Flaviviridae

Question 1

most important genus for vet medicine

Answer 1

Pestivirus

Question 2

general characteristics flaviviridae

Answer 2

spherical virion, replication in cytoplasm

Question 3

two biotypes of Bovine Viral Diarrhea Virus (BVDV)

Answer 3

Non cytopathic and cytopathic

Question 4

BVDV Noncytopathic-

Answer 4

uncleaved NS2-3, doe snot induce apoptosis, most common, cross placenta, invade fetus, persistent in calves
-can cause congenital, repro or enteric disorders

Question 5

BVDV Cytopathic

Answer 5

arise from mutation of ncp biotype in persistently infected calves, non structural protein NS3 by cleavage of NS2-3, induce apoptosis, mucosal disease in cattle with persistently infected with ncp biotype

Question 6

mechanism of conversion of ncp or noncytopathic

Answer 6

inserts cellular sequences into NS2-3 gene of BvDV genomes leads to additional cleavage so NS2-3 and release NS3

Question 7

genotypes of BVDV

Answer 7

type 1 or 2, 1 is more detected than two, both 1 and 2 can have both biotypes

Question 8

BVDV in non pregnant cow

Answer 8

mild infection, scours, milk drop, reduced WBCs

Question 9

BVDV in pregnant first month

Answer 9

embryonic death

Question 10

BVDV in 2-4 months of pregnancy

Answer 10

persistent infection in calves

Question 11

BVDV months 5-9 of pregnancy

Answer 11

abortion early, then deformities, followed by no affect in late term

Question 12

persistent infection progressed to mucosal disease

Answer 12

persistently infect calves (PI) can show decreased weight gain and stunted growth and will continuously shed virus into environment
with 2 outcomes
1. will survive, shed virus, and develop antibodies to both biotypes
2. will be infected with super antigen or mutation occurs where calf doesn’t recognize cytopathic strain as foreign (no production)-> mucosal disease

Question 13

PI calves

Answer 13

main source of BVDV direct contact transmission because of constant shedding

Question 14

BVDV infection in Immunocompetent non-pregnant cattle

Answer 14

subclinical, diarrhea

Question 15

BVDV immunocompetent pregnant cattle

Answer 15

conception failure, embryonic mortality, abortion, fetal mummification, stillbirths, congenital defects, birth of stunted or PI calves

Question 16

BVDV immunotolerent cattle

Answer 16

mucosal disease (acute, chronic), appear ill and weak, secondary infection susceptibility

Question 17

congenital defects from BVDV

Answer 17

abortion, cerebral hypoplasia, stargazing, porencephaly, hydroencephaly (dome head), rigid joints

Question 18

mucosal disease BVDV acute form

Answer 18

ulceration of tongue, ulcerated nose and mouth, runny nose, ulcerations in gum, diarrhea, esophageal erosion, rumen ulceration, hemorrhagic focal lesions in abomasum, erosions and necrosis of peyers patches

Question 19

mucosal disease chronic BVDV

Answer 19

diarrhea, inappetence, emaciation, rough hair, chronic bloat

Question 20

BVDV diagnosis of PI calves

Answer 20

PCR on pooled skin samples, skin IHC, skin ELISA, SNAP BVD

Question 21

Hog Cholera (CSF) or Classic Swine Fever

Answer 21

caused by Pestivirus, indistinguishable from African Swine Fever, related to BVD, one antigenic version infecting pigs domestic or wild, OIE List A disease

Question 22

CSF distribution

Answer 22

not in USA since 1978, South America and Far East Asia, Except Japan and Korea

Question 23

CSF transmission

Answer 23

direct contact, fecal oral, aerosol, fomites, vets and farm workers, feeding garbage. healthy pig can inhale, ingest or get by insemination. Shed in urine and nasal discharge

Question 24

Path CSF

Answer 24

comes in through tonsil->peyers patches->early immunosuppression, depletion of CD1, CD4, CD8; macrophage activation and release of proinflamm cytokines; degeneration of vascular epithelium, thrombosis, hemorrhages; release of TNF-alpha in virus affected lymph nodes and apoptosis of lymphocytes; B-cells deficiency due to destruction of germinal centers of lymphoid tissues

Question 25

Peracute and acute forms of CSF show

Answer 25

hyperemia, huddling infections, cyanosis of ears, blotchy purple skin, diarrhea, hemorrhage in urinary bladder, turkey egg kidneys, button ulcer colon, abortion or stillbirth, nervous signs-running or goose stepping

Question 26

Dx for CSF

Answer 26

ELISA used most often

Question 27

CSF control

Answer 27

OIE list A notifiable disease, quarantine farms, slaughter and proper disposal of carcass, such as incineration, **avoid feeding uncooked garbage and meat products to pigs

Question 28

West Nile Virus

Answer 28

mosquito borne in genus flavivirus,endemic to africa australia, asia, the middle east, and europe

Question 29

WNV transmission

Answer 29

birds are reservoirs, blood transfusions, breast feeding, lab accidents, organ transplants, and intrauterine all ways to transmit

Question 30

WNV lineages

Answer 30

7 exist, only lineage 1 and 2 are affecting humans (1a)

Question 31

clinical forms of WNV in humans

Answer 31

fever, cutaneous, no neuro (myocarditis, hepatitis, nephritis) and neuro-WNE West Nile enceph., WNM West Nile Meningitis, and meningoencephalitis

Question 32

WNV signs in horses

Answer 32

mostly asymptomatic, 8% develop neuro, encephalomyelitis with ataxia are predominant clinical signs

Question 33

Louping ILL

Answer 33

tick bourne, zoonotic , viral in sheep, and red grouse, caused by flavivirus, 4 subtypes, found in british isles , ioxides ricinus

Question 34

louping ILL transmission

Answer 34

tick at any stage is infective

Question 35

loupe ILL path and clinical signs

Answer 35

replication of virus in brain, severe inflammation of CNS, necrosis of brainstem and ventral horn neurons, affected stand apart, may have ataxia, muscle tremors, lack of coordination, jerky