poxiviridae

• What is the shape of the Poxviridae virus?

  Parallelepiped
• What is the general size of the Poxviridae virus?

  300 - 450 nm X 170 - 260 nm
• What type of genome does the Poxviridae virus have?

  DNA genome in a dumb-bell core
• What are the two types of soluble antigens in Poxviridae?

  L and S antigens
• What are the stages of Poxviridae propagation?

  1. Adsorption on specific cellular receptors
  2. Penetration into the infected cell
  3. Viral genome release and early mRNA synthesis
  4. DNA replication
  5. Transcription of early and intermediate proteins
  6. Synthesis of intermediate and late mRNAs
  7. Synthesis of other components
  8. Assembly of new viral particles
• Where does Poxviridae propagate in the infected cell?

  Only in the cytoplasm
• How does Poxviridae leave the infected cell?

  By lysis and/or exocytosis
• What is the resistance of Poxviridae to physical and chemical factors?

  Relatively resistant, heat labile
• What are the specific infections caused by Poxviridae in humans?

  Smallpox and moluscum contagiosum
• How is smallpox spread?

  By air-droplet, contact, and placenta
• What is the incubation period for Variola major?

  12 - 14 days
• What are the two clinical forms of smallpox?

  Variola major and Variola minor
• What is the mortality rate of Variola major?

  Up to 90%
• What is the incubation period for moluscum contagiosum?

  14 - 50 days
• What are the laboratory diagnosis methods for Poxviridae?

  1. Electronic microscopy
  2. Direct light-optical microscopy
  3. Immunofluorescence microscopy
  4. PCR for subtype identification
  5. Virus isolation methods
  6. Serological methods
• Who administered the first smallpox inoculation?

  Edward Jenner
• What did Edward Jenner observe about milkmaids?

  They seemed immune to smallpox
• What was the purpose of variolation?

  To create immunity against smallpox
• What is the incubation period for cowpox?

  10 days
• What is the lethality rate of monkeypox?

  1% - 11%
• What are the characteristics of molluscum contagiosum?

  • Widespread disease
  • Pearly-shaped nodules on skin
  • Incubation period: 14 - 50 days
  • Chronic for months/years
  • Can be complicated by bacterial infection
• What are the characteristics of cowpox?

  • Zoonosis in Europe and Russia
  • Reservoir: rodents
  • Infection from sick cows
  • Incubation period: 10 days
  • Skin changes similar to smallpox
• What are the characteristics of ORF disease?

  • Disease in goats and sheep
  • Infection through intimate contact
  • Non-painful papulovasicular lesions
  • Does not transmit infection
• What is the replication process of Parvoviridae?

  • Adsorption on P-antigen receptor
  • Propagates in primary erythroid cells
  • CPE: giant early erythroid cells
  • Resistant to chemical and physical agents
• What is the incubation period for Tanapox?

  4 days
• What is the effect of Poxviridae on cellular synthesis?

  Almost complete blockade of synthesis
• What is the role of the nucleoprotein in Poxviridae?

  Part of the viral structure
• What is the significance of the haemagglutinin in Poxviridae?

  It is an antigen in the virus
• What is the role of the outer sheath in Poxviridae?

  Modified cell membrane of the virus
• What is the incubation period for smallpox?

  12 - 14 days
• What is the primary mode of transmission for monkeypox?

  Contact with infected animals
• What is the incubation period for molluscum contagiosum?

  14 - 50 days
• What is the primary characteristic of the rash in smallpox?

  Develops in stages: papules to crusts
• What is the significance of the two-wave temperature curve in smallpox?

  Indicates primary and secondary viremia
• What is the role of the lymph nodes in smallpox infection?

  Facilitate virus spread to the blood
• What is the role of the spleen in smallpox pathogenesis?

  Site of viral proliferation
• What is the significance of the cowpox virus in immunology?

  Led to the development of smallpox vaccine
• What is the role of the immune sera in laboratory diagnosis?

  Used to prove the presence of antigens
• What is the incubation period for ORF disease?

  Varies with contact duration
• What is the significance of the Guarneri inclusions?

  Indicate viral infection in cells