Tadano M, Kanemura K, Hasegawa H, Makino Y, Fukunaga T
Department of Virology, Faculty of Medicine, University of the Ryukyus, Okinawa, Japan.
Microbiol Immunol. 1994;38(2):117-22. doi: 10.1111/j.1348-0421.1994.tb01752.x.
From 1985 to 1989, serum specimens of swine raised in the northern, central and southern areas in Okinawa island were examined for Japanese encephalitis (JE) virus antibody by ELISA and hemagglutination-inhibition test. The antibody positive rate was found to be higher in the north and central than in the south. The 2-mercaptoethanol sensitive antibody to JE was detected mostly in June and July, and occasionally in other months except February and March. There was no month when all specimens from three areas turned antibody-negative simultaneously, indicating that JE virus transmission to swine lasted longer in Okinawa island than in other temperature areas in Japan. From 1986 to 1991, the vector mosquitoes (Culex tritaeniorhynchus) were collected in a pig farm in the south of Okinawa island. A total of 153 strains of JE virus was isolated from the vector mosquitoes mainly in June. In Miyako and Ishigaki islands, the antibody positive rate in swine sera was found to be extremely low, compared with that in Okinawa island. In Miyako island, where no paddy rice field is cultivated, a few adults as well as larvae of the vector mosquito were collected, while in Ishigaki island, where there are many watered rice fields, a lot of adults as well as larvae were collected. Although the environmental situation is quite different between the two islands, JE virus transmission appeared to be very low in both islands.
1985年至1989年期间，采用酶联免疫吸附测定法（ELISA）和血凝抑制试验，对在冲绳岛北部、中部和南部饲养的猪的血清样本进行了日本脑炎（乙脑）病毒抗体检测。结果发现，北部和中部地区的抗体阳性率高于南部地区。乙脑的2-巯基乙醇敏感抗体大多在6月和7月检测到，除2月和3月外，其他月份偶尔也能检测到。没有一个月三个地区的所有样本同时呈抗体阴性，这表明乙脑病毒在冲绳岛传播给猪的时间比日本其他温带地区更长。1986年至1991年期间，在冲绳岛南部的一个养猪场收集了媒介蚊虫（三带喙库蚊）。从媒介蚊虫中分离出了总共153株乙脑病毒，主要是在6月。与冲绳岛相比，宫古岛和石垣岛猪血清中的抗体阳性率极低。在没有稻田的宫古岛，收集到了几只媒介蚊虫的成虫和幼虫，而在有许多灌溉稻田的石垣岛，收集到了大量的成虫和幼虫。尽管两个岛屿的环境状况差异很大，但乙脑病毒在两个岛屿的传播似乎都非常低。
