32 - Togaviridae, Flaviviridae, Hepeviridae

Question 1

Togaviridae

Answer 1

• Etymology: roman mantle, cloak
• Morphology:
  
  • ​Linear, +ssRNA genome
  • Icosahedral capsid
  • Enveloped
• Resistance: weak (37°C, pH 6-8)
• Biological properties:​
  
  • Baltimore IV.
  • CPE ø, HA
  • Alphavirus – zoonosis
    
    • Arboviruses – mosquito transmission
• Antigenic properties:
  
  • ​Good antigens
  • Cross-reactions within genera
• Diagnosis:
  
  • ​Clinical signs, IF
  • Serology: ELISA, IF, VN, HAI

Question 2

Togaviridae

List the different genera

Answer 2

• Alphavirus genus
• Rubivirus genus

Question 3

Togaviridae

Alphavirus genus

Answer 3

• Alpha: group A arboviruses
• Eastern, Western, Venezuelan equine encephalitis
  
  • Horse, human
  • America: CNS signs
• Chikungunya (Africa, India, Indonesia)
  
  • Human
  • Joint pains, fever, rash, hemorrhage
• O’nyong nyong (Africa)
  
  • Human
  • Fever, rash
• Ross river fever (Australia, New Guinea, Fiji)
  
  • Human
  • Fever, arthritis, rash
• Getah virus (South-East Asia)
  
  • Horse encephalitis (Japan)
• Sindbis virus (Africa, Mediterranean, Scandinavia)
  
  • Human: Ockelbo, Pogosta disease, Karelian fever
• Semliki forest virus (Africa)

Question 4

Togaviridae

Rubivirus genus

Answer 4

• Etymology: Rubeus: red - rash
• Rubella
  • Human – fever rash
  • Fetopathy: deafness, blindness, mental retardation

Question 5

Flaviviridae

Answer 5

• Etymology: flavus: yellow
• Morphology:
  
  • ​Linear +ssRNA genome
  • Icosahedral capsid
  • Enveloped
• Resistance: weak (37°C, pH 6-8; Pestivirus: pH 3-9)
• Biological properties:
  
  • ​Baltimore IV. – single polyprotein precursor
  • CPE: not typical or no, Flavivirus: HA
  • Flavivirus:
    
    • Arboviruses: mosquito or tick
    • Zoonoses: fever, hemorrhage, rash, encephalitis, hepatitis
• Antigenic properties:
  
  • ​Good antigens
  • Cross reaction within genera
• Diagnosis:
  
  • Clinical sings, histopathology, IF, PCR
  • Serology: ELISA, IF, PRNT

Question 6

Flaviviridae

List the different genera

Answer 6

• Flavivirus genus
• Pestivirus genus
• Hepacivirus genus
• Pegivirus genus

Question 7

Flaviviridae

Flavivirus genus

Answer 7

• Tick borne encephalitis viruses (human, goat – Europe, Asia)
• Louping ill (sheep meningoencephalitis – Europe)
• Yellow fever (human – tropics)
• Dengue fever (1-4) – (human – Asia, Africa)

Question 8

Flaviviridae

Pestivirus genus

Answer 8

Etymology: pest

• Classical swine fever
  
  • Swine
  • Haemorrhage, fever
  • High morbidity and mortality
• Bovine viral diarrhoea (BVD)
  
  • Calf diarrhoea, immunosuppression, tolerated infections
  • Mucosal disease
  • Fatal
• Border disease
  
  • ​Sheep fetopathy

Question 9

Flaviviridae

Hepacivirus genus

Answer 9

• Hepar C
• Hepatitis C virus​
  
  • Human serumhepatitis
• Chronic infection, cirrhosis
• „Non-primate hepaciviruses”
  
  • Canine hepacivirus
  • Equine hepacivirus

Question 10

Flaviviridae

Pegivirus genus

Answer 10

• Persisting, G
• Hepatitis G
  
  • ​Human
• Horse, bat, chimpanzee, rodent pegiviruses

Question 11

Hepeviridae

Answer 11

• Morphology:
  
  • ​Linear +ssRNA genome
  • Icosahedral capsid
  • No envelope
• Resistance: good
  
  • Senisitve to cold and iodine disinfectants
• Biological properties:
  
  • ​Baltimore IV: subgenomic mRNA-s
  • Stenoxen: genetrically host specific, but some are zoonotic
• Antigenic properties:
  
  • ​Good antigens
  • No vaccines
• Diagnosis:
  
  • ​Isolation: complicated
  • ELISA, RT-PCR

Question 12

Hepeviridae

List the different genera

Answer 12

• Orthohepvirus genus
• Piscihepevirus genus

Question 13

Hepeviridae

Orhohepevirus genus

Answer 13

• Hepatitis E: human acute hepatitis​
  
  • A, B: water borne, developing countries
  • C, D: swine, ruminant, rabbit reservior, world-wide

Question 14

Hepeviridae

Piscihepevirus genus

Answer 14

Chicken: hepatitis-splenomegaly