Polymerase chain reaction (PCR) is an approach allowing identification of virus-specific nucleic acids (DNA or RNA). The method is based on the use of sequence-specific primers that bind to viral DNA. If the viral nucleic acid is present in the sample, it will be amplified confirming viral infection.
The enzyme-linked immunosorbent assay (ELISA) is an approach allowing identification of viruses or virus proteins using specific antibodies. The binding of antibodies to virus proteins is detected using an enzymatic reaction associated with the change of colour confirming the presence of the viral infection.