The use of shell vial fluid to facilitate early detection and serotyping of influenza viruses

The use of Madin-Darby canine kidney cells (MDCK) in a shell vial system for the rapid detection of influenza viruses has been well established1, 2. Generally, at the end of the incubation period, the fluid (medium) inside the shell vial tube is discarded and the coverslip is rinsed with PBS and then subjected to an immunofluorescence (IMF) test, using anti influenza virus antibodies. A positive fluorescence test will indicate the presence of an influenza virus in the specimen. This technique, however, does not determine the subtype of the influenza virus. To determine the influenza virus subtype, one still needs the use of embryonated eggs. In this report we describe the successful use of the fluid in the shell vial tube at the end of the incubation period, to detect and subtype influenza viruses. With this approach, there is no need for the use of embryonated eggs and the final result, including the identity of the influenza virus subtype, is obtainable within 48 hours.