Test 2- Papillomaviridae

Question 1

Family: Papillomaviridae

 General Properties:

Answer 1

 Non-enveloped, spherical, 55 nm in diameter, with icosahedral symmetry.
 Genome consists of a single molecule of circular double-stranded DNA.
 Resistant viruses, survives lipid solvents and detergents, low pH, and high temperatures.

 Can transform cultured cells.

• ONCOGENTIC

Question 2

Papillomaviruses produce

Answer 2

Papillomaviruses produce papillomas (warts) on the skin and mucous membranes of most animal species.

 These Warts are benign neoplasms are hyperplastic epithelial outgrowths that generally regress spontaneously.

 Are usually species and site specific.

 Serologic cross-reactivity has not been detected among papillomaviruses of different species.

 Occasionally, however, they may progress to malignancy, which in part is a property of specific virus strains. Example, HPV causing cervical carcinoma in women.

Question 3

Answer 3

Warts (Benign form)

Question 4

Answer 4

Malignant

Question 5

 Replication:

Answer 5

Replication of papillomaviruses is linked intimately to the growth and differentiation of cells in stratified squamous epithelium of the skin and some mucous membranes.

 Papillomaviruses infect keratinocytes in the basal layer of the epithelium that becomes exposed through micro-wounds.

 On infection, the viral genomes are established as low-copy episomes.

 The viral genomes are replicated in synchrony with cellular DNA replication.

 After cell division, one daughter cell migrates away from the basal layer to outer layers of epidermis and undergoes differentiation.

 Differentiation of HPV-positive cells induces the productive phase of the viral life cycle (large number of genome copies), which requires cellular DNA synthesis machinery.

 Virus accumulation and associated cytopathology are most noticeable in stratum granulosum.

 Virions are shed from the uppermost layers of the epithelium.

Question 6

The story of Oncogenic Papillomaviruse

Answer 6

 In benign warts, the papillomavirus DNA is episomal, meaning it is not integrated into the host-cell DNA and persists as an autonomously replicating episome.

 In papillomavirus-induced malignant cancers the viral DNA is integrated into that of the host. Thus, integration probably is necessary for malignant transformation.- VIRUS PRODUCTION STOPS, and VIRUS BECOMES ONCOGENTIC

 Integration disrupts one of the early genes, E2, which is a viral repressor.

 However, the viral oncogenes (e.g., E6 and E7) remain intact and cause the malignant transformation.

Question 7

Oncoproteins of Papillomaviruses Papillomavirus (HPV) E6 & E7 proteins

Answer 7

E6 blocks p53(repairs DNA damage)- thus DNA damage can not be repaired or destroyed, so you get get abnormal growth

Question 8

Bovine Papillomatosis

Host and Transmission

Answer 8

 Host: Cattle.
 Warts are more commonly seen in cattle than in any other domestic animal.

 All ages are susceptible, incidence is highest in calves and yearlings.

Natural bovine papillomavirus infection of horses may occur after exposure of the horses to cattle.

 Transmission:

 Virus is transmitted between animals by contaminated fomites, such as contaminated milking equipment, halters, nose leads, grooming and earmarking equipment, etc.

 Sexual transmission of venereal warts in cattle.

Question 9

Bovine Papillomatosis

Fibropapilloma

Answer 9

Mostly caused by Bovine papillomavirus types 1, 2, and 5

 Papillomas have a fibrous core covered to a variable depth with stratified squamous epithelium, the outer layers of which are hyperkeratinized.

 Lesions vary from small firm nodules to large cauliflower-like growths.

 Grayish to black in color and rough and spiny to the touch.

Question 10

Answer 10

Multiple Fibropapillomas

Question 11

Answer 11

Fibropapilloma

Question 12

Bovine Papillomatosis

 Fibropapilloma:

Answer 12

 Fibropapillomas are common on the udder and teats and on the head, neck, and shoulders.
 They may also occur in the omasum, vagina, vulva, penis, and anus.
 Young bulls: Fibropapillomas are found frequently on the penis, but not on prepuce.

Wart grows rapidly and may surround tip of penis. This may render them of no value as bull studs.

Question 13

Answer 13

Teat Papillomas

Question 14

Answer 14

Fibropapilloma of the Glans Penis

Question 15

Answer 15

Bovine Papillomatosis

Fibropapilloma of the Glans Penis

Question 16

Cutaneous papilloma

Answer 16

Bovine Papillomatosis Bovine papillomaviruses type 3.

 Lesions lack a fibrous core.
 Are usually flat (unlike papillomatosis) with a broad base, unlike the more usual fibropapillomas that protrude and are often pedunculated.  Lesions tend to persist.

Question 17

Bovine Papillomatosis

 Bracken Fern and Bovine Papillomaviruses:

Answer 17

 Bovine papillomavirus 4 can cause transient papillomas in the alimentary tract.

I_ngestion of the bracken fern_ can result in transition to invasive carcinoma of the alimentary tract.

 This is because bracken fern contains carcinogens, mutagens, and immunosuppressive chemicals.

_ In cattle that eat bracken fern, papillomavirus typ_es 1 and 2 may also contribute to the syndrome of “enzootic hematuria” that is characterized by hematuria and/or urinary bladder cancer.

Question 18

Answer 18

Acute Bracken Fern Poisoning Thrombocytopenia with suffuse hemorrhage

Bracken fern

Question 19

Bovine Papillomatosis

 Diagnosis:

Answer 19

 Viruses visible in lesion biopsies by TEM.

 PCR, DNA hybridization assays.

Question 20

Bovine Papillomatosis

 Treatment:

Answer 20

 Treatment:
 Surgical excision, or cryosurgery with liquid nitrogen.
 Topical agents, Podophyllin and undiluted medical grade DMSO (DiMethylSulfOxide)

 Bovine interferon-alpha

VACCINE- WART VACCINE

Question 21

Canine Oral Papillomatosis

Answer 21

 Contagious, self-limiting disease affecting oral cavity of dogs

 The warts usually begin on the lips, and can spread to the buccal mucosa, tongue, palate, and pharynx. Later may become roughened and cauliflower-like. Do not extend below epiglottis or into esophagus.

 Characterized histologically by epithelial hyperplasia and cytoplasmic vacuolization (koilocytosis)

 Lesions typically regress spontaneously

 Progression to squamous cell carcinoma occurs very rarely.

Question 22

Answer 22

Multiple Papillomas on the Lips of a Young Dog

Question 23

Answer 23

Extensive Oral Papillomatosis

Question 24

Canine Oral Papillomatosis

 Clinical signs:

Answer 24

 Halitosis (bad breath), hemorrhage, ptyalism (Hypersalivation), discomfort.
 Numerous warts may interfere with mastication and deglutition.
 Warts may regress, or secondary bacterial infection and ulceration may occur.

 Ocular warts: Conjunctiva, cornea, eyelid margins.

 Recovered dogs are refractory to reinfection.

Question 25

Canine Oral Papillomatosis

 Treatment:

Answer 25

 Treatment:
 Surgical excision, cryosurgery, electrosurgery.
 Autogenous Vaccines (a wart is removed, made into a crude vaccine, and injected into the same animal) may be tried. Efficacy doubtful.

Question 26

Equine Sarcoids

Answer 26

 Sarcoids commonly occur in horses, donkeys and mules between 1 to 6 years of age. Most common neoplasm in Horses.

 They are locally invasive benign fibroblastic skin tumors.

 Associated with bovine papillomaviruses 1 or 2.

 Sarcoids do not metastasize. They may persist for life. Are locally invasive. Recur after surgical removal.

Question 27

Answer 27

Proliferation of dermal fibroblasts and the overlying epidermis

Question 28

Equine Sarcoids

 Transmission:

Answer 28

 The mode of transmission has not been confirmed.
 Flies act as vectors?
 Fomites, transmitted via stable management practices.

Breed susceptibility with major histocompatibility complex has been defined.

Question 29

Equine Sarcoids

Susceptible Breeds

Answer 29

Arabian Horse

Appaloosa Horse

American Quarter Horse

Question 30

Equine Sarcoids

Less Susceptible Breeds

Answer 30

Standardbred Horse

Thoroughbred Horse

Question 31

Equine Sarcoids

Lesions

Answer 31

 Lesions commonly occur in traumatized areas.
 Single or multiple.
 Growths may reach size of man’s feast, bulge under skin.

 May become ulcerated.

Question 32

Answer 32

Palpebral sarcoid—multilobed SC lesion; small nodular lesion in lower lid

Question 33

Answer 33

Leg Sarcoid

Question 34

Answer 34

Muzzle Sarcoid

Question 35

Equine Sarcoids

The clinical appearance of a sarcoid affected wound is often very similar

Answer 35

Equine Sarcoids

The clinical appearance of a sarcoid affected wound is often very similar to “proud flesh” or exuberant granulation tissue.
However, sarcoids are frequently are seen at sites of previous injury and scarring.

Question 36

Equine Sarcoids

Dx and treatment

Answer 36

 Diagnosis:
 Clinical features.
 Histological examination of biopsy material  Virus detection

 Treatment:
Cryotherapy, Surgical or Laser excision, and Local immune modulation, Local radiotherapy,

Question 37

Can also have papillomatosis in

Answer 37

CATS