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422 Virology > lecture 8- small ruminant virology > Flashcards

lecture 8- small ruminant virology Flashcards

1
Q

what is it called when viruses have the ability to change a normal cell into a tumor cell? what are these viruses referred to as

A

transformation
oncogenic viruses

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2
Q

what are the 2 groups of tumor genes

A

proto oncogenes
tumor suppressor genes

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3
Q

what are the oncogene DNA viruses (6)? what do they encode?
what part of the cell cycle do they affect?

A

pox
herpes
adeno
papilloma
polyoma
depadna

encode inhibitors of tumor suppressor genes

affects the end of M / beginning of G1

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4
Q

what are the oncogene RNA viruses (2)? what do they encode?
what part of the cell cycle do they affect?

A

retro
flavi

encode homologs of oncoproteins

between G1 and S phase

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5
Q

what is JSRV? What does it cause?

A

Jaagsiekte sheep retrovirus

the agent that causes ovine pulmonary adenocarcinoma

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6
Q

what is OPA

A

ovine pulmonary adenocarcinoma

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7
Q

what cells does ovine pulmonary adenocarcinoma (OPA) target?

A

epithelial cells of bronchioli and alveoli (type 2 pneumocytes), lymphocytes, myeloid cells

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8
Q

what is JSRVs (Jaagsiekte sheep retrovirus) mechanism of action?

A

is a retrovirus and carries and oncogene (inserts into host genome)

it is a ssRNA-RT

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9
Q

what is the structure of JSRV? (Jaagsiekte sheep retrovirus)

A

enveloped, positive sense

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10
Q

what is the geographical distribution of ovine pulmonary adenocarcinoma (OPA)/JSRV

A

everywhere but australia, iceland and new zealand

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11
Q

at what age are most animals infected with JSRV?

A

over 2 years, peak at 3-4 years

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12
Q

is JSRV always fatal once clinical signs appear?

A

yes

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13
Q

how is JSRV transmitted?

A

respiratory (aerosole/droplets), milk/colostrum

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14
Q

once infected with JSRV, can sheep get rid of the virus?

A

no! retrovirus so carriers for life

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15
Q

what are the clinical manifestations of OPA/JSRV

A

fever, cough, dyspnea;
chronic resp signs (2-4 YO
animals) with frothy mucoid
discharge from nostrils

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16
Q

if a sheep is infected with JSRV/OPA, what will be seen on histo

A

proliferating type 2 pneumocytes

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17
Q

what will be seen grossly with OPA on necropsy?

A

frothy fluid filling trachea/nares
enlarged, edematous lunge that fail to collapse (interstitial pneumonia)
focal to diffuse bulky mass (tumors)
enlarged lymph nodes

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18
Q

explain how the wheel barrow test might help with diagnosing OPA

A

raising hind legs will cause excess lung fluid to drain from nose/mouth.

this is because type 2 pneumocytes are proliferating, thus producing toooooo much surfactant (yuck)

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19
Q

why is there not a vaccine for JSRV?

A

approx 20 copies of endogenous JSRV are already encoded into sheep genome, so making a vaccine that only targets the virus would be very difficult! it might also cause autoimmune inflammatory reactions

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20
Q

is quarantining sheep that are suspected to have OPA a practical control solution?

A

noooope - incubation is 6 months - 3 years so not realistic

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21
Q

what virus causes ovine progressive pneumonia? (OPP)

A

maedi-visna virus

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22
Q

what kind of virus is maedi visna virus (MVV)

A

lentivirus (retrovirus)

23
Q

if you break it down, what do maedi and visna mean?

A

maedi- dyspnea
visna- neurologic

24
Q

true or false: most sheep infected with MVV are subclinical

A

true! despite the name, usually sheep do not get respiratory and especially not neuro signs

though they sometimes do!!

25
Q

how is MVV transmitted?

A

respiratory, colostrum, sexual

26
Q

what cells does MVV target?

A

monocytes/macrophages and dendritic cells

27
Q

you are doing a necropsy on a sheep and when you open the chest you notice that the lungs fail to collapse and are covered in coalescing multifocal gray-white nodules with adjacent atelectic depressions. what is your top differential? what is the virus that causes this disease?

A

ovine progressive pneumonia caused by maedi visna virus

28
Q

can PCR diagnose MVV?

A

nooooo its a ssRNA-RT so must to RT-PCR

29
Q

what is the structure and replication strat of OPP/MVV

A

enveloped , positive sense
ssRNA-RT

30
Q

what is CAE

A

caprine arthritis and encephalitis

31
Q

what virus type causes caprine arthritis and encephalitis (CAE)

A

a lentivirus

32
Q

what are the 4 clinical signs of CAE? what is most likely?

A
  1. polyarthritis in adults (get swelling at the carpus (with/out pain) and
    thickening in and around
    joints –> proliferative and
    fibrinous synovitis)
  2. encephalomyelitis in kids (sometime adults)
  3. indurative mastitis from lymphatic infiltration (decreased milk production)
  4. chronic interstitial pneumonia

usually subclinical!! (80%)

33
Q

what species does CAE infect

A

sheep and goats

34
Q

how is CAE transmitted

A

colostrum and milk

35
Q

what cells does CAE target?

A

macrophages, dendritic cells, synovial membrane cells

36
Q

you go to a farm and there are young goats with encephalitis, ataxia, and an inability to adduct their hind limbs. The adult goats have arthritis and weight loss, as well as poor coats. what is your top differential? how would you test for this?

A

caprine arthritis / encephalitis!!!

take blood and do a AGID test and ELISA

37
Q

how fo you control for CAE?

A

prevent vertical transmission
use AGID tests to test for virus, and if there are 2 negative tests 6 months apart then youre probs safe

38
Q

what is another name of orf?

A

contagious ecthyma , sore mouth, scabby mouth

39
Q

what kind of virus is orf

A

poxvirus! in family poxviridae

40
Q

which species are primarily infected by orf

A

sheep and goats!

also alpacas, muskoxen, bighorn sheep, dogs, zoonotic***

41
Q

what does orf target

A

skin and oral mucosa

epithelial cells and keratinocytes

42
Q

what is a typical histological observation with orf?

A

epithelial hyperplasia- ballooning degeneration of epithelial cells

43
Q

is the orf vaccine super cool and awesome?

A

NO - there are so many adverse effects!!

including: animals developing lesions and being able to shed the virus, the vaccine can infect humans, AND it doesnt even produce long lasting immunity

44
Q

what kind of virus is blue tongue? from which family

A

blue tongue is a orbivirus from the family Reoviridae

45
Q

what species does blue tongue affect

A

sheep*, cattle, deer, goats, camilids

46
Q

are there lots of strains of blue tongue?

A

yessir, up to 27 strains but there is poor cross protection stability

47
Q

how is blue tongue transmitted? what does this mean regarding geography?

A

biting midges! from the genus Culicoides

canada is currently free, but climate change might change vector range

48
Q

a farmer in Mexico calls you up to check out some sheep that he claims arent doing well. when you arrive and examine them, you note they are fibril, have ocular and nasal discharge, are drooling from ulcerated mouths, have swollen mouth, head, and necks, and are having difficulty breathing. what is your top differential?

A

blue tongue!!! this is an orbivirus

49
Q

which serotype of blue tongue causes abortion and/or neurological signs in lambs

A

serotype 8 :(

50
Q

what is special about cattle infected with bluetongue ?

A

they will be persistently infected with one strain, but will not show clinical signs until they are infected with more than one strain

the signs they get are:ulcers, lameness, hoof cracks, hair loss, and swollen tongue

51
Q

which small ruminant viruses are in the family retroviridae (3)? which genus is each?

A

ovine maedi visna virus - lentivirus group A
caprine arthritis and encephalitis virus - lentivirus group B
jaagsiekte sheep retrovirus / ovine pulmonary adenomatosis virus - betaretrovirus

(also enzootic nasal tumor virus - betaretrovirus)

52
Q

which small ruminant virus is a part of the family Reoviridae? which genus is it in?

A

blue tongue virus - orbivirus

(also ovine rotavirus - rotavirus)

53
Q

which small ruminant viruses are in the family Poxviridae (2)? which genus is each?

A

orf virus -parapoxvirus
sheep and goat pox biruses - capripoxvirus

422 Virology (15 decks)

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