Improvement of indirect enzyme-linked immunosorbent assay for detection of Japanese encephalitis virus antibodies in swine sera |
Dong-Kun Yang1, Ha-Hyun Kim1, Hyun-Ye Jo1, Seung Heon Lee1, Sang-Ho Jang2, Sang-Oh Lee2, Sung-Suk Choi1, In-Soo Cho1 |
1Viral Disease Division,Animal and Plant Quarantine Agency 2R&D Center, MEDIAN Diagnostics |
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Abstract |
Japanese encephalitis (JE) is an important zoonosis caused by the mosquito-transmitted JE virus (JEV), which is a causative agent of reproductive failure in pregnant sows. Detection of JEV antibodies in swine is performed by hemagglutination inhibition (HI), virus neutralization (VN), and the plaque reduction neutralization test (PRNT). The most stringent PRNT is the 90% endpoint PRNT ($PRNT_{90}$). These conventional assays are difficult to carry out in diagnostic laboratories with insufficient instruments or cell culture systems. An alternative assay that is easily conducted and time efficient is required. In this study, we improved the indirect enzyme-linked immunosorbent assay (I-ELISA) with clarified antigen for the detection of JEV antibodies. The I-ELISA results obtained from 175 swine serum samples were compared with HI, VN, and $PRNT_{90}$ results. The sensitivity of I-ELISA was 91.8%, 95.0%, and 94.7% compared with HI, VN, and $PRNT_{90}$ results, respectively. The specificity of I-ELISA was 92.2%, 94.7%, and 94.7% compared with HI, VN, and $PRNT_{90}$ results, respectively. Moreover, the I-ELISA results were significantly correlated with the HI (r = 0.93), VN (r = 0.95), and $PRNT_{90}$ (r = 0.92) results. These results suggest that the improved I-ELISA is useful for serosurveillance of JEV in swine. |
Key Words:
Japanese encephalitis virus, indirect enzyme-linked immunosorbent assay, surveillance, swine |
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