Development of a convenient immunochromatographic strip for the diagnosis of infection with Japanese encephalitis virus in swine.

Japanese encephalitis (JE) is caused by the Japanese encephalitis virus (JEV). It is a major public health problem in Asia. JEV infects swine which results in fatal encephalitis, abortion and stillbirth in pregnant sow, and hypospermia in boars. Swine is a viral amplifier, and thus plays a critical role in JEV transmission. Thus, development of a rapid method for JEV detection in swine is required for clinical JE diagnosis, as well as to suppress viral spread. In this study, a convenient and rapid immunochromatographic strip (ICS) was developed for detecting JEV in swine using two monoclonal antibodies (MAbs) (2A2 and 4D1) against the E protein of JEV. Results showed that colloidal gold-conjugated MAbs 2A2 (CG-MAb) bond with JEV and the resulting complex was held by the other MAb 4D1 at the test line to give a reddish-purple band. Sensitivity tests demonstrated that ICS can detect 2.5x10(5)PFU of JEV. The clinical screening results showed that the specificity and sensitivity of the ICS were 99.3% and 85.7% respectively as compared to that of RT-PCR. This suggests that the MAbs-based ICS test can be used as a convenient method for the rapid detection of JEV in infected swine samples.