1. Cytopathic effects (CPE)
Morphological changes occurring in cells due to viral infection is called cytopathic effects.
The virus responsible are called cytopathogenic virus.
CPE depends on various factors
Some viruses cause very little or no CPE in cells of their natural host but can be detected via
Inhibition of replication of another virus
Or presence of viral genome or antigens in cultured cells

2. Cell Death

3. Swelling and Clumping
Adenovirus infected cells greatly enlarge and clump together in” grape-like” clusters.
Cytomegalovirus infected cells swell and round up

4. Vacuolization
Cytoplasmic vacuoles characteristic of polyoma virus

5. Cell fusion
RSV infection induces fusion with adjacent cells to form a syncytia (polykaryocytes)

6. Inclusion Bodies RSV cytoplasmic inclusions Adenovirus
nuclear inclusions
Rabies virus
cytoplasmic inclusions
Negri bodies