Parvovirus Flashcards
What 2 genuses are part of the family parvoviridae?
Parvovirus and Dependovirus
<p>
| The genus dependovirus requires what for replication?</p>
<p>
| A helper virus. Everyone should love Mare.</p>
Parvoviridae viruses are what kind of viruses?
Linear, single-stranded DNA viruses
What kind of capsid do parvoviridae viruses have? Enveloped or not?
Icosahedral capsid. No envelope.
T or F. In the family parvoviridae, an equal number of progeny contain either positive or negative strands.
T
Where does replication and assembly occur for parvoviridae viruses? What kind of cells do they replicate in?
In the nucleus. Rapidly dividing cells (thus providing replication function).
What dz does parvo B19 cause?
Erythema infectiosum: a mild, common childhood rash.
What percentage of the adult population is seropositive for parvo B19?
50%. Conversion usually occurs after school age is attained. Ab’s provide protective immunity.
How is parvo B19 spread?
Direct contact with respiratory secretions that occurs prior to the rash.
What are the 2 phases of parvo B19 infection?
- Initial viremia presents with FLS
- Second phase is when rash may occur
Notes: symptoms are immune-mediated and 4/5 will show symptoms.
What is the other name for erythema infectiosum?
Fifths dz.
What is the characteristic rash of Fifths Dz?
“slapped cheek” rash. Also lacy red rash on trunk and limbs.
What is the usual course of fifths dz?
Resolves in 7-10 days.
What is the adult presentation of fifths dz?
Joint pain or swelling (polyarthritis) along with FLS. Adults tend to have less rash.
What can parvo B19 cause in sickle cell pts?
Transient aplastic crisis.
How does parvo B19 cause a transient aplastic crisis in sickle cell pts?
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.
ICP pts develop what with parvo B19 infection?
Chronic anemia
Parvo B19 can be transmitted placentally. What is the consequence of this?
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.
How is dx of parvo B19 made?
Most often made by appearance of rash. Serologic and viral DNA testing of blood sample if necessary.
What dz is fifths dz sometimes confused with?
Rubella
What is the tx for fifths dz?
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.
