FIG. 1.

Plaque phenotypes. The indicated viruses were plated on monolayers of BS-C-1 cells. After 3 days, plaques were imaged using light and fluorescence microscopy and then stained with crystal violet. Areas of at least 140 individual plaques for each of the five viruses were determined, and the averages and standard deviations (in parentheses) were calculated. BF, bright field.