Parvovirinae

Parvovirinae is a subfamily of the Parvoviridae family comprising small, non-enveloped, icosahedral viruses with linear single-stranded DNA genomes. They infect vertebrates, including mammals, birds, and reptiles. Genomes are typically 4 to 6 kilobases and encode two main transcription units: a non-structural set (NS1/NS2) involved in replication and regulation, and a structural set (VP1/VP2) that forms the virion, with additional proteins produced by alternative splicing in some genera.

Replication occurs in the host cell nucleus and relies on host DNA polymerase, usually in S phase. Parvoviruses use a rolling hairpin mechanism for genome replication. Autonomous parvoviruses replicate independently, whereas dependoparvoviruses require a helper virus such as adenovirus or herpesvirus; adeno-associated viruses are common dependoparvoviruses used as gene therapy vectors.

Taxonomically, Parvovirinae comprises several genera, including Parvovirus, Dependoparvovirus, Protoparvovirus, Bocaparvovirus, Copiparvovirus, Tetraparvovirus, Erythroparvovirus, Amdoparvovirus, and Aveparvovirus. Notable members are human parvovirus B19 (Erythroparvovirus), canine parvovirus and feline panleukopenia virus (Protoparvovirus), and adeno-associated viruses (Dependoparvovirus).

Pathogenesis varies by host and virus. In humans, B19V injures erythroid precursors in the bone marrow, potentially causing aplastic crises and fetal anemia with hydrops fetalis in pregnancy. In animals, parvoviruses commonly cause acute gastroenteritis and panleukopenia, especially in puppies and kittens. Transmission is typically fecal-oral or respiratory, with environmental stability enabling spread. Vaccines exist for several veterinary parvoviruses; no broadly used human vaccine targets B19V. In biotechnology, AAV vectors are widely used for gene therapy due to their safety profile and capacity for long-term expression, though replication requires helper functions.