Parvovirus and Pox Flashcards
Parvovirusstructure
Linear, ss DNA with an icosahedral capsid and no envelope
Where do Parvovirus’ replicate
In the nucleus of actively dividing cells because they are so small they can’t make their own DNA polymerase
How is Parvo spread?
respiratory secretions
What does Parvovirus B19 cause
Erythema Infeciosum. Mild childhood rash. 50% of adult population is seropositive for this
What does the erythema infectiosum rash look like>
On the face it is called “slapped cheek” appearance. Appears “lacy” on the trunk and limbs.
Adults tend to have less rash and more arthritis/ flu-like symptoms
Describe the infection
Biphasic. there is a lytic phase followed by a non-infectious phase. During the lytic phase (infectious phase) virus is present in the throat, viremia is occurring, and the pt experiences non-specific flu-like symptoms. Hemoglobin and reticulocyte levels are decreased
In the noninfectious period the rash appears. Reticulocyte and hemoglobin count still low
What kinds of pts are most susceptible to B19
Sickle cell anemia pts may have aplastic crisis.
Chronic anemia may occur in immunocompromised
Transplacental transmission (from mother to child) can cause severe fatal anemis in the child)
Diagnosis of B19
Rash
Treatment of B19
treat the flu-like symptms and itchy rash
Anemia pts may need transfusions
No Vaccine
Why is B19 often called fifth disease
The fifth most common childhood rash
What is the microbiology of the poxviridae family
Large, complex structure
Greater than 200 kbp in diameter (Parvo was like 6)
DS linear DNA genome
The poxviridae is pretty much the only DNA virus that doesnt replicate in the nucleus. WHere does it replicate
Cytoplasm
Just like all RNA viruses (except flu) replicate in the cytoplasm
Variola =
Smallpox
What the hell is molluscum contagiosum
virus that is a member of the poxviridae family
Symptoms of molluscum contagiosum
lesions on face, trunk, limbs in children
In adults, Sexually transmitted. lower abdomen lesions.
Lesions disappear in 2-12 mths
