RESEARCH ARTICLE A Novel Immunochromatographic Test Applied to a Serological Survey of Japanese Encephalitis Virus on Pig Farms in Korea

Among vertebrate species, pigs are a major amplifying host of Japanese encephalitis virus (JEV) and measuring their seroconversion is a reliable indicator of virus activity. Traditional-ly, the hemagglutination inhibition test has been used for serological testing in pigs; howev-er, it has several limitations and, thus, a more efficient and reliable replacement test is required. In this study, we developed a new immunochromatographic test for detecting anti-bodies to JEV in pig serum within 15 min. Specifically, the domain III region of the JEV enve-lope protein was successfully expressed in soluble form and used for developing the immunochromatographic test. The test was then applied to the surveillance of Japanese en-cephalitis (JE) in Korea. We found that our immunochromatographic test had good sensitivi-ty (84.8%) and specificity (97.7%) when compared with an immunofluorescence assay used as a reference test. During the surveillance of JE in Korea in 2012, the new immuno-chromatographic test was used to test the sera of 1,926 slaughtered pigs from eight prov-inces, and 228 pigs (11.8%) were found to be JEV-positive. Based on these results, we also produced an activity map of JEV, which marked the locations of pig farms in Korea that test-ed positive for the virus. Thus, the immunochromatographic test reported here provides a convenient and effective tool for real-time monitoring of JEV activity in pigs