Parvovirus B19 infection
Parvovirus B19 is a single-stranded DNA virus that infects erythrocyte precursors in the bone marrow, producing transient reticulocytopenia that is usually silent but becomes clinically important in three settings: symmetric small-joint arthropathy in adults, aplastic crisis in patients with a hemolytic anemia, and chronic pure red cell aplasia or fetal hydrops when the host cannot clear the virus. Serology confirms infection in the immunocompetent host, while bone marrow pronormoblasts or PCR are needed in the immunosuppressed.
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What this article covers
- Overview
Parvovirus B19 is a single-stranded DNA virus that directly infects erythrocyte precursors in the bone marrow, producing transient reticulocytopenia that is the mechanistic thread linking all of its clinical presentations.
- Epidemiology
A common, person-to-person transmitted infection, with the classic childhood exanthem typically affecting school-age children in outbreaks at daycare and school settings.
- Risk factors
Household, classroom, or occupational exposure to an infected individual during the pre-symptomatic viremic phase, since transmission occurs before any rash or joint symptoms are recognized.
- Pathophysiology
Parvovirus B19 directly infects erythrocyte precursors in the bone marrow, producing a transient arrest of red cell production and a measurable reticulocytopenia during the viremic phase of acute infection.
- Clinical features
Symmetric polyarthralgia or polyarthritis involving the small joints is the dominant presentation in adults, and can closely mimic early rheumatoid arthritis; it is typically self-limited.
- Differential diagnosis
Rheumatoid arthritis: symmetric small-joint polyarthritis lasting more than 6 weeks with radiographic erosions and positive rheumatoid factor/anti-CCP antibodies, whereas parvovirus arthropathy is…
- Diagnosis
In an immunocompetent host, infection is confirmed by parvovirus B19 IgM and IgG serology, the preferred diagnostic method; a positive IgM indicates recent infection, and this single test establishes…
- Management
First, for the typical immunocompetent adult with parvovirus-associated arthropathy, treat symptomatically with ibuprofen 600 mg PO every 6 hours as needed, or naproxen 500 mg PO twice daily as…
- Complications
Aplastic crisis in a patient with an underlying hemolytic anemia or another cause of increased red cell turnover is the most acute, potentially life-threatening complication.
- Prognosis
The typical adult arthropathy is self-limited and resolves without the joint destruction seen in rheumatoid arthritis, which is the key distinguishing outcome from that mimic.
- Prevention
No vaccine exists; prevention relies on standard infection-control precautions during the contagious pre-symptomatic phase in a household, classroom, or workplace outbreak.
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