Lecture 19: Flaviviruses

Question 1

answer kahoot

Answer 1

peyers patches

Question 2

answer kahoot

Answer 2

porcine parvovirus

Question 3

what is the morbidity and mortality differences between BVD and mucosal disease of BVD

Answer 3

BVD: high morbidity, low mortality
MD: low morbidity, high mortality

Question 4

what is the most economically important viral disease of cattle worldwide

Answer 4

BVDV

Question 5

BVDV 1 and 2 have __ and __ forms

Answer 5

cytopathic and non-cytopathic forms

Question 6

who does border disease virus infect and what does it cause

Answer 6

sheep- odd hair coat at birth, frail neurologic

Question 7

what are the two clinical forms of BVDV

Answer 7

1. Conventional
2. Mucosal disease

Question 8

what are the two variants of BVDV

Answer 8

1. Cytopathic
2. Non-cytopathic

Question 9

persistently infected animals with BVDV are infected __ and have __virus that later mutates into __

Answer 9

in utero, non-cytopathic virus, mutates into cytopathic virus

Question 10

is congenital BVD cytopathic or non-cytopathic

Answer 10

non-cytopathic

Question 11

what occurs if pregnant cow infected with BVD day 0-30 gestation

Answer 11

embryonic death, apparent infertility

Question 12

what occurs if pregnant cow infected with BVD day 30-150 gestation

Answer 12

abortion, congenital anomalies

Question 13

what occurs if pregnant cow infected with BVD days 30-90 gestation

Answer 13

persistent infection (non-cytopathic strain)

Question 14

what occurs if pregnant cow infected with BVD >150 gestation

Answer 14

no adverse effects

Question 15

what is pathogenesis of BVDV

Answer 15

1. Aerosol/ fecal transmission from persistently infected cattle
2. Oronasal exposure and replication in mucosa
3. Viremia- free or leukocyte associated
4. Immunosuppression: Lympho/leuko/ thrombocytopenia
5. Targets: enterocytes and lymphoid centers in gut, spleen, tonsils

Question 16

Animals exposed in utero days 30-60 gestation get __infection of BVDV before __, after __

Answer 16

persistent BVDV, before immunocompetence, after neural development

Question 17

t or f: persistently infected calves with BVDV form antibodies

Answer 17

false

Question 18

what is the primary source of infection in herds for BVDV

Answer 18

persistently infected cows

Question 19

mucosal disease of BVDV is mutation from __strain to __ strain

Answer 19

non-cytopathic to cytopathic strain

Question 20

what is the mutation that occurs to go from non-cytopathic BVDV to cytopathic

Answer 20

NS2/NS3–>NS3

Question 21

what is target of cytopathic strain of BVDV

Answer 21

GALT tissues/peyers patches

Question 22

how can you dx BVDV in persistently infected calves

Answer 22

ear notch antigen capture ELISA (ACE)

Question 23

how can you dx conventional infection with BVDV

Answer 23

FA on affected tissues, serology, PCR (unlikely ACE +)

Question 24

how does ear notch test work for BVDV

Answer 24

1. Primary antibody bound to plate
2. Ag from sample binds primary antibody
3. Secondary antibody binds antigen with color change

Question 25

what is most important control method for BVDV

Answer 25

identify and remove PI

Question 26

how is classical swine fever transmitted

Answer 26

uncooked swill and other pork products

Question 27

is there a vaccine for classical swine fever

Answer 27

no DIVA incompatible

Question 28

how is WNV transmitted

Answer 28

vector born- culex and seeds

Question 29

culex vectors prefer __

Answer 29

birds

Question 30

aedes vectors prefer __

Answer 30

mammals

Question 31

What is WNV life cycle

Answer 31

1. Birds increase viremia
2. Mosquitoes feed off birds
3. Mosquitoes transmit to horses and humans, decreased viremia (dead end hosts)

Question 32

t or f: horses are dead end hosts for WNV

Answer 32

true

Question 33

what is reservoir species for WNV

Answer 33

birds (especially Corvids)