Other DNA viruses Flashcards

1
Q

HPV infections are often ______ and do cause latent infection

A

asymptomatic

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2
Q

List two low risk and two high risk HPV strains

A

high risk: 16, 18

low risk: 6, 11

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3
Q

How does HPV transmission occur?

A

contact with fomites- shower floors, etc

requires a break in the epithelial barrier

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4
Q

Immunodeficient patients infected with HPV can develop ______________- warts appear as flat macular erythemetous spots. this can convert to sqamous cell carcinoma in UV light

A

epidermodysplasia veruciformis

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5
Q

In recent years, there as been an increase in ______ cancers caused by the genital HPV serotypes

A

head and neck

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6
Q

Infection with HPV is initiated when the virus infects ______ cells in the skin or mucous membranes

A

basal epithelial

IN the basal cells, replication is not triggered- these cells serve as the latent site

as basal cells divide, the daughter cells move away from the basement membrane and trigger differentiation which activates virus to express early proteins

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7
Q

How does HPV infection cause a wart to form?

A

Expression of the early proteins can be detected in these cells and this includes the Large T antigen protein. Large T causes the cells to proliferate (see below) and as the cells divide, they push up the cells above them ultimately causing the wart to form.

–> virus triggers benign proliferation of epithelial cells at the site of infection. The infections remain above the basement membrane and so are somewhat invisible to the immune system

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8
Q

List some co-factors associated with a wart becoming cancerous

A

cigarettes, sunlight, X rays

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9
Q

Virtually all cervical cancers contain integrated viral DNA and express two proteins ___ and __

A

E6 and E7

integration disrupts E2, which is a negative regulator of E6 and E7

E7 interferes with retinobalstoma (regulates cell cycle)
E6 binds p53 (halts cell division)

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10
Q

Why do warts stain with acetowhite?

A

Because HPV infection alters keratin expression, the wart turns white and can be easily differentiated from the pink color of the normal mucosal surface.

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11
Q

What HPV strains are covered by Guardasil?

A

6, 11, 16, 18

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12
Q

How is molluscum contagiousum transmitted?

A

close contact, sexual activity

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13
Q

_______ is the only pox virus circulating in humans

A

molluscum contagiosum virus

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14
Q

What are common manifestations of molluscum contagiousum virus?

A

cluster of firm umbilicated papules on the skin and genitals

immunocompromised: can persist, become larger

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15
Q

______ is a parvovirus that is non pathogenic and has no associated diseases. It establishes latent infection by integrating into a specific site on chromosome 19. It cannot replicate without a co-infection with adenovirus

A

adeno-associated virus

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16
Q

_____ is the only pathogenic parvovirus in humans

A

parvovirus B19

17
Q

How is parvovirus B19 spread

A

respiratory secretions, higher rates in winter, spring, early summer

18
Q

What diseases are caused by parvovirus B19?

A

erythema infectiosum/ fifth disease/ slapped cheek disease

adults: polyarthropathy

immunocompromised/ hemolsys: aplastic crisis

19
Q

Describe human polyoma viruses

A

BK: kidney infection in transplant patients
JC: progressive multifocal leukoencephalopathy in immunosuppressed