Bovine Viruses (Lecture 4+5)

Question 1

Give 5 animals that can be a host for BVDV

Answer 1

Deer, rabbits, sheep, goats, pigs, (moose, llamas)

Question 2

what 4 criteria must an animal meet to be a reservoir of BVDV

Answer 2

Must be susceptible to BVDV
must shed the virus
must maintain BVDV in the pop
must have contact with cattle

Question 3

true or false, BVDV usually occurs in pigs with no clinical signs

Answer 3

true, if signs do show up its abortion, poor conception rates, still born

Question 4

If a cow is infected with BVDV at 1month gestation, 2-4months, and 5-9months, what are the outcomes?

Answer 4

1mon= early embryonic death and return to estrus
2-4mon= calf with persistent infection and antibody negative, possible abortion or malformation
5-9mon= able to recognize virus as nonself and establish antibodies and be normal, or possible abortion or malformation (blindness tremors)

Question 5

When is it most dangerous for a fetus to become infected with BVDV

Answer 5

60-120 days as they’ll become persistently infected and persistent shedders of the virus

Question 6

list the pathogenesis of BVDV

Answer 6

1. oronasal infection
2. tonsils
3. regional lymphnodes
4. blood circ
5. lymphoid tissue of gi tract and lungs
6. thymus bone marrow and spleen
   7 all other organs

Question 7

BLV infects

Answer 7

b lymphocytes

Question 8

infection of BLV leads clinically to

Answer 8

1. asymptomatic stage
2. persistent lymphocytosis
3. leukemia/lymphoma

Question 9

how does BLV transmit between animals

Answer 9

transmission of infected cells via

blood, colostrum, milk, in the uterus, breeding

Question 10

BRDC is associated with

Answer 10

winter and the first 40 days on feed

Question 11

what are the 4 important viruses associated with BRDC

Answer 11

1. BHV1
2. Bovine parainfluenza 3
3. bovine respiratory syncytial virus
4. BVDV

Question 12

describe the epidemiology of BRSV and BPIV3

Answer 12

spread through direct contact between animals and aerosols, 70% of infections happen in calves under 2 years old and humans are passive vectors

Question 13

describe the pathogenesis of BRSV and BPIV3

Answer 13

1. virus enters through the resp tract
2. damage to mucosa
3. invade epithelial cells of the resp tract
4. replicate in the resp tract
5. infect more animals through hosts snot

Question 14

which BRCV replicate well in the pulmonary alveolar macrophages

Answer 14

Bovine parainfluenza 3

Question 15

what causes the damage in cattle infected with BRSV? The virus itself or the bodies response to it?

Answer 15

the immune system- pro-inflammatory genes are upregulated and extensive mast cell degeneration

Question 16

true or false, BRSV is more pathogeneic in neonates compared to young calves (6 weeks)

Answer 16

false

Question 17

When does the peak clinical signs of BRSV occur

Answer 17

4-6 days after infection

Question 18

which is more severe BRSV or BPIV3

Answer 18

brsv

Question 19

Ovine herpes virus 2 infection in bovine has ____ mortality and ____morbidity

Answer 19

high, low

Question 20

what is the pathogenesis of BHV1

Answer 20

1. nose to nose contact or aerosols
2. enters epithelial and eventually nerve cells in the upper airway
3. lysis of infected cells
4. lysis of ciliated epithelium in the trachea limits primary innate defense

Question 21

BHV1 is excreted via snot for how many days? when most infectious

Answer 21

10-17 days, peak at 4-6 days

Question 22

how long will BHV-1 live in the environment for at 4deg, in frozen semen?

Answer 22

1 month, may survive more if in feed, in semen 1 yr

Question 23

which group of rotaviruses are the major cause of rotavirl infection in domestic animals

Answer 23

A

Question 24

BRV causes diarrhea in calves

Answer 24

1-2 weeks of age

Question 25

BRSV and BPIV3 are alike in pathogenesis and epidemiology list at least 2 differences between them

Answer 25

bovine parainfluenza virus replicates well in the pulmonary alveolar macrophages leading to phagocytosis and prostaglandin production suppressed , BRSV does not

In BRSV infection its the host immune system that causes damage thorough mast cell degeneration

BRSV is more pathogenic in young claves instead of new borns

BPIV3 is generally less severe

Question 26

what are the clinical outcomes of BHV infection

Answer 26

respiratory disease, infectious bovine rhinotracheitis, necrotic lesions on nasal and mucosal regions , abortions up to 100 days after infection, high morbidity, relatively low mortality

Question 27

How would you clean the environment of BHV

Answer 27

BHV is enveloped so it will be susceptible to detergents and natural solvents like acetone, ether and chloroform

Question 28

how does rotavirus cause diarrhea

Answer 28

rotavirus replicates in the enterocytes leading to osmotic diarrhea via altered metabolism of enterocyte membrane proteins. it also increases cell leakiness by increasing intracellular ca2+ disrupting the tight junctions

replicating virus produces a toxin which induces secretory diarrhea