Sl no. Time intervals of
Cytopathic effects in CEF from 0 hours PI to 96 hours PI
Field virus isolate BOM–1 isolate
1 0 hour No CPE observed No CPE observed
2 12 hours No CPE observed No CPE observed
3 24 hours Rounding of cells, small cytoplasmic vacuolations Same CPE but more intense and prominent.
4 36 hours Variable sizes of plaques, discrete clumping of cells. Comparatively larger sizes of plaques and cell clumps.
5 48 hours Formation of Syncytia, Number and diameter of plaques increased. Large cell clumps and plaques but no syncytia observed.
6 60 hours Mild coalescence of plaques. Syncytia and coalescence of plaques.
7 72 hours large syncytia observed, Disintegration of cell sheet started. Syncytia formation, Coalescence of plaques, large areas of cell
destruction and disintegration,
8 84 hours Large cell clumps, Disorganization of monolayer. Disorganization of monolayer and Large cell clumps floating on
superficial media.
9 96 hours Absence of cellular morphology and cell organization Detachment of cell sheet from the adhering surface.
Table 2: Comparative observations of CPE in different time intervals in Chick embryo fibroblast monolayers infected with Field Virus isolate and BOM-I isolate.