ABSTRACT
The most important members of the Orthomyxoviridae family are influenza virus types A and B which have been given the generic status of Influenza. Viruses of freshly isolated strains of Influenza are often heterogeneous in size and shape. Filamentous forms sectioned in various planes are usually seen in thin sectioned preparations. Neuraminidase hydrolyzes neuraminic acid residues from mucoproteins and allows virus to elute from cell receptors. Influenza C virus, which has not been given the status of a genus of the Orthomyxoviridae family, may appear to be identical in morpology to Influenza A or B, or may be stained so that a hexagonal structure of the virus surface is clearly evident. The RNA-dependent RNA polymerase within the particle transcribes viral RNA segments into mRNAs. Nucleocapsid protein is synthesized in the cytoplasm and is probably transported to the nucleus to form nucleocapsids.
