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NAOSITE : Nagasaki University's Academic Output SITE > Institute of Tropical Medicine > Bulletin > Tropical medicine > Volume 17, No. 3 >

日本における日本脳炎ウイルスの生態学 : II.伝搬蚊の個体群と日本脳炎の流行

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Title: 日本における日本脳炎ウイルスの生態学 : II.伝搬蚊の個体群と日本脳炎の流行
Other Titles: Ecology of Japanese Encephalitis Virus in Japan : II. The population of vector mosquitoes and the epidemic of Japanese encephalitis
Authors: 和田, 義人 / 小田, 力 / 茂木, 幹義 / 森, 章夫 / 林, 薫 / 三舟, 求真人 / 七条, 明久 / 松尾, 幸子
Authors (alternative): Wada, Yoshito / Oda, Tsutomu / Mogi, Motoyoshi / Mori, Akio / Hayashi, Kaoru / Mifune, Kumato / Shichijo, Akehisa / Matsuo, Sachiko / Omori, Nanzaburo / Fukumi, Hideo
Issue Date: 30-Jan-1976
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 17(3). p111-127, 1976
Abstract: 1964年から1973年の間に長崎地方で得られた資料を用いて,伝搬蚊コガタアカイエカの個体群と日本脳炎の流行との関係を吟味した.その結果次の諸点が明らかとなった.(1)各年のコゴタアカイエカの越冬雌成虫及び新生雄成虫の出現開始時期と,日本脳炎の流行が始まる時期との間には関係は認められなかった.(2)日本脳炎の流行の開始は,一般にはコガタアカイエカ個体群の密度の上昇と一致していた.(3)日本脳炎患者の発生数が多い年には,コガタアカイエカの1年を通じての累積密度は一般に高かった.しかし,伝搬蚊の累積密度がある特定の値より低い年には,極めてわずかの患者しか発生しなかった.この累積密度の特定の値は,おそらく豚で日本脳炎が流行するための伝搬蚊の限界密度と関連したもののように思われる.(4)日本脳炎患者数は,豚で流行が起っている時期の伝搬蚊の密度と明らかに比例関係にあることがわかった.(5)日本脳炎ウイルスによるコガタアカイエカの感染率は年によって違いがあるが,日本脳炎の流行の規模とは無関係であった.(6)越冬からさめたばかりのコガタアカイエカ雌成虫は何れも未経産であったので,越冬コガタアカイエカの体内で日本脳炎ウイルスが越冬する可能性はまず無いと考えられた.(7)近年におけるコガタアカイエカの密度の低下は,患者の発生数の減少をもたらした最も重要な要因の1つと考えられた. / The relation between the population of the vector mosquito, Culex tritaeniorhynchus, and the epidemic of Japanese encephalitis (JE) was analyzed with the data obtained in the Nagasaki district during ten years from 1964 to 1973. The results revealed the following points. (1) The starting time of the appearance of overwintered females or newly-emerged males of tritaeniorhynchus in each year has no relation to the starting time of JE epidemic as represented by the first isolation of JE virus from tritaeniorhynchus or the first appearance of 2-ME sensitive antibody in slaughtered pigs. (2) The start of JE epidemic coincided generally with the rise in the population density of tritaeniorhynchus. (3) In the year when the number of JE human cases was large, the accumulated density of tritaeniorhynchus throughout the year was generally high. However, only a very few cases appeared in years when the accumulated density of the vector mosquito was lower than a certain critical value which is probably related to the threshold density of vectors for the occurrence of JE epizootic in pigs. (4) It was clearly demonstrated that the number of human cases is directly proportional to the vector density when the pig epizootic is in progress. (5) The infection rate of tritaeniorhynchus with JE virus was variable in years, but apparently had no relation to the size of JE epidemic. (6) It was concluded that the possibility for overwintering tritaeniorhynchus females to have JE virus in their bodies is, if ever, extremely low, because no females just having emerged from hibernation were found parous. (7) The lowering density of tritaeniorhynchus in recent years was considered to be one of the most important factors to have induced the reduction of the number of human cases.
URI: http://hdl.handle.net/10069/4185
ISSN: 03855643
Type: Departmental Bulletin Paper
Appears in Collections:Volume 17, No. 3

Citable URI : http://hdl.handle.net/10069/4185

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