Flaviviridae

Question 1

Flaviviridae
enveloped or non-enveloped
RNA or DNA

Answer 1

enveloped
+ssRNA

Question 2

West Nile Virus
host:
amplification host:
dead end host:
transmission:
pathogenesis:
clinical signs:
zoonotic?
reportable?

Answer 2

host: birds, primates, horses
amplification host: birds
dead-end host: humans, horses
transmission: Culex mosquitos
pathogenesis: keratinocytes, Langerhans cells, DC; disseminates to spleen, crosses BBB
clinical signs:
birds - sudden death, crows/magpies/jays/raptors higher mortality than passerines w/ no clinical disease
humans/horses - encephalomyelitis/CNS signs (mortality higher in horses)
zoonotic
reportable

Question 3

which virus is the leading cause of arbovirus encephalitis in humans and horses

Answer 3

west nile virus

Question 4

West Nile Virus
diagnostics:
control:

Answer 4

diagnostics: IgM ELISA preferred over PCR for acute infections
control: mosquito control, vx for horses only

Question 5

Japanese Encephalitis Virus
dead end host:
amplification host:
transmission:
clinical signs:
diagnostics:
control:
reportable?
zoonotic?

Answer 5

similar to WNV, but Asia/Australia
dead-end host: humans, horses
amplification host: pigs, aquatic birds
transmission: Culex & Aedes mosquitos
clinical signs: encephalitis
diagnostics: PCR, ELISA
control: mosquito control, vx for humans
reportable
zoonotic

Question 6

Yellow Fever Virus
host:
transmission:
clinical signs:
diagnostics:
control:
reportable?
zoonotic?

Answer 6

host: non-human primates
transmission: mosquitos
clinical signs: hemorrhagic disease
diagnostics: ELISA, PCR
control: mosquito control, human vx
reportable
zoonotic

Question 7

what are the three Pestiviruses

Answer 7

1. bovine viral diarrhea virus
2. classical swine fever virus
3. border disease virus

Question 8

Bovine Viral Diarrhea Virus
host:
reservoir:
transmission:

Answer 8

host: wild & domestic ruminants & pigs
reservoir: PI calves
transmission: nasal secretions, saliva, milk, blood, mechanical, iatrogenic, fomites, in-utero, fecal-oral

Question 9

BVDV
biotypes?
genotypes?
tropism for?
typically results in?

Answer 9

non-cytopathic biotype (most common)
cytopathic biotype (cytopathic effect “CPE”)
genotypes: Type 1a, 1b, Type 2a, 2b
rapidly dividing cells (lymphocytes, monocytes, macrophages, epithelial cells)
immunosuppression

Question 10

what are the 3 types of infections of BVDV

Answer 10

1. acute infection in immunocompetent cattle
2. fetal infection in immunocompetent pregnant cattle
3. mucosal infection in immunotolerant cattle

Question 11

clinical signs of acute BVDV

Answer 11

BRDC & pneumonia
hemorrhagic syndrome
immunosuppression

Question 12

clinical signs of fetal infection in BVDV

Answer 12

embryonic death, abortion, stillbirth, congenital defects
seropositive calves
PI calves that are unthrift & prone to secondary infections or are normal and enter breeding/feed lots

Question 13

what results in a PI calf in BVDV

Answer 13

pregnant cow infected with the non-cytopathic biotype during 80-125 days (2-4mo) of gestation

Question 14

what congenital defect is typically associated with fetal infection of BVDV

Answer 14

cerebellar hypoplasia

Question 15

how does mucosal infection of BVDV occur

Answer 15

PI animal with endogenous non-cytopathic strain infected with cytopathic strain via spontaneous mutation or ML vx

Question 16

clinical signs of mucosal infection of BVDV

Answer 16

fever, anorexia, diarrhea, dehydration, ulcers, necrosis, hoof inflammation, enteritis, gross lesions, 100% fatal

Question 17

diagnostics of BVDV

Answer 17

IHC from ear notch (test of choice)
PCR
ELISA

Question 18

treatment and control of BVDV

Answer 18

treatment: supportive care
control:
vx - cytopathic biotype in ML vx (don’t give pregnants)
test/cull PI animals
biosecurity

Question 19

viral components of BRDC

Answer 19

bovine herpesvirus 1
bovine viral diarrhea virus
bovine resp syncytial virus
parainfluenza 3
bovine resp coronavirus

Question 20

Classical Swine Fever Virus
host:
transmission:
pathogenesis:
clinical signs:

Answer 20

host: domestic/wild swine
transmission: oronasal, ocular secretions, urine, feces, blood, semen, fomites, uncooked swill
pathogenesis: monocytes, macrophages, endothelial cells
clinical signs: “hog cholera”, hemorrhagic disease, cyanosis, splenic infarcts, button ulcers, turkey egg kidney
- acute (constipation or diarrhea)
-chronic (poor repro)

Question 21

Classical Swine Fever Virus
diagnostics:
control:
reportable?

Answer 21

diagnostics: PCR (esp tonsil), ELISA
control: vx, biosecurity, movement restrictions, quaratine, surveillance, not feeding swill
reportable

Question 22

why can classical swine fever virus have false + on ELISA

Answer 22

swine can also be infected with BVDV and border disease virus

Question 23

Border Disease Virus
host:
transmission:
clinical signs:

Answer 23

host: sheep, goats, cattle
transmission: secretion, vertical
clinical signs: “hairy shaker” or “fuzzy lambs”
acute - asymptomatic
fetal infection - CNS, fleece abnormalities, small/weak at birth, congenital defects, PI lambs

Question 24

how do PI lambs occur in border disease virus

Answer 24

pregnant ewes infected with non-cytopathic BDV before 60 days of gestation

Question 25

border disease virus
diagnostics:
control:

Answer 25

diagnostics: PCR (pan-pestivirus BDV & BVDV) or ELISA
control: no vx, test/cull PI animals, biosecurity