Parvovirus

Question 1

What 2 genuses are part of the family parvoviridae?

Answer 1

Parvovirus and Dependovirus

Question 2

<p>

| The genus dependovirus requires what for replication?</p>

Answer 2

<p>

| A helper virus. Everyone should love Mare.</p>

Question 3

Parvoviridae viruses are what kind of viruses?

Answer 3

Linear, single-stranded DNA viruses

Question 4

What kind of capsid do parvoviridae viruses have? Enveloped or not?

Answer 4

Icosahedral capsid. No envelope.

Question 5

T or F. In the family parvoviridae, an equal number of progeny contain either positive or negative strands.

Answer 5

T

Question 6

Where does replication and assembly occur for parvoviridae viruses? What kind of cells do they replicate in?

Answer 6

In the nucleus. Rapidly dividing cells (thus providing replication function).

Question 7

What dz does parvo B19 cause?

Answer 7

Erythema infectiosum: a mild, common childhood rash.

Question 8

What percentage of the adult population is seropositive for parvo B19?

Answer 8

50%. Conversion usually occurs after school age is attained. Ab’s provide protective immunity.

Question 9

How is parvo B19 spread?

Answer 9

Direct contact with respiratory secretions that occurs prior to the rash.

Question 10

What are the 2 phases of parvo B19 infection?

Answer 10

1. Initial viremia presents with FLS
2. Second phase is when rash may occur
   Notes: symptoms are immune-mediated and 4/5 will show symptoms.

Question 11

What is the other name for erythema infectiosum?

Answer 11

Fifths dz.

Question 12

What is the characteristic rash of Fifths Dz?

Answer 12

“slapped cheek” rash. Also lacy red rash on trunk and limbs.

Question 13

What is the usual course of fifths dz?

Answer 13

Resolves in 7-10 days.

Question 14

What is the adult presentation of fifths dz?

Answer 14

Joint pain or swelling (polyarthritis) along with FLS. Adults tend to have less rash.

Question 15

What can parvo B19 cause in sickle cell pts?

Answer 15

Transient aplastic crisis.

Question 16

How does parvo B19 cause a transient aplastic crisis in sickle cell pts?

Answer 16

B19 infects and lyses erythroid precursor cells resulting in loss of RBC production during infxn (7-10 days). Sickle cell pts cannot tolerate abscence of precursor pool resulting in severe anemia.

Question 17

ICP pts develop what with parvo B19 infection?

Answer 17

Chronic anemia

Question 18

Parvo B19 can be transmitted placentally. What is the consequence of this?

Answer 18

Most infxns are of no concern. However, 5% of infxns can result in severe fetal anemia, hydrops fetalis, or miscarriage. These are most common during the first half of pregnancy.

Question 19

How is dx of parvo B19 made?

Answer 19

Most often made by appearance of rash. Serologic and viral DNA testing of blood sample if necessary.

Question 20

What dz is fifths dz sometimes confused with?

Answer 20

Rubella

Question 21

What is the tx for fifths dz?

Answer 21

Treat the FLS and the itchy rash. Anemia pts may require a blood transfusion. Difficult to prevent b/c infectious period occurs prior to rash. There is no vaccine. General hygiene practices may limit spread.