parvoviruses

Parvoviruses are a family of small, nonenveloped, icosahedral viruses with linear, single-stranded DNA genomes. Their genomes are about 4 to 6 kilobases long and encode two main transcriptional units: nonstructural NS proteins and structural capsid proteins VP1/VP2. Virions are among the smallest DNA viruses and replicate in the host cell nucleus. Productive infection generally requires host cells to be in the S phase of the cell cycle. Some members, particularly those in the genus Dependoparvovirus, require a helper virus for replication.

Taxonomy and notable members: Parvoviridae comprises several genera, including Parvovirus (autonomous parvoviruses of animals such as canine parvovirus and feline panleukopenia virus), Dependoparvovirus (adeno-associated viruses, AAV), Erythroparvovirus (human parvovirus B19), and Bocaparvovirus (which includes several human and animal respiratory pathogens). AAVs are widely studied as gene therapy vectors due to their relatively low pathogenicity and ability to target diverse tissues.

Pathogenesis and disease: In animals, parvoviruses often cause gastrointestinal disease and can be particularly severe in young animals with immature immune systems. Canine parvovirus causes acute gastroenteritis; feline panleukopenia virus leads to leukopenia and enteritis. In humans, parvovirus B19 causes erythema infectiosum (slapped-cheek rash) and can cause aplastic crises in individuals with hemolytic disorders or fetal valve abnormalities. Transmission routes vary by virus but commonly include fecal–oral and respiratory pathways.

Diagnosis, prevention, and control: laboratory diagnosis relies on PCR detection of viral DNA and serology. Vaccination programs exist for dogs and cats, substantially reducing disease burden. Human infections are typically self-limited, though pregnant women and immunocompromised individuals may experience complications. Parvoviruses such as AAV are exploited as gene therapy vectors due to their safety profile and tissue tropism.