L28: Flaviviridae: Pestiviruses (Romero)

Question 1

Bovine viral diarrhea virus chars.

Answer 1

• heterogenous group of related viruses
• causes Bovine viral diarrhea (an acute epizootic infection) and Mucosal disease (a spordic lethal enzootic disease of persistently-infected bovines)

Question 2

Bovine viral diarrhea virus susceptible hosts

Answer 2

• cattle
• buffalo
• antelope
• llamas, alpacas

Question 3

Epi of Bovine viral diarrhea virus

Answer 3

• non-pregnant cattle: mostly calves
• pregnant cattle: transplacental infection to embryo/fetus
• persistent infection in calves and mucosal disease

Question 4

Path. of Bovine viral diarrhea virus

Answer 4

• replicates in nasal mucosa/tonsils
• spreads to regionl LN and systemically
• most infections subclinical
• causes ulcerative lesions throughout GIT

Question 5

Trans. of Bovine viral diarrhea virus

Answer 5

• respiratory, fomites, secretions, placental tissues
• poor trans. from acutely-affected animals
• persistently-infected bovines are life-long shedders
• in utero infections have varying consequences depending on age of fetus (younger may cause abortion, while older causes malformation)

Question 6

Mucosal disease

Answer 6

• caused by dual infection of cytopathic and non-cytopathic biotypes of BVDV (cytopathic biotype is generated from bovines persistently infected with non-cytopathic biotype)
• study lect. 27 for the rest of info on this*

Question 7

BVDV is what type of virus?

Answer 7

Pestivirus and Rotavirus

Question 8

What genera of viruses are contained within Paramyxoviridae?

Answer 8

viruses of utmost veterinary importance
Paramyxovirinae (ex. Morbilliviruses (canine distemper))
Pneumovirinae

Question 9

Paramyxoviridae enveloped?

Answer 9

yes

Question 10

Hemagglutinin (H) used for:

Answer 10

viral attachment; neutralizing Ab made mostly against H

Question 11

Fusion (F) protein fx

Answer 11

• mediates viral entry via fusion of virion and cell memb.
• cell-mediated immunity
• mediates fusion with other cells during replication

Question 12

Canine distemper chars.

Answer 12

• highly contagious
• uncommon in US/Europe
• dogs, foxes, racoons, ferrets, etc.

Question 13

7 lineages of canine distemper virus based on Hemagglutinin gene**

Answer 13

Asia-1
Asia-2
America-1
America-2
Arctic-like
Europe
European wildlife

Question 14

CS of Canine Distemper

Answer 14

• variable, depending on strain/host
• 50% infections sub-clinical
• Mild distemper: fever, ocular secretions, cough
• Sever distemper: fever, leukopenia, depression, bacterial infection, bronchopneumonia, encephalitis

Question 15

CNS involvement of canine distemper

Answer 15

neuro signs occur 1-3wks after onset of acute signs

• poor prognosis
• progressive
• survivors develop sequelae

Question 16

Trans. of canine distemper

Answer 16

• shed in all secretions, even before onset of CS
• mainly by resp. transmission by direct contact with infected droplets
• young very susceptible

Question 17

inclusion bodies of canine distemper

Answer 17

within neuts, lymphocytes

Question 18

Path. of canine distemper

Answer 18

• replicates in macs, then spreads to tonsils and regional LN
• lymphoid cells affected –> immunosuppression
• mononuclear cell viremia and systemic spread
• infection of epi. cells occurs late in infection

Question 19

Dx of canine distemper

Answer 19

• RT-PCR and sequencing of H gene** needed to distinguish vax from field viruses!
• virus isolation from lymphocytes
• histopath of lung/brain/bladder in dead animals
• serology

Question 20

immunity/prevention/control of canine distemper

Answer 20

• life long immunity
• control: vax and quarantine
• live-attenuated vax neutralized by maternal Ab
• Tx: Hyperimmune serum/Immunoglobulins post-exposure