Establishment and Application of Plaque Assay for the Detection of West Nile Virus

Objective To establish plaque assay for the quantitative detection of West Nile virus(WNV). Methods Vero cell was selected to be infected with WNV. Approximately 24 h before beginning the titration protocol, Vero cells were plated in 6-well plates to form an even monolayer. Virus in specimens was serially diluted and added to each well to infect the cells. The plates were covered with agarose overlay medium and incubated in an incubator. The plates were stained by a solution of Neutral red, and the number of plaques was counted. Results The plaques appeared as clear circles( 1-3 mm) against a red or pink background. The quantity of virus in infected mouse brain tissues was 10~7 pfu. Conclusion The plaque assay is confirmed as an efficient and rapid protocol of quantitatively detecting WNV in experimentally infected mosquitoes and Leghorn chicken.