38 - Retroviridae

Question 1

Retroviridae

Answer 1

• Etymologi: retro - reverse transcription
• Morphology:
  
  • Diploid
  • +ssRNA genome
  • Helical + icosahedral capsid
  • Enveloped
• Resistance: very sensitive viruses
• Biological properties:
  
  • Baltimore VI. – viral reverse transcriptase → forms a pro-virus
  • If the cell divides, viral genome is also transmitted, leading to a life-long infection
• Genetic structure:
  
  • 5’-LTR-gag-pro-env-pol-LTR-3’
  • +/- oncogenic substitution mutant → a transforming, defective virus
  • Oncogenic: transforming viruses need helpers for multiplication
• Multiplication competent viruses: strong CPE, oncogenic as well
• Transmission: “Vertical route”: sex, placenta, etc.
• Antigenic properties:
  
  • ​Good antigens
  • Hypervariable surface antigens, Ig-s are not effective against integrated virus, destruction of the immune-system
  • Cross-reactions: specificity of antigens (core<capsid></capsid>
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• Diagnosis:
  
  • ​Clinical signs
  • Direct: ELISA, IF, PCR, NA hybridization
  • Indirect: ELISA, AGID (Coggins-test -EIA)

Question 2

Retroviridae

List the subfamilies and their genera

Answer 2

• Orthoretrovirinae
  
  • ​Alphavirus genus
  • Betavirus genus
  • Gammavirus genus
  • Deltavirus genus
  • Epsilonretrovirus genus
  • Lentivirus genus
• Spumaretrovirinae​
  
  • ​Spumavirus genus

Question 3

Retroviridae

Orthoretrovirinae​: alphavirus genus

Answer 3

• Avian leucosis virus
  
  • ​Chicken
  • Leukemia, lymphatic tumors
• Avian sarcoma
  
  • Chicken: fast developing mesenchymal tumours

Question 4

Retroviridae

Orthoretrovirinae​: betaretrovirus genus

Answer 4

• Ovine pulmonary adenocarcinoma virus
  
  • ​Sheep
  • Lung cancer
• Mouse mammary tumor virus
• Monkey retrovirus

Question 5

Retroviridae

Orthoretrovirinae​: gammaretrovirus genus

Answer 5

• Mammalian group:
  
  • Feline leukemia /sarcoma virus
• Reptilian group
• Avian group

Question 6

Retroviridae

Orthoretrovirinae​: deltavirus genus

Answer 6

• Bovine leukemia virus
  
  • ​Cattle
  • Leucosis
  • Slow-developing lymphatic tumors
• Human T-lymphotropic virus 1-2
  
  • ​Human T-cell leukemia
  • Sexually transmitted
  • Caribbean
• Primate T-lymphotropic virus

Question 7

Retroviridae

Orthoretrovirinae​: epsilonretrovirus genus

Answer 7

Fish virus

• Walley dermal sarcoma virus
• Walley epidermal hypoplasia virus

Question 8

Retroviridae

Orthoretrovirinae​: lentivirus genus

Answer 8

• Etymologi: lentus: slow
• Rarely cause tumors
• Immuno suppressive
• Equine infectious anaemia virus
  
  • ​Horse
  • Anemia
  • Lethal
• Maedi-Visna virus
  
  • ​Sheep
• Caprine arthritis - encephalitis virus
  
  • ​Goat
• Human immunedeficiency virus: HIV 1-2
  
  • ​T-helper cell destruction
  • Immunosuppression
  • AIDS: acquired immune deficiency syndrome
  • Can have virus but show no symptomse
    
    • Some resistance (low in Africa)

Question 9

Retroviridae

Spumaretrovirinae: spumavirus genus

Answer 9

• Etymologi: spuma: foamy
• Bovine foamy virus
  
  • ​Orphan?
• Feline-, Equine-, Simian-, Chimpanzee foamy virus