[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Other DNA viruses](https://durgical.com/en/microbiology/groups/other-dna-viruses/) › Parvovirus B19

[Microbiology](https://durgical.com/en/microbiology/) · [Other DNA viruses](https://durgical.com/en/microbiology/groups/other-dna-viruses/)

# Parvovirus B19

- Virus
- Non-enveloped (naked)
- Droplet
- Exam priority: medium

A tiny virus that causes fifth disease (red cheeks) in children and can cause severe anemia and harm a fetus.

Updated 2026-11-01

Also called: erythema infectiosum, fifth disease, slapped cheek syndrome

## Key points

- The main single-stranded DNA virus that causes human disease; its receptor is the P antigen on erythroblasts.
- Slapped cheeks in the child, arthritis in the adult woman, aplastic crisis in sickle cell disease, hydrops in the fetus.
- Once the rash appears the child is hardly contagious.
- Aplastic crisis: droplet precautions.

## At a glance

**Shape**
Icosahedral, non-enveloped

**Genome**
Linear single-stranded DNA

**Envelope**
Non-enveloped (naked)

**Family**
Parvoviridae (genus Erythroparvovirus)

**Size**
About 20 to 25 nm (among the smallest viruses)

## Morphology

- The only major human single-stranded DNA virus
- Naked, very hardy capsid

## Transmission

- Respiratory secretions
- Transfusion of blood and blood products
- Across the placenta, mother to fetus

**Reservoir:** Humans

### Isolation precautions

What the care team adds to standard precautions.

**Droplet**
Surgical mask within about a metre; single room.

## Virulence factors

- Uses the P antigen (globoside) on erythroid precursors as its receptor
- Kills red-cell progenitors in the bone marrow and halts erythropoiesis for some days
- Immune complexes cause the rash and arthritis, when the patient is hardly contagious any more

## Diseases it causes

- Erythema infectiosum (fifth disease) [Erythema infectiosum (fifth disease, parvovirus B19) →](https://durgical.com/en/conditions/erythema-infectiosum/)
- Hydrops fetalis from fetal anemia
- Transient aplastic crisis and arthropathy

## Clinical picture

- Children: red slapped cheeks followed by a lacy rash on the trunk and limbs
- Adults, especially women: symmetric arthritis of hands, wrists and knees
- Aplastic crisis in people with hemolytic anemia (sickle cell disease, spherocytosis, thalassemia)
- Chronic anemia in the immunocompromised; fetal death or hydrops when infection occurs in pregnancy

## Diagnosis

- Specific IgM in immunocompetent people
- Blood PCR in the immunocompromised and in amniotic fluid or fetal blood
- Very low reticulocytes in aplastic crisis; giant pronormoblasts in the marrow

## Treatment

There is no antiviral. Supportive care; transfusion in aplastic crisis, intravenous immunoglobulin for chronic anemia in the immunocompromised, and intrauterine transfusion for hydrops.

Drug class only; doses and regimens are set by the clinician from the current guideline.

## Prevention

- Hand and respiratory hygiene
- Droplet precautions for aplastic crisis or chronic infection in the immunocompromised
- Fetal ultrasound follow-up if a pregnant woman is infected

## Memory aid

Parvo means small: the smallest virus, with a single strand, attacks the smallest marrow cells (red-cell precursors).

## Test yourself

Think of the answer, then tap the question to see it.

## Which receptor does parvovirus B19 use to infect erythroid precursors?

The P antigen (globoside) on the erythroblast membrane.

## Which complication does parvovirus B19 cause in a patient with sickle cell disease?

A transient aplastic crisis, with severe anemia and almost no reticulocytes.

## Why can a child with erythema infectiosum go back to school?

Because by the time the immune-complex rash appears, the contagious period is over.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/microbiology/parvovirus-b19/)

## Related

- [Human herpesviruses 6 and 7](https://durgical.com/en/microbiology/human-herpesviruses-6-and-7/)
- [Cytomegalovirus](https://durgical.com/en/microbiology/cytomegalovirus/)

## Related conditions

- [Erythema infectiosum (fifth disease, parvovirus B19)](https://durgical.com/en/conditions/erythema-infectiosum/)

## What the colours mean

**Gram-positive**
Thick peptidoglycan wall: stains purple.

**Gram-negative**
Thin wall with an outer membrane: stains pink.

**Acid-fast**
Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain.

**Contact**
Gown and gloves; dedicated equipment. For C. difficile, soap-and-water hand washing.

**Droplet**
Surgical mask within about a metre; single room.

**Airborne**
N95 respirator and a negative-pressure room.

[← Back to the group: Other DNA viruses](https://durgical.com/en/microbiology/groups/other-dna-viruses/)

Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [About Parvovirus B19](https://www.cdc.gov/parvovirus-b19/about/index.html) (CDC, 2024); [Appendix A: Type and Duration of Precautions Recommended for Selected Infections and Conditions](https://www.cdc.gov/infection-control/hcp/isolation-precautions/appendix-a-type-duration.html) (CDC, 2024).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/microbiology/parvovirus-b19/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/parvovirus-b19/