Parvovirus B19


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Parvovirus B19


Pigmented skin disorders



Acneiform skin disorders

Acne vulgaris



Hidradenitis suppurativa

Papulosquamous and inflammatory skin disorders

Contact dermatitis

Atopic dermatitis

Lichen planus

Pityriasis rosea


Seborrhoeic dermatitis


Keratotic skin disorders

Actinic keratosis

Vesiculobullous skin disorders

Epidermolysis bullosa

Bullous pemphigoid

Pemphigus vulgaris

Desquamating skin disorders

Erythema multiforme

Stevens-Johnson syndrome

Skin integrity disorders

Pressure ulcer




Skin infections




Necrotizing fasciitis

Human papillomavirus

Varicella zoster virus

Poxvirus (Smallpox and Molluscum contagiosum)


Herpes simplex virus


Malassezia (Tinea versicolor and Seborrhoeic dermatitis)

Pediculus humanus and Phthirus pubis (Lice)

Sarcoptes scabiei (Scabies)

Human herpesvirus 6 (Roseola)

Parvovirus B19

Varicella zoster virus

Measles virus

Rubella virus

Skin neoplasms

Vascular tumors

Human herpesvirus 8 (Kaposi sarcoma)


Skin cancer

Hair and nail disorders

Alopecia areata

Telogen effluvium


Integumentary system pathology review

Pigmentation skin disorders: Pathology review

Acneiform skin disorders: Pathology review

Papulosquamous and inflammatory skin disorders: Pathology review

Vesiculobullous and desquamating skin disorders: Pathology review

Bacterial and viral skin infections: Pathology review

Skin cancer: Pathology review

Viral exanthems of childhood: Pathology review


Parvovirus B19


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USMLE® Step 1 questions

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Parvovirus B19

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USMLE® Step 1 style questions USMLE

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A 3-year-old boy is brought to the office by his parents due to a facial rash. The parents report the patient has been having a runny nose, diarrhea, and a fever of up to 38.3 ºC (100.9 ºF), for the past three days. Today, the patient developed a rash on his face, shown below. Laboratory evaluation is significant for a hemoglobin of 9 g/dL and a leukocyte count of 3000 cells/mm3. Which of the following best describes this patient's characteristics of the causative organism?
 Reproduced from ">Wikimedia Commons  

Memory Anchors and Partner Content

External References

First Aid








Hydrops fetalis

parvovirus B16 p. 181, 178

Parvovirus B16

aplastic anemia p. 417

hereditary spherocytosis p. 417

hydrops fetalis p. 181

rash p. 178


Content Reviewers

Rishi Desai, MD, MPH


Kaylee Neff

Tanner Marshall, MS

Parvovirus B19 is the smallest known DNA animal virus, coming in at an itty bitty 18 to 28 nanometers in diameter.

In comparison, the average size of a single human red blood cell is a whopping 7200 nanometers!

While it’s mostly known for causing fifth disease, or “slapped cheek syndrome,” in children, parvovirus B19 can also affect adults and it can cause serious illness in individuals with pre-existing conditions like sickle-cell anemia and HIV.

Parvovirus B19 is part of the parvoviridae family.

It’s a single-stranded DNA virus surrounded by an icosahedral capsid, which is a spherical protein shell made up of 20 equilateral triangular faces.

And it’s “naked” because the capsid isn’t covered by a lipid membrane.

Parvovirus B19 is primarily transmitted by respiratory droplets when someone coughs or sneezes.

You can also catch it via an infected blood transfusion and a pregnant female can also transmit it through the placenta to her unborn child.

Now, although the virus first enters cells of the respiratory tract by binding to receptors on host cells, it doesn’t replicate in them.

Instead it keeps travelling through cells and into the circulatory system until it reaches bone marrow, where red blood cells are made, a process called erythropoiesis.

Once there, parvovirus B19 uses receptor-mediated endocytosis to enter erythroid progenitor cells, also called proerythroblasts, the early cells that eventually become red blood cells.

It then uses these cells’ DNA replication machinery in the nucleus to replicate its DNA and assemble new copies of the virus.

Why not simply replicate in cells of the respiratory system?

Well it turns out that Parvovirus B19 needs two things: it prefers to bind to a specific receptor, the P antigen, which is found in large numbers on proerythroblasts’ cell membrane and it needs cells that pass through the S phase of the cell cycle, which is the phase where cell DNA is replicated.

Since the body is constantly producing new red blood cells, there are always proerythroblasts going through the S phase at any given time.


Parvovirus B19 is a single-strand DNA virus of the parvoviridae family, which is commonly known for causing diseases in the pediatric population, though it can also affect adults.

Parvovirus B19 is primarily spread by infected respiratory droplets and causes the Fifth disease or "slapped cheek syndrome" in children, characterized by a distinctive red rash on the cheeks. It can also cause redness and joint pain (arthritis) in adults. Parvovirus B19 can also affect the bone marrow, resulting in anemia secondary to decreased erythropoiesis. Anemia can even be worse in patients with pre-existing bone marrow stress, for example, sickle cell anemia or hereditary spherocytosis which can lead to an aplastic crisis.

Treatment for parvovirus B19 varies according to the symptoms, and can involve blood transfusion for transient aplastic crisis and hydrops fetalis and immune globulin intravenous therapy for chronic infections.


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