Family: Papillomaviridae Flashcards
Properties of Family Papillomaviridae
Non-enveloped, spherical, icosahedral symmetry
Genome consists of a single molecule of circular double-stranded DNA
Replication of Family Papillomaviridae
Linked to the growth and differentiation of cells in stratified squamous epithelium of skin and mucous membranes
Infect keratinocytes in basal layer of epithelium that becomes exposed through micro-wounds
Viral genomes are established as low copy episomes
Virus accumulation and associated cytopathology are most noticeable in stratum granulosum
Virions are shed from the uppermost layers of epithelium
DNA of benign warts
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
Oncogenic Papillomaviruses
In papillomavirus induced malignant cancers, the viral DNA is integrated into that of the host
Integration disrupts one of the early genes, E2, which is a viral repressor
However, viral oncogenes (E6 and E7) remain intact and cause malignant transformation
Transmission of Bovine Papillomatosis
Contaminated fomites (milking equipment, halters) Sexual transmission of veneral warts in cattle
Fibropapilloma
- causes
- locations in females
Caused by Bovine Papillomavirus types 1, 2, and 5
Lesions vary from small firm nodules to cauliflower-like growths
Common on the udder, teats, head, neck, and shoulders
May also occur in the omasum, vagina, vulva, penis, anis
Fibropapilloma in bulls
In young bulls, fibropapillomas are found on the penis but not on the prepuce
Warts grow rapidly and surround tip of the penis
May render them of no value as bull studs
Cutaneous Papillomas
Bovine Papillomavirus type 3
Lesions lack a fibrous core, flat with a broad base
Lesions tend to persist
Bovine Papillomavirus 4
Can cause transient papillomas in the alimentary tract
Braken Fern
Ingestion of braken fern can result in transition to invasive carcinoma of the alimentary tract from BPV 4
In cattle that eat braken fern, papillomavirus types 1 and 2 may contribute to the syndrome of enzooti hematuria that is characterized by hematuria and/or urinary bladder
Treatment of Bovine Papillomatosis
Surgical excision, or cryosurgery with liquid nitrogen
Topical agents, Podophyllin and DMSO
Bovine IFN-alpha
Papilloma virus that infects dogs
Canine Oral Papillomatosis
Type of infection and lesions found with Canine Oral Papillomatosis
Contagious, self-limiting disease affecting oral cavity
Warts begin on the lips, can spread to the buccal mucosa, tongue, palate, and pharynx, do not extend below epiglottis or into esophagus
Characterized histologically by epithelial hyperplasia and cytoplasmic vacuolization (koliocytosis)
Clinical signs of Canine Oral Papillomatosis
Halitosis (bad breath), hemorrhage, ptyalism (hypersalivation)
Numerous warts may interfere with mastication and deglutition
Ocular warts in the conjunctiva, cornea, and eyelid margins
Recovered dogs are refractory to reinfection
Treatment of Canine Oral Papillomatosis
Surgival excision, cryosurgery
Autogenous vaccines - a wart is removed, made into a crude vaccine, and injected into the same animal
