Development and preliminary application of an immunochromatographic strip for rapid detection of infection with porcine reproductive and respiratory syndrome virus in swine.

A "strip test" to detect porcine reproductive and respiratory syndrome virus (PRRSV) was established using a monoclonal antibody (MAb) 2D7 conjugated with colloidal gold. Two MAbs binding to protein N at different epitopes, 2D7 and 1G7 were obtained. In the test, samples of PRRSV bound to colloidal gold-conjugated MAb 2D7. The complex was then captured by MAb 1G7 at the test line (T) on the nitrocellulose membrane, presenting a purple band. If the sample did not contain PRRSV or if the quantity of PRRSV was less than that required for the kit, only the control line (C), in which goat anti-mouse antibody was added as the capture antibody, was present. Results from the sensitivity test of the kit demonstrated that the lowest detected quantity of PRRSV is 2.9 × 10(3)TCID(50)/ml. In clinical trials, the specificity and the sensitivity of this kit are 98.1% and 88.4%, respectively, compared with RT-PCR. Furthermore, this kit was found to be efficient in three areas of China and appears to have better results in practical applications than in empirical studies. In summary, this kit has not only high rates of specificity and sensitivity but also has the beneficial features such as efficiency, convenience and speed.