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Flashcards in Major DNA viruses Deck (103)
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1

Molluscum Contagiosum

Poxviridae

2

B19

only human parvovirus
ss, linear DNA, naked icosahedral
causes Fifth's disease - slapped cheek rash
Trans: respiratory and oral secretion

3

What sort of cells does B19 preferentially infect?

mitotically active erythroid precursor cells in the bone marrow
infects proerthyroblast

4

Describe the lytic phase of B19

viremia is established
viral shedding, moves out of bone marrow
flu like symptoms

5

Describe the non infections immune response of B19

circulating immune complexes that cannot fix complement results in erythematous, maculopapular rash, arthralgia, arthritis (last two rare)

6

What is important for clearing B19?

IgG

7

what causes common rash illness in school aged children?

B19

8

lacy reticular maculopapular rash on trunk and extremities

B19

9

Rash appears with IgM

B19

10

what is the concern with a B19 infection in a sickle cell patient?

Aplastic crisis - drop in RBCs

11

concerns with Intrauterine infection of B19

hydrops fetalis or fetal death

12

Rash appears with IgM

B19

13

How would you treat acute vs. chronic B19?

since mild - acute treat with supportive care, ibuprofen for fever and topical anesthetic or antihistamine
For chronic which can be seen in IC pts - IV immunoglobins

14

Adenovirus

DsDNA - linear
non enveloped
respiratory trans. via inhalation of droplets or eye contact
GI trans. - fecal-oral route

15

Pathogenesis of Adenovirus

typically infects where comes in contact with mucoepithelium
commonly infects local lymphoid tissue - conjunctiva, adenoids, tonsils, respiratory, peyer's patches
*typically not pathogenic

16

Where can Adenovirus persist?

in tonsils and adenoids in childern
in intestines in adults

17

How does Adenovirus interfere with host defenses?

interferes by blocking IFN and T cells

18

Viral oncogenes of Adenovirus

lytic in nature so tumorgenesis is not concern
late proteins E1A and E1B leads to cell growth
E1A inactivates pRB (retinoblasts)
E1B inactivates p53 (mediates cell apoptosis)

19

What are some clinical manifestations of Adenovirus

Acute febrile pharyngitis
Pharyngoconjunctival fever
Acute respiratory disease
cold, laryngitis, croup, bronchiolitis, viral pneumonia
"shipyard eye" -epidemic keratoconjunctivitis
cervicitis and urethritis - rare in women
acute gastroenteritis in infants

20

With Adenovirus infections in childern, what symptoms would you see in infants and young children versus older children?

infants and young - acute febrile - stuffy nose, fever, sore throat
Older children - Pharyngoconjunctival fever - tends to occur in outbreaks. associated with underchlorinated pools

21

Notice lots of military recruits have Acute respiratory disease. Symptoms include fever, runny nose, cough and pharyngitis. A couple of infected recruits also present with conjunctivitis. What could it be?

Adenovirus

22

papillomaviridae

HPV
small, circular (so has own polymerase to make DNA but use host polymerase for RNA), in nucleus, ds, non enveloped

23

Papilloma

benign
squamous epithelial growth
wart
verruca

24

HPV encodes proteins that promote

cell growth
lytic infections in permissive cells
transforming, oncogenic infection in non permissive cells

25

What does HPV cause?

warts, condylomas, papillomas and cervical carcinomas

26

How long could HPV incubate?

2 weeks to 1 year

27

what strains of HPV could cause Anogenital warts?

6 and 11

28

what strains of HPV could cause Cervical carcinomaL?

16 and 18

29

HPV protein E1

binds DNA at ori and promotes viral DNA replication and has helicase activity

30

HPV protein E2

binds DNA
helps E1
and activates viral mRNA synthesis