Rapid quantitation of porcine epidemic diarrhea virus (PEDV) by Virus Counter.

Virus Counter was applied for the quantitation of porcine epidemic diarrhea virus (PEDV); the working range and reproducibility of the quantification were characterized, and the performance of Virus Counter was evaluated using the plaque assay as the gold standard. In this study, the single burst curves of PEDV were first constructed with the Virus Counter or plaque assay respectively, and the results from Virus Counter and plaque assay showed similar high correlation for interval of 12-24 h (r=0.9581, p<0.05). Then three virus batches from independent virus propagations were harvested at interval of 16-20 h and serial-diluted; The correlation between the calculated titer and the results obtained by Virus Counter were better than those obtained by using the plaque assay. The comparison between the plaque assay data and the Virus Counter results revealed a linear relationship (slope=1.155±0.46, R(2)=0.9665) with a significant Pearson correlation (r=0.9809, p<0.0001). The results of this study demonstrated that Virus Counter is a simple and reliable method to quantify the viral particles of PEDV.