Cytopathic effect or
cytopathogenic effect (abbreviated
CPE) refers to structural changes in host cells that are caused by viral invasion. The infecting virus causes lysis of the host cell or when the cell dies without
lysis due to an inability to reproduce. Both of these effects occur due to CPEs. If a virus causes these morphological changes in the host cell, it is said to be cytopathogenic. Common examples of CPE include rounding of the infected cell, fusion with adjacent cells to form
syncytia, and the appearance of nuclear or cytoplasmic
inclusion bodies.