Laboratory of Veterinary Microbiology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan.
J Virol Methods. 2013 Jan;187(1):85-9. doi: 10.1016/j.jviromet.2012.09.022. Epub 2012 Oct 6.
Japanese encephalitis virus (JEV) causes serious acute encephalitis in humans and horses. Although dogs are good sentinels for assessing the risk of JEV infection to humans, a virus neutralization test has been the only method available for measuring the levels of JEV antibody in dogs. In this study, an indirect enzyme-linked immunosorbent assay (ELISA) using purified viral particles as an antigen, was developed for serological survey of JEV infection in dogs. In dogs inoculated experimentally with JEV, the ELISA detected anti-JEV IgM 3 days after infection, with IgM levels peaking 7 days after infection. Anti-JEV IgG was detected 14 days after infection and peaked on 21-28 days after infection. Virus neutralization titers correlated with anti-JEV immunoglobulins measured by the ELISA. To test the utility of the new assay, the seroprevalence of JEV infection among 102 dogs in Kyushu, Japan, was examined by IgG ELISA and by virus neutralization. The correlation coefficient between the IgG ELISA and virus neutralization was 0.813 (p<0.001); comparison of the IgG ELISA and virus neutralization showed a sensitivity and specificity of 82% and 98%, respectively. The IgG ELISA was used to survey dogs in Bangkok, Thailand and 51% of these dogs were found seropositive for JEV. These data suggest that in the capital city of Thailand, the risk of infection with JEV remains high.
日本脑炎病毒（JEV）可引起人类和马的严重急性脑炎。虽然狗是评估 JEV 感染人类风险的良好哨兵，但病毒中和试验一直是测量狗体内 JEV 抗体水平的唯一方法。在这项研究中，开发了一种间接酶联免疫吸附试验（ELISA），使用纯化的病毒颗粒作为抗原，用于狗的 JEV 感染血清学调查。在实验感染 JEV 的狗中，ELISA 可在感染后 3 天检测到抗 JEV IgM，感染后 7 天 IgM 水平达到峰值。感染后 14 天检测到抗 JEV IgG，并在感染后 21-28 天达到峰值。病毒中和滴度与 ELISA 测量的抗 JEV 免疫球蛋白相关。为了测试新检测方法的实用性，通过 IgG ELISA 和病毒中和试验检测了日本九州的 102 只狗中的 JEV 感染血清流行率。IgG ELISA 和病毒中和之间的相关系数为 0.813（p<0.001）；比较 IgG ELISA 和病毒中和显示出 82%的敏感性和 98%的特异性。使用 IgG ELISA 对泰国曼谷的狗进行了调查，其中 51%的狗对 JEV 呈血清阳性。这些数据表明，在泰国首都，感染 JEV 的风险仍然很高。
