Papova Viruses

fackrel@Uwindsor.ca

Papova Viruses

• Structure

• Classification

• Multiplication

• Clinical manifestations

• Epidemiology

• Diagnosis

• Control

Baron’s Web site

Genome

Genome Function

Papova virus Replication

PPT Slide

PPT Slide

Classification

Pathogenesis

• Mechanisms not well understood.

• Human papillomavirus are associated with the development of malignant genital lesions
  • types 16 and 18,.

• Cofactors are required for cancer development.

Multiplication

• Viral DNA latent in basal cells of benign lesions.

• Replication occurs in differentiating cells.

• Capsid proteins and viral particles are found only in terminally differentiated epidermal cells.

• Viral DNA is integrated in cancer cells, which contain no replicating virus.

They induce tumors in laboratory rodents.

• They induce tumors in laboratory rodents.

Clinical manifestations

• Polyomaviruses exhibit asymptomatic persistent infections in humans.

• The JC type of polyomavirus causes progressive multifocal leukoencephalopathy in humans.

Clinical manifestations

• Benign papillomatous lesions of skin and mucous membranes
  • (common warts, plantar warts, flat warts, anogenital warts, epidermodysplasia verruciformis, and laryngeal papillomas).

• Cervical intraepithelial neoplasia and cervical cancer are associated with human papillomavirus infection.

Epidemiology

• Infections occur during childhood,
  • 70 to 80 % of adults have antibodies.

• Route of transmission is unknown
  • may be respiratory.

• No animal reservoirs.

• Some humans also possess antibodies to SV40, a simian virus.

Transmission

• Papillomaviruses widely distributed

• Transmission by contact.

• Genital warts sexually transmitted.

• Laryngeal papillomas may acquired during birth from a mother with genital warts.

Control

• Localized destructive methods
  • application of caustic agents
  • Most warts regress spontaneously

• Sterilize instruments
  • after examination of patients

• Educate Public
  • prevent sexual transmission..

• Interferon
  • effective vs laryngeal papillomas, common warts, and anogenital warts.

Diagnosis

Host Defenses

• Infections are persistent
  • induce humoral antibodies and cytotoxic T cells.

• Immunosuppressed
  • Impaired cell-mediated immunity
  • progressive multifocal leukoencephalopathy.

• Interferon
  • weakly induced
  • variable sensitivity
  • transformation by polyomaviruses inhibited

DONE!!!