The fine structure of foamy virus

Abstract

Paramyxoviridae are enveloped viruses with a helical nucleocapsid containing an unsegmented single-stranded RNA genome of negative polarity. They replicate in the cytoplasm of infected cells. Cytopathic effects differ with members of the group and host cell, ranging from extensive cell-cell fusion in some systems, cell rounding, and stelliform appearance in others, to a total lack of overt cytopathic effect in spite of massive and continued virus production. Paramyxoviruses contain a hemagglutinin and neuraminidase activity. They share this feature with myxoviruses. Paramyxoviridae are pathogens that cause respiratory diseases in man (parainfluenza virus types 1 to 4, mumps virus), other mammals—for example, the mouse (Sendai virus), and birds (e.g. Newcastle disease virus). Most of the knowledge regarding the paramyxovirus virion is based on studies of a few members of this large group of viruses—that is, parainfluenza virus type 1 (Sendai virus), simian virus type 5 (SV5) and Newcastle disease virus (NDV). This chapter focuses on parainfluenza virus type 1 (Sendai virus), together with findings made with related viruses.