Development of a chromatographic strip assay for detection of porcine antibodies to 3ABC non-structural protein of foot-and-mouth disease virus serotype O.

A chromatographic strip assay was developed for rapid detection of serum antibodies to non-structural protein of foot-and-mouth disease virus. The assay was based on Escherichia coli-expressed 3ABC non-structural protein and an immunochromatographic technique, which shortened the detection time to about one hour. The sensitivity of the assay was determined to be 96.8% for infected pigs; its specificity was 100% for naïve pigs and 98.8% for vaccinated pigs. In the experimentally infected pigs, anti-3ABC antibodies were detectable from eight days post-infection until the end of the study, 34 days post-infection. The performance of this assay was comparable to that of two commercial ELISA kits, Ceditest FMDV-NS and UBI FMDV NS EIA, and was better than that of CHEKIT FMD-3ABC po. Given its advantages of instant testing and quantitative measurement, this assay has potential as a useful tool for rapid on-farm diagnosis of foot-and-mouth disease.