Flaviviridae Flashcards
Flaviviridae
enveloped or non-enveloped
RNA or DNA
enveloped
+ssRNA
West Nile Virus
host:
amplification host:
dead end host:
transmission:
pathogenesis:
clinical signs:
zoonotic?
reportable?
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
which virus is the leading cause of arbovirus encephalitis in humans and horses
west nile virus
West Nile Virus
diagnostics:
control:
diagnostics: IgM ELISA preferred over PCR for acute infections
control: mosquito control, vx for horses only
Japanese Encephalitis Virus
dead end host:
amplification host:
transmission:
clinical signs:
diagnostics:
control:
reportable?
zoonotic?
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
Yellow Fever Virus
host:
transmission:
clinical signs:
diagnostics:
control:
reportable?
zoonotic?
host: non-human primates
transmission: mosquitos
clinical signs: hemorrhagic disease
diagnostics: ELISA, PCR
control: mosquito control, human vx
reportable
zoonotic
what are the three Pestiviruses
- bovine viral diarrhea virus
- classical swine fever virus
- border disease virus
Bovine Viral Diarrhea Virus
host:
reservoir:
transmission:
host: wild & domestic ruminants & pigs
reservoir: PI calves
transmission: nasal secretions, saliva, milk, blood, mechanical, iatrogenic, fomites, in-utero, fecal-oral
BVDV
biotypes?
genotypes?
tropism for?
typically results in?
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
what are the 3 types of infections of BVDV
- acute infection in immunocompetent cattle
- fetal infection in immunocompetent pregnant cattle
- mucosal infection in immunotolerant cattle
clinical signs of acute BVDV
BRDC & pneumonia
hemorrhagic syndrome
immunosuppression
clinical signs of fetal infection in BVDV
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
what results in a PI calf in BVDV
pregnant cow infected with the non-cytopathic biotype during 80-125 days (2-4mo) of gestation
what congenital defect is typically associated with fetal infection of BVDV
cerebellar hypoplasia
how does mucosal infection of BVDV occur
PI animal with endogenous non-cytopathic strain infected with cytopathic strain via spontaneous mutation or ML vx
clinical signs of mucosal infection of BVDV
fever, anorexia, diarrhea, dehydration, ulcers, necrosis, hoof inflammation, enteritis, gross lesions, 100% fatal
diagnostics of BVDV
IHC from ear notch (test of choice)
PCR
ELISA
treatment and control of BVDV
treatment: supportive care
control:
vx - cytopathic biotype in ML vx (don’t give pregnants)
test/cull PI animals
biosecurity
viral components of BRDC
bovine herpesvirus 1
bovine viral diarrhea virus
bovine resp syncytial virus
parainfluenza 3
bovine resp coronavirus
Classical Swine Fever Virus
host:
transmission:
pathogenesis:
clinical signs:
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)
Classical Swine Fever Virus
diagnostics:
control:
reportable?
diagnostics: PCR (esp tonsil), ELISA
control: vx, biosecurity, movement restrictions, quaratine, surveillance, not feeding swill
reportable
why can classical swine fever virus have false + on ELISA
swine can also be infected with BVDV and border disease virus
Border Disease Virus
host:
transmission:
clinical signs:
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
how do PI lambs occur in border disease virus
pregnant ewes infected with non-cytopathic BDV before 60 days of gestation
border disease virus
diagnostics:
control:
diagnostics: PCR (pan-pestivirus BDV & BVDV) or ELISA
control: no vx, test/cull PI animals, biosecurity
