Naldaviricetes is a class of viruses, which infect arthropods. Members of Naldaviricetes are characterized by large enveloped rod-shaped virions, circular double-stranded DNA genomes, and replication in the nucleus of the host cell. All of them (including the unassigned Polydnaviridae family) share a set of unique genes not found in other viruses, which include the presence of multiple interspersed direct repeats, various subunits of DNA polymerase and RNA polymerase, four late expression factor genes, and infectivity factor genes suggesting a common host entry mechanism.