parvoviridae

Parvoviridae is a family of small, non-enveloped viruses with icosahedral capsids and linear single-stranded DNA genomes about 4 to 6 kilobases in length. Virions are typically 18 to 26 nanometers in diameter. The family is divided into two subfamilies: Parvovirinae, which infect vertebrates, and Densovirinae, which infect invertebrates. Members of Parvovirinae include human pathogens such as parvovirus B19 and the genus Dependoparvovirus, which includes adeno-associated virus (AAV), a widely used gene therapy vector. Densovirinae encompasses parvoviruses that infect insects and other invertebrates.

Genome organization and replication occur in the nucleus. Parvoviruses have a single-stranded DNA genome that must be converted to a double-stranded form before transcription and replication. Replication proceeds via a hairpin-driven mechanism and relies on host cell DNA polymerases; as a result, autonomous parvoviruses preferentially replicate in actively dividing cells that provide the necessary DNA synthesis machinery. Dependoparvoviruses, such as AAV, require a helper virus (for example, an adenovirus or herpesvirus) to provide replication functions.

Hosts, diseases, and distribution vary across genera. In humans, parvovirus B19 causes erythema infectiosum (fifth disease) and can induce aplastic crises in individuals with hemolytic disorders or hydrops fetalis during pregnancy. Canine parvovirus and feline panleukopenia virus cause severe gastroenteritis in young animals. Densovirinae infect invertebrates, including insects, and have been explored for biological control. AAV vectors are notable for research and therapeutic applications, illustrating the clinical and biotechnological relevance of the family.

Diagnosis and research rely on serology, PCR, and virus isolation in specialized laboratories. The Parvoviridae family remains of interest for its simple genome, unique replication strategies, and broad implications in medicine and biotechnology.