The Parvoviridae have been of increasing interest to reseachers in the
past decade. Their small size and simple structure have made them ame-
nable to detailed physiochemical analysis, and from this work relatively
detailed information has resulted that has signficantly increased our
un- derstanding of the biology of these viruses. It has become clear
that the Parvoviridae are of interest not only for their own sake, but
also because their relative simplicity renders them useful probes in the
study of the biology of host cells and of other DNA viruses with which
they interact. The Dependovirus genus, for instance, contains the
defective adeno-as- sociated viruses (AA V), which require a coinfection
with either an ad- enovirus or a herpesvirus for productive
multiplication. Studies of AA V, therefore, necessarily impinge on our
understanding of the control of macromolecular synthesis by the helper
virus. Similarly AA V has been reported to inhibit the oncogenicity of
both adeno-and herpesviruses and has been used as a probe of mechanism
in these instances as well. Finally, AA V establishes latent infections
in vivo and is the only mammalian DNA virus where a comparable model
system has been established in cell culture. This system has allowed
study of the mechanism of latent infection at the molecular level.