lecture 15- equine virology Flashcards

1
Q

what strain of equine influenza still persists today? when did the other strain go away

A

today H3N8

H7N7 was last detected in 1977

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2
Q

how many types of influenza virus are there? which is of importance with horses?

A

4- A, B, C, D

A is of importance with horses

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3
Q

A1 is ___

A

H7N7

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4
Q

A2 is ___

A

H3N8

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5
Q

how is equine influenza transmitted?

A
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6
Q

true or false: shedding of infectious influenza virus from vaccinated horses is not possible

A

false - it is possible

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7
Q

what body system is infected by equine flu?

A

respiratory (ciliated epithelial cells and alveolar macrophages)

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8
Q

how are mares impacted by flu virus if they are pregnant?

A

can cause fetal loss due to fever/clinical signs (hypoxia) but NOT directly due to the virus itself

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9
Q

a group of horses presents with a fever, depression, inapp, conjunctivitis, serous discharge, dry/harsh cough

what are you concerned about

A

equine influenza

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10
Q

what sample type is best for confirming equine flu?

A

nasopharyngeal swabs, blood sampes

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11
Q

how does a hemagglutination inhibition test work to test for equine flu

A
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12
Q

how is PCR used in identifying the clade equine flu ? why is this important?

A

identify which strain of flu

different immune response

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13
Q

what is the modified live cold-adapted equine influenza vaccine? why is this significant? how is it administered?

A

vaccine strain is temperature sensitive and does not replicate at lower respiratory tract –> strong (and faster!) immunity at entrance of where virus would enter

can use at the face of an outbreak (unique!)

administered intranasal route

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14
Q

describe how marker / DIVA vaccines work in regards to equine flu

A
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15
Q

what is the main goal of DIVA vaccine strategy

A

differentiate between vaccinated and infected animals

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16
Q

if there is an inefficient buffer zone with regards to emergency vaccination, what happens if an individual is introduced that is not vaccinated

A

pathogen can escape the vaccination buffer

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17
Q

what is EVA

A

equine viral arteritis

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18
Q

EVA is a _____ notifiable disease

A

annually

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19
Q

the source of EVA is from…

A

the stallion

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20
Q

stallions are _____ carriers of EVA

A

long term

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21
Q

how is EVA transmitted

A

through breeding

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22
Q

true or false: mares can carry EVA

A

false!! stallions only

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23
Q

describe the pathogenesis of EVA

A
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24
Q

a mare aborts a fetus on a breeding farm…. what virus might you be concerned about

A

EVA

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25
Q

abortion is rare with EVA when transmitted by _____, but common with _____ transmission

A

rare with venereal transmission

common with aerosol transmission

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26
Q

horse presents with depression, edema*, nasal discharge, epiphora, and urticarial rash

what are you concerned about

A

EVA

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27
Q

how do viruses induce vasculitis (and thus edema)?

A
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28
Q

what is equine sarcoids caused by

A

bovine papilloma virus 1 and 2

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29
Q

how is equine sarcoids transmitted?

A

through fomites, but bovine must be present

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30
Q

true or false: equine to equine transmission of bovine papilloma virus is common

A

false- this is not possible

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31
Q

what are the gross forms of equine sarcoid?

A

nodular and verrucous form

fibroblastic form

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32
Q

what is seen histologically with equine sarcoid?

A

epidermal proliferation - long rete pegs into dermal fibroblastic tissue

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33
Q

you are a veterinarian in an equine practice in north america and presented with horses for vaccination against equine influenza. the subtype you chose to vaccinate is

A

E- H3N8

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34
Q

the cold adapted equine influenza vaccines are considered safe since…

A

the vaccine replicates only in the upper respiratory mucosa

35
Q

equine arteritis virus infection

A

reduces fertility in stallion

36
Q

equine sarcoids

A

cannot be cured

37
Q

what are the clinical manifestations of EHV- 1

A

Respiratory, abortion storm, encephalomyelitis

38
Q

what are the clinical manifestations of EHV- 2

A

No clinical signs but associated with keratoconjunctivitis

39
Q

what are the clinical manifestations of EHV- 3

A

Genital lesions (coital exanthema)

40
Q

what are the clinical manifestations of EHV- 4

A

Respiratory, but rare and isolated abortions

41
Q

what are the clinical manifestations of EHV- 5

A

Associated with equine multinodular pulmonary fibrosis

42
Q

which EHV’s are of the most significance?

A

1 and 4

43
Q

how is horse herpesvirus transmitted

A

acquire the infection by direct or indirect contact /short distance aerosols

44
Q

what is the incubation period of equine herpes virus?

A

1-10 days

45
Q

how can herpes virus be carried?

A

by blood (mainly leukocytes)
by lymph

46
Q

where does equine herpes replicate?

A

respiratory tract

47
Q

true or false: equine herpes does not impact repro tract, but does impact CNS

A

false- impacts both

48
Q

what body systems are impacted by equine herpes virus 1

A

respiratory, repro, neuro

49
Q

what equine viruses cause neurological manifestations? (6)

A

EHV-1
West Nile Virus
Eastern Equine Encephalitis
Western Equine Encephalitis
Venezuelan Encephalitis
Rabies

50
Q

what is the typical appearance of herpesviruses on histo

A

intranuclear, eosinophil inclusion bodies

51
Q

what samples are needed to diagnose equine herpesvirus? what tests will you run?

A

nasopharyngeal swab for PCR/virus isolation
EDTA blood for PCR/virus isolation
aborted tissue fetus for histology/immunostaining

52
Q

true or false: neurovirulence is strain specific

A

true

53
Q

how do you diagnose neurovirulent strains of equine herpes virus?

A

PCR (remember this!!!)

54
Q

what do the attenuated and inactivated vaccines for equine herpes virus 1 protect against

A

attenuated- resp signs, maybe shedding
inactivated- resp, abortion

55
Q

how does a protected/immune horse neutralize the virus? (this is a question)

A

neutralizing antibodies prevent virus from binding to epithelium

56
Q

what is the common name for equine infectious anemia (EIA)

A

swamp fever

57
Q

should we be worried about EIA in alberta?

A

YES - it is most common here

58
Q

who is susceptible to EIA? who is not?

A

All members of Equidae affected
* Clinical disease occurs in horses and ponies
* Donkeys may be without clinical signs

59
Q

how is EIA transmitted?

A

Mechanical transmission - Mouthparts of biting insects (Horse flies, stable flies, deer flies)

also:
fomites
in utero
milk
veneral
aerosols

60
Q

what drives the pathogenesis of EIA virus?

A

circulating immune complexes

61
Q

what are the clinical signs of EIA?

A

Fever, anemia and thrombocytopenia

Sudden onset acute phase (can cause death)
Chronic persistent infection
Recurrent clinical disease episodes
Asymptomatic (silent carrier)
Depression
Fever
Enlarged lymph nodes
Weakness
Weight loss
Anorexia
Edema
Nasal discharge
Mortality (50% of the diseased)

condense this *

62
Q

what does EIAV bind to?

A

erythrocytes

63
Q

what does EIA do to erythrocytes? (3 things)

A

Decrease erythrocyte life-span
Depressed erythropoiesis
Impaired flow of iron from macrophage to plasma

64
Q

what is significant about EIA and fevers?

A

causes recurrent febrile episodes - this also coinsides with thrombocytopenia

65
Q

how do we diagnose EIA? (know this) what are pros and cons? can we just do one test?

A

serology:
-agar gel immunodiffusion test, coggins test –> high false -ve)
-ELISA (higher rate of false +ve)
^ we must do both of these (KNOW THIS)

real time PCR (fails to detect carriers)

66
Q

is EIA reportable?

A

yes

67
Q

EIA is a retrovirus, therefore they are ____ carriers

what does this mean

A

lifelong

need to euthanize or quarantine for life

68
Q

how do we control EIA

A

Prevent transmission between horses –> fly control, single use needles, should not breed the positive ones since virus is transmitted via in utero, via milk, venereal routes. Also prevent aerosol transmission

69
Q

do we worry about west nile virus in north america?

A

YES

70
Q

who is the vector for west nile?

A

mosquitos and birds

71
Q

how does WNV get into brain?

A

axonal retrograde transport along peripheral neurons into the spinal cord or hematogenous transport across BBB

72
Q

what are the clinical signs of WNV

A

Stumbling, in-coordination, weak limbs, partial paralysis, muscle twitching and in some cases, death, sometimes fever

73
Q

vasculitis is seen with what viruses

A

equine herpes virus, WNV, EIA

74
Q

truth or false: WNV is primarily carried by erythrocytes

A

FALSE - leukocytes are the issue

75
Q

what viruses cause leukocyte associated viremia?

A

herpes, WNV

76
Q

what viruses cause neurological signs?

A

WNV, herpes, rabies, EEE, WEE, VEE

77
Q

what sample is needed to diagnose WNV?

A

serum

78
Q

how is WNV controlled?

A

minimize mosquito bites

79
Q

Equine herpesvirus (EHV)1 and 4 are different since

A

Seroprevalence of EHV1 is lower than that of EHV4

80
Q

A common outcome of equine herpesvirus (EHV)1 and West Nile virus (WNV) infection is

A

Infection of leukocytes

81
Q

What is the possible clinical sign of equine infectious anemia virus (EIAV) infection? Please mark the WRONG answer.

Recurring episodes of disease
Colic
Fever
Depression
Nasal discharge

A

Colic

82
Q

Viremia of EHV1

Follows lytic viral replication in trigeminal ganglion
Occurs after infection with neuropathogenic but not with non-neuropathogenic strains
Is mostly cell-associated
Is not involved in viral dissemination in the body
Is not evident in this infection

A

Is mostly cell-associated

83
Q

Anemia due to equine infectious anemia

(EIA) virus infection is
Due to increased erythrocyte life-span
Not related to compromised erythropoiesis
Due to destruction of erythroblasts
Non-immune mediated
Due to impaired flow of iron from macrophage to plasma

A

Due to impaired flow of iron from macrophage to plasma