Cytopathic effect

Cytopathic effect (abbreviated CPE) refers to structural changes in host cells that are caused by viral invasion.

Many CPEs can be seen in unfixed, unstained cells under the low power of an optical microscope, with the condenser down and the iris diaphragm partly closed.

[2] Some viruses' CPEs are characteristic and therefore can be an important tool for virologists in diagnosing an infected animal or human.

If CPE appears after 4 to 5 days in vitro at low multiplicity of infection, then the virus is considered slow.

If the CPE appears after 1 to 2 days in vitro at low multiplicity of infection, then the virus is thought to be rapid.

The inclusion bodies can first be identified by light microscopy in patient blood smears or stained sections of infected tissues.

Inclusion bodies may either be accumulation of virus replication byproducts or altered host cell organelles or structures.

An assay has been developed that screens the dengue virus's CPEs in order to assess cell viability.

[5] Due to the host cell specificity of CPEs, researchers can also use them to test any discrepancies in an experiment.

All cells in the monolayer shrink rapidly, become dense in a process known as pyknosis, and detach from the glass within three days.

Similarly to total destruction, this CPE is observed by seeding a confluent monolayer of host cell on a glass surface then introducing a viral infection.

Although this type of CPE may eventually affect the entire tissue, the initial stages and spreading occur at localized viral centers known as foci.

Focal degeneration is due to direct cell-to-cell transfer of the virus rather than diffusion through the extracellular medium.

This different mode of transfer differentiates it from total and subtotal destruction and causes the characteristic localized effects.

Typically, they indicate the areas of the host cell where viral protein or nucleic acid is being synthesized or where virions are being assembled.