Epidemiological study on viral zoonotic diseases originating from wild rodents in Japan

为了解日本肾综合征出血热(HFRS)、森林脑炎(TBE)等人畜共患病的流行情况，我们在日本各地进行了流行病学调查。在姬鼠体内检出抗汉坦病毒抗体。用间接荧光抗体试验(IFA)检测了大鼠(5/482)、红纹伊蚊(7/197)、褐家鼠(4/364)和家鼠(3/45)。该阳性血清对汉滩病毒的中和效价为1：20，但不能中和汉城病毒。由此可见，华支睾吸虫携带的汉坦病毒比汉城病毒更接近汉滩病毒。从血清阳性的田鼠中扩增出S基因的部分片段，并进行了序列测定。该病毒序列与首尔病毒原型株SR-11有96%的同源性。这些结果表明，日本汉坦病毒的主要宿主动物是大仓鼠、红纹伊蚊、褐家鼠和响尾鼠。用重组的TBE病毒E蛋白检测抗-TBE病毒抗体，将啮齿动物血清应用于新建立的ELISA。中和试验阳性血清中可检出抗-TBE抗体。然而，在富山县的啮齿动物血清中没有检测到抗体，这其中的TBE感染尚未得到证实。这些结果表明，酶联免疫吸附试验可作为确定日本TBE流行区的一种有效方法。

To know the epidemiology of viral zoonotic diseases such as hemorrhagic fever with renal syndrome (HFRS) and tick-borne encephalitis (TBE) in Japan, we conducted an epizootiological survey in various points of Japan. Anti-hantavirus antibodies were detected in Apodemus. speciosus (5/482), and Clethnonomys rufocanus (7/197), Rattus norvegicus (4/364), and Rattus rattus (3/45) by Indirect fluorescent antibody assay (IFA). The positive sera from A.speciosus neutralized Hantaan virus at 1:20 but did not neutralize Seoul virus. This indicate that hantavirus carried by A.speciosus is closer to Hantaan virus than Seoul virus. The partial S gene was amplified from seropositive R.rattus and sequenced. The virus sequence had 96% identitiy with SR-11 which is Seoul virus prototype strain. These results suggest that main reservoir animals of hantavirus in Japan are A.speciosus, C. rufocanus, R.norvegicus, and R rattus.The rodent sera were applied to the newly established ELISA by using recombinant E protein of TBE virus to detected anti-TBE virus antibodies. The ELISA could detect anti-TBE antibodies in sera positive by neutralization test. However, no antibodies were detected in rodent sera from Toyama prefecture, in which TBE infections has not confirmed. These results suggest that the ELISA can be a useful method to identify the endemic areas of TBE in Japan.