Fig. 1
From: Characterization of Puerto Rican West Nile Virus isolates in mice
Plaque size for PR isolates compared to its parental strain, NY99. Vero cells were infected for either 3 or 4 days with the WNV and plaque sizes were measured expressed as least square means (LS Means) in inches. ANOVA analysis indicated that the PR isolates had statistically significantly smaller plaques than NY99. (*p = 0.002, **p = 0.0001)