, Yoshito / Ito, Sumiyo / Kawai, Senji / Miyagi, Ichiro / Oda, Tsutomu
Authors (alternative): 七条, 明久 / 三舟, 求真人 / 林, 薫 / 和田, 義人 / 伊藤, 寿美代 / 河合, 潜二 / 宮城, 一郎 / 小田, 力
Issue Date: 20-Nov-1968
Publisher: 長崎大学熱帯医学研究所 / Institute of Tropical Medicine, Nagasaki University
Citation: 熱帯医学 Tropical medicine 10(3). p168-180, 1968
Abstract: Serial survey on the ecology of Japanese encephalitis (JE) virus was made in 1966 and 1967. In spring in the both years, wild caught females of Culex tritaeniorhynchus and many other species including a great number of hibernated females were examined for JE virus. In 1967, besides the above, wild caught females in spring were forced to engorge blood from susceptible pigs, and some days after, the engorged ones were examined for the virus and the pigs for HI antibody. However, no virus was found in all the mosquitoes examined, and no antibody was detected in the pigs. Nevertheless, in mid-spring in 1967 2-ME sensitive antibody was found in a few of slaughtered pigs. This facts is very important and it seems necessary to set forward the program of investigations. Japanese common snakes of six species were examined for the reservoir of JE virus in nature, but it was concluded that snakes play minor role as a natural source of the virus transmission even in the epidemic season. Despite of the fact that the starting time of epizootic in pigs and of the occurrence of infected mosquitoes was nearly the same in 1966 and 1967, the duration and size of the infection in mosquitoes and of the epidemic in men were shorter and smaller in 1967 than in the previous year. The reason seems that the larger number of infected mosquitoes at the starting time in late June,1967 caused earlier and more rapid rise in the HI antibody possessing rate of pigs at the early days of epizootic in them reducing the remaining rate of susceptible pigs as faster as about a half-month than in 1966, and this, in turn, caused subsequent infections in mosquitoes and then in men to be shorter in duration and smaller in size. / 前年に引き続き,1966年及び1967年に日本脳炎ウイルスの生態学的調査を行つた.両年の春,野外で採集した,多数の越年雌成虫を含むコガタアカイエカ及び他の数種の蚊からのウイルス分離を試みた.更に1967年の春には,野外採集蚊を感受性豚から吸血させ,数日後に吸血蚊からはウイルス分離を,吸血された豚からはウイルス分離とHI抗体の検出を試みた,しかし,上記の何れの蚊からもウイルスは発見されず,何れの豚からも抗体は認められなかつた.それにも拘らず1967年の春には少数のと場豚から2-ME感受性抗体が検出された.この事実は注目に値し,今後この方面からの研究が必要である.野外で採集した6種の蛇について調査した結果,蛇は日本脳炎ウイルスの伝搬源としては,日本脳炎の流行期においても,重要な役割を果していないものと結論される.豚における日本脳炎ウイルスの汚染及び感染蚊出現の開始時期は1966年と1967年とで殆んど同じであつたが,蚊における感染及び人における流行の期間と大きさは1966年には1967年におけるよりも長く,かつ大きかつた.従つて,これは1967年におけるように,流行の開始時期に感染蚊が多く,豚における汚染の上昇が前年に比較して半月ほど早く,かつ急激であつた.このことが感受性豚を少なくし,従って蚊における感染及び人における感染を短かく,そして小さくしたものと思われる.
URI: http://hdl.handle.net/10069/4039
ISSN: 03855643
Type: Departmental Bulletin Paper
Appears in Collections:Volume 10, No. 3

Citable URI : http://hdl.handle.net/10069/4039

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