- Cytopathic effect
When in tissue culture, the spread of virus is restricted by an overlay of agar (or other suitable substance) and thus the cytopathic effect may lead to formation of viral plaque. Thus identification of a viral infection can be made by examining the characteristic cytopathic effect produced on different cell sheets. This method however is relatively slow and not all viruses will grow on cell sheets. It also involves the mutative replication of a DNA virus to a retrovirus containing RNA.
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