parvovirus

Parvovirus refers to a group of small, non-enveloped DNA viruses in the Parvoviridae family. The most clinically important member for humans is parvovirus B19, while canine parvovirus and feline panleukopenia virus are notable veterinary pathogens. Parvoviruses are highly stable in the environment and have a compact genome, typically linear single-stranded DNA about 5 kilobases in length. The virion is icosahedral and measures roughly 18 to 26 nanometers in diameter.

Parvovirus replication requires the host cell to be in the S phase, since the viral genome relies on host cellular machinery. After entry, replication occurs in the nucleus. Parvovirus B19 shows a preference for erythroid precursor cells in the bone marrow, which can lead to reduced red cell production and anemia in susceptible individuals.

In humans, parvovirus B19 infection commonly presents as erythema infectiosum (fifth disease) in children, characterized by a “slapped-cheek” facial rash and mild constitutional symptoms. Adults may experience arthralgias. In individuals with hemolytic disorders, infection can trigger an aplastic crisis. If a pregnant woman becomes infected, the virus can cross the placenta and cause fetal anemia, hydrops fetalis, or fetal loss.

Diagnosis typically uses serology to detect IgM or IgG antibodies and molecular methods such as PCR to detect viral DNA. Blood counts may show transient reticulocytopenia during acute infection. Most infections are self-limited and managed with supportive care; chronic or severe disease in immunocompromised patients may be treated with intravenous immunoglobulin.

There is no licensed vaccine for parvovirus B19 in humans. Vaccines exist for animal parvoviruses (for example, canine parvovirus and feline panleukopenia virus) to prevent disease in pets. Prevention emphasizes hygiene and avoiding exposure, particularly for pregnant women. Parvovirus B19 is widely distributed with outbreaks in settings involving close contact.