(DNA VIRUSES) Lesson 8: Papovaviridae

Question 1

General description of Papovaviridae

Answer 1

 Non-enveloped, double-stranded DNA
viruses
 Icosahedral symmetry
 Contains sixteen genera

Question 2

In the Family Papovaviridae, this process is highly specialized
requiring organotypic raft cultures of
keratinocytes or epithelial xenografts
in immunocompromised rodents

Answer 2

cultivation

Question 3

Papovaviridae causes what?

Answer 3

papillomas and
fibropapillomas

Question 4

malignant transformation of alimentary and urinary tract papillomas may occur
in cattle ingesting this plant called

Answer 4

bracken

Question 5

This may occur in cattle ingesting bracken

Answer 5

malignant transformation of Alimentary and Urinary Tract Papillomas

Question 6

It is aetiologically implicated in equine sarcoids

Answer 6

bovine papillomavirus 1

Question 7

It is aetiologically implicated in equine sarcoids

Answer 7

Bovine papillomavirus 1

Question 8

Bovine papillomavirus 1 causes what?

Answer 8

Equine sarcoids

Question 9

host-specific, presents proliferative lesions in specific-anatomical
sites

Answer 9

Papovaviridae

Question 10

They are composed of finger-like projections of
proliferating epithelium supported by a thin core of mature fibrous
tissue

Answer 10

typical papillomas

Question 11

It causes papillomas (warts) by infecting and causing hyperplasia of squamous epithelial cells.

Answer 11

Papilloma virus

Question 12

It causes a nephritis and/or urethritis

Answer 12

BK virus (Polyomavirus)

Question 13

Pathogenesis of Papovaviridae

Answer 13

 Papillomaviruses infect the basal cells of squamous epithelium.
 Infected cells proliferate but differentiation is delayed. Viral gene
expression is restricted during this stage
 After proliferative phase, cellular differentiation begins in the more
superficial epithelial layers followed by full gene expression resulting
to the production of viral capsids.
 New virions can be visualized by electron microscopy in the nuclei of
differentiated keratinized cells.
 Release of virus occurs during desquamation of infected cells from
the surface of lesions.

Question 14

It infect the basal cells of squamous epithelium

Answer 14

Papillomaviruses

Question 15

Viral gene
expression of the papillomavirus is restricted during this stage

Answer 15

proliferative phase

Question 16

Release of Papillomaviruses occurs during ___________ from
the surface of lesions.

Answer 16

desquamation of infected cells

Question 17

Papovaviridae is diagnosed through?

Answer 17

 Clinical appearance of warts

Histopathology on a biopsy
 Electron microscopic examination of specimens from the epidermis

Question 18

Electron microscopic examination of papillomaviruses specimens from this organ
may reveal characteristic virus particles.

Answer 18

epidermis

Question 19

It is a flat, distinct, discolored area of skin. It usually does not include a change in skin texture or thickness.

Answer 19

macule

Question 20

a small, raised, solid pimple or swelling, often forming part of a rash on the skin and typically inflamed but not producing pus

Answer 20

Papule

Question 21

DNA strand of Papovaviridae

Answer 21

double-stranded DNA