Viruses are obligate intracellular parasites that require living cells in order to replicate. Cell culture for propagation and identification of viruses is an important component of the clinical virology laboratory. In general, diagnostic tests can be grouped into three categories: direct detection, virus isolation and serology. Direct examination methods can usually give a result either within the same or the next day. Immunofluorescence is widely used for the rapid diagnosis of virus infections by detection of virus antigen in clinical specimens and detection of virus-specific antibodies.