FIG 4.

In vitro growth kinetics for chimeric viruses. Growth kinetics were determined for WNV NY99 and each of the four chimeras following infection of Vero (A) and C6/36 (B) cells in triplicate flasks at a low MOI of 0.0005. Statistical significance was determined by ANOVA with the Bonferroni correction for all viruses by comparison to the results for WNV NY99 (*, P < 0.05; **, P < 0.01; ***, P < 0.001; the different colors correspond to individual chimeras). The graphs show mean values with standard errors.