Lecture 7; small ruminant viral infections

Question 1

what is it meant by virus induced transformation?

Answer 1

a virus has changed a normal cells into a tumor cell- these viruses are oncogenic viruses

Question 2

give 4 examples of oncogenic DNA viruses, and where do they disrupt the cell cycle

Answer 2

1. pox 2. herpes 3. adeno 4. papilloma

DNA oncogenic viruses interrupt the cell cylce at the start just after M because the encode inhibitors of tumor suppressor genes

Question 3

give 2 examples of RNA oncogenic viruses and where do they interrupt the cell cycle

Answer 3

1. retro 2. flavi

RNA oncogenic viruses encode homologs of oncoporteins so they act on the point of no return in G1

Question 4

The contagious lung tumor condition caused by Jaagsiekte retrovirus (JSRV) is called

Answer 4

Ovine pulmonary adenocarcinoma

Question 5

what 2 countries are free of OPA?

Answer 5

Australia and iceland

Question 6

what age are you going to see most clinical cases of OPA

Answer 6

3-4 year olds, rare in sheep under 7-9 months of age

Question 7

is OPA fatal?

Answer 7

yes, once clinical signs appear this disease is always fatal

Question 8

how is JSRV transmitted

Answer 8

respiratory route- aerosols or droplets (transmitted even by sub clinical animals) also through milk and colostrum

Question 9

describe the pathogenesis of OPA

Answer 9

1. infection via inhalation of virus 2. the epithelial cells of the lung are infected 3. virus is expressed and shed 4. transformation 5. tumor growth and spreads to the lymphnodes 6. death

Question 10

what is the incubation period for OPA

Answer 10

6-36 months

Question 11

what cells within the lung are transformed by JSRV

Answer 11

Type II pneumocytes are the majority, then club cells, then undifferentiated cells

Question 12

what will you see pathologically with OPA

Answer 12

frothy fluid filled trachea
intersitial pneumonia appearance
tumors
secondary abscessation
bronchial and mediastinal lymph nodes are often enlarged

Question 13

what are the clinical signs of OPA

Answer 13

fever cough dyspena frothy mucoid discharge (us the wheelbarrow test to check for extra fluid in the lungs)

Question 14

can you dx OPA? why or not why not?

Answer 14

Not with certainty- there will be lots of secondary bacterial infections, and antibodies are not detected in the sera- you may be able to detect through RT PCR of the bronchoalveolar cells

Question 15

what is the treatment option for OPA

Answer 15

Culling is really the only option- if vx is attempted it can induce autoimmune inflammatory response in the reproductive track and then break any tolerance they did have to the disease

Question 16

what is OPP and what virus causes it?

Answer 16

OVINE PULMONARY PNEUMONIA caused by maedi visna virus (retrovirus)

Question 16

how can a producer avoid OPA infection?

Answer 16

its hard- you cannot detect the subclinical animals and that is usually how it is introduced into a flock. make sure to get sheep from a farm with no hx of OPA and quarantine could be an option but again the incubation period is 6-36 months (not practical), mayne hand rear lambs, and have single aged flocks

Question 17

what are the signs and symptoms of OPP, how is it transmitted

Answer 17

dyspnea, neuro signs, poor milk production due to mastitis

transmitted via respiratory colostrum and sexual

Question 18

what cells are infected by OPP

Answer 18

macrophages and dendritic cells

Question 19

what gross lesions of the lung will you see with OPP

Answer 19

lungs that fail to deflate and contain coalescing multifocal gray nodules with adjacent atelecatic depressed parenchyma

Question 20

what clinical signs will you see with MVV infection

Answer 20

visna (neuro); brain and spinal cord infection, hind limb weakness ataxia, paresis and paralysis

maedi (dyspnea); arthritis, mastitis in addition to the resp involvement

Question 21

how would you dx and control OPP

Answer 21

DX; AGID- WESTERN blotting, RT- PCR

to control you can remove kids and lambs before they are fed colostrum but it can also be passed transplacental so that doesnt helo there

Question 22

what s CAE? what are its symptoms/ syndromes?

Answer 22

caprine arthritis and enceophalitis, it causes polyarthritis in adults and encephalomyelitis in kids, also causes indurative mastitis (hard udder) and decreases milk production, as well as chronic interstitial pneumonia

Question 23

how is CAE transmitted? by what virus? what cells are targeted

Answer 23

carprine arthritis and encephalitis is caused by infection of the CAE virus and is transmitted by vertical transmission via colostrum and milk, it targets macrophages and DC and synovial membrane cells

Question 24

clinically, what would you see in a goat that is infected by CAEV

Answer 24

edmatous thickening of the joints, chronic intersitial pneumonia, hard udder

Question 25

youre presented with a young kid that is ataxic and cannot move its hindlimbs, what is most likely OPA OPP or CAE

Answer 25

CAE

Question 26

how do you dx CAE, control?

Answer 26

AGID test, ELISA
no vx, no cure, prevent vertical transmission

Question 27

what is orf?

Answer 27

contagious ecthyma of sheep, caused by the orf virus (parapoxvius)

Question 28

what are the clinical symptoms of Orf? whats important to remember

Answer 28

orf is ZOONOTIC! causes scappy lesions around the mouth and nose, spread through direct contact or fomites

Question 29

what is the incubation period of Orf, is it fatal?

Answer 29

2-3 days, no uncomplicated infections resolve in 1-4 weeks it has high morbidity low mortality

Question 30

what cells are targeted with orf virus

Answer 30

epitheliotropic virus targets epidermal keratinocytes

Question 31

would you reccomend the orf vx?

Answer 31

no- it causes infection, spreads infection, and does not provide long lasting immunity (year long max)

Question 32

what is blue tongue, which animal is the main reservoir?

Answer 32

caused by the blue tongue virus it infects sheep cattle deer goats and camelids and cows are the mammalain resivores transmitted by culicoides

Question 33

what are the clinical signs of blue tongue in sheep

Answer 33

high temp, eye and nasal discharge, ulcers in the mouth, swelling of the mouth head a neck, lameness with inflammed coranary band, abortion, trouble breathing

Question 34

true or false, cattle that are persistently infected with one strain og BTV will show symptoms

Answer 34

false; they will not shoe clinical signs until they are infected with an additional strain and then you may see ulcers in the mouth nose and udder along with lameness and swollen tongue