Parvovirus B19

Question 0

Tropism?

Answer 0

Exclusively erythroid progenitor cells

Question 1

Genetic organization?
Envelope?
Capsid symmetry?

Answer 1

ssDNA
Envelope? Nope
Capsid symmetry? Icosahedral

Question 2

Parvovirus gains entry to its host cell and establishes infection by . . .

Answer 2

Clathrin-mediated endocytosis of the virion into the host cell. Once within the host cell, Parvovirus enters the host cell cytoplasm via permeabilization of the host endosomal membrane.

Question 3

Parvovirus replicates by . . .

Answer 3

Rolling-hairpin replication.

Question 4

The relationship between the viral protein NS1 and pathogenesis is . . .

Answer 4

NS1 “nicks” between coding sequences and hairpins, creating a 3’ end that initiates rolling-hairpin replication
NS1 is a viral protein that creates “nicks” between hairpin and coding sequences on the virus DNA, creating a 3’ end that allows for the initiation of rolling-hairpin replication.

Question 5

Presentation of erythema infectiosum is…

Answer 5

Febrile symptoms 7-10 days after exposure, then “slapped cheek” rash several days later. 2-3 days later, macular rash may appear on extremities in lacy reticular pattern. Adults can have athralgia instead of macular rash.

Question 6

Erythema infectiosum is treated with…

Answer 6

Symptom management. It will stop after a while.

Question 7

Transient aplastic crisis occurs when…

Answer 7

You have a low reticulocyte count and absence of erythroid progenitor cells.

Question 8

Other parvovirus diseases include….

Answer 8

Polyarthropathy Syndrome (symmetrical arthralgia; most prevalent in adult women) 
Pure Red-Cell Aplasia (seen in cases of chronic B19 infection) 
Hydrops Fetalis (fetal edema)

Question 9

In addition to clinical signs, parvovirus infection is diagnosed by. . .

Answer 9

detection of B19V IgM antibodies.

B19V IgG is detectable by the seventh day of illness and persists throughout life.