Spiraviridae
Spiraviridae is a family of incertae sedis viruses that infect hyperthermophilic archaea, specifically Aeropyrum pernix. The family comprises a single genus, Alphaspiravirus, and species, Aeropyrum coil-shaped virus (ACV). The non-enveloped virions are hollow cylinders formed by a coiled fiber, with each end of the cylindrical capsid featuring a protruding appendage. The viral genome is single-stranded positive-sense DNA (ssDNA+) and encodes significantly more genes compared to other ssDNA viruses. Uniquely, ACV lacks its own replication enzymes and relies on the host cell’s replisome machinery for genome replication. Although unrelated to other archaea-infecting viruses, its coiled morphology links it to a potential ancient lineage of archaeal viruses.
