Detection and Diagnosis of Viral Infections

Diagnostic tests are paramount in determining the etiology of viral infections. Direct diagnostic methods assay for the presence of the virus, while indirect methods test for effects of the virus. Cell culture is the process of growing cells or tissues in the laboratory. Cell lines can be infected with patient samples to allow viral replication within the cells; observable cytopathic effects can help to identify the identity of the virus. Infected cells can also be used for immunofluorescence assays, which use fluorescently labeled virus-specific antibodies to identify viruses in fixed cells or tissues. A variety of diagnostic immunoassays exist, including enzyme-linked immunosorbent assays/enzyme immunoassays, western blots, lateral flow immunoassays, and agglutination reactions. Assays that detect viral nucleic acids are based upon the principles of PCR or nucleic acid hybridization, are extremely sensitive, and are specific for a particular virus.