Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Module 20: Global Vet Med > Rabies & Other Neurological Diseases of Equids > Flashcards

Rabies & Other Neurological Diseases of Equids Flashcards

1
Q

what are equine notifiable diseases (7)

A

rabies

equine infectious anemia

dourine

west nile virus

african horse sickness

equine viral arteritis

glanders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are non notifiable diseases of importance (3)

A

equine influenza

piroplasmosis

equine protozoal myeloencephalitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are diseases of zoonotic potential

A

rabies

WNV

glanders

hendra virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what diesease can have a quiescent carrier stage (3)

A

equine infectious anemia

piroplasmosis

equine viral arteritis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what viruses cause myeloencephalitis or encephalitis (5)

A

equine herpes virus myeloencephalopathy (EHM)

rabies

arboviruses (WNV, JE, WEE, EEE, VEE)

borna virus

hendra virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what do arboviruses have in common (3)

A

most OIE list B diseases

most spread between mosquitos and birds

most are SERIOUS zoonosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the mentation clinical signs of viral encephalitides

A

many infections are subclinical – except rabies

mentation: hyperexcitibility or lethargy (profound), comatose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the behavioural clinical signs of viral encephalitides (3)

A

head pressing, self-mutation, compulsive walking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the gait derangements of viral encephalitides

A

ataxia, paresis and paralysis, muscle fasciculations in WNV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are cerebral and brainstem signs of viral encephalitides

A

other cerebral/brainstem signs: circling, blindness, deafness

recumbency

fever

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the epidemiology of equine rabies infection

A

skunks, racoons, red fox most common in US

dogs cats and other horses can spread

small carnivoces (opossum, pole cat) and bats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the etiopathogenesis of equine rabies infection

A

virus multiplies in myocytes at bite site and infects peripheral nerves via nerve endings/NMJs

progresses along PN via axoplasmic flow to spinal and dorsal root ganglia

rapid multiplication in CNS (brain, spinal cord, sympathetic trunk) spread in CSF and blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the rabies virus

A

neutropic rhabdovirus (lyssavirus, rhabdoviridae)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the pathogenesis of equine rabies infection (4)

A
  1. no spread within blood or lymph fluid
  2. multiplies neurones, perikaryons of neurons
  3. accumulation of nucleocapsid, negri body formation
  4. increase in cellularity in CSF once reaches – may then be detectable by PCR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the incubation period of rabies

A

9 days to 1 year

depends on bite site

direct entry of virus to neural tissue allows short IP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the clinical signs of rabies

A

very variable in the horse

must be considered DDX for all neurological cases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the early signs of rabies

A

hyperasthesia (an increase in the sensitivity of any of your senses)

ataxia

behaviour change

anorexia

paresis

colic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the later signs of rabies infection

A

cerebral signs with rapid progression and deterioration ususal over 48 h

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the furious form signs in rabies

A

aggression

self mutilation

photophobia

hyperasthesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are further clinical progression signs of rabies infection

A

progression to recumbency

often with multiple buckling attempts to stand

aggression may remain present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

how is rabies infection diagnosed (4)

A
  1. clinical signs (self mutilation)
  2. immunofluorescent antibody test on fresh brain tissue
  3. histopathology (non-suppurative encephalomyelitis)
  4. negri bodies pathognomonic for rabies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what considerations need to be made when diagnosing rabies

A

full protective equiment when handling any tissue

contact OV lab to move carcass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the treatment of rabies

A

fatal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how is rabies prevented

A

vaccination in high risk areas

inactivated vaccine IM in high risk regions

stray dog control

do NOT vaccinate horses that have had immediate contact with suspected case – monitor for incubation period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what does EHV1 cause

A

equine herpes virus 1 myeloencephalopathy

resp disease in young horses, abortion storms, chorioretinopathy, myeloencephalopthy (EHM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what is the shedding period post infection of EHV1

A

1-3 weeks

80% ALL horses latently infected – recrudescence and further shedding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is the rarest manifestation of EHV1 and what are the signs of this manifestation

A

Equine Herpes Myeloencephalopathy (EHM)

pyrexia and resp signs (rhinopneumonitis) in herd mates or individuals with neuro signs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the neurotropic strain of EHV1

A

single AA polymorphism in DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what does the neurotropic strain of EHV1 cause

A

causes resp spread –> basement memb –> lymph nodes –> leukocyes –> vascular endothelium (9-13d post infection)

causes immune mediated vasculitis

ischemic myeloencephalopathy

outbreaks of ataxia and urinary incontinence in mature horses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

is the horse protected by prev vaccination against neurotropic strain of EHV1

A

not protected by prev vaccination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what are the signs of EHV1 myeloencephalopathy

A

URT signs

pyrexia

inappetance

lethargy

symmetric hindlimb ataxia and paresis

urinary/fecal retention

recumbency

CN signs (esp CN V, VII, VIII, XII)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what are more rare signs of EHV1 myeloencephalopathy

A

uveitis

hypopyon

retinal detachment

blindness

occasional lower limb edema

33
Q

what signs usually stabilize in EHV1 myeloencephalopathy

A

neurological signs usually stabilize within 24-48hours but variable pathogenicity in different strains

34
Q

what is chorioretinitis

A

common post infection with EHV1

bullet hole lesions in the chrioretina

35
Q

what would clinical signs of a EHV1 myeloencephalopathy look like

A

clinical signs occur in up to 40% in herd

may be preceeded by second pyrexia bout

edema of limbs, perineum

hind limb ataxia

urinary overflow incontinence

atonic tail

sensory deficits

mares develop neuro signs may abort in last trimester with isolation of same viral strain

may involve forebrain: dull mentation, low head carriage, inability to rise, may be central vision loss

36
Q

how is EHV1 myeloencephalopathy diagnosed (8)

A
  1. history
  2. clinical signs
  3. evidence in herd members of pyrexia/URT or neuro disease
  4. multicentric lesions affecting cauda equina but CN deficits also cna be present
  5. CSF: xanthochromia (bilirubin in CSF), PCR
  6. serology: CFT for IgM or paired ELISA
  7. viral isolation: PCR, culture of nasopharyngeal swab or blood
  8. necropsy
37
Q

how is EHM treated

A
  1. anti-inflammatories:

NSAIDs: phenylbutazone may decrease endothelial inflammation

corticosteroids: controversial but useful for 2-3 days
2. supportive:

position/slings

antimicrobials

urinary catherization/rectal evacuation

hydration & nutrition

  1. antiviral?

acyclovir poor bioavailability

valacyclovir better ($$)

  1. quarantine and hygiene measures

shed for up to 3 weeks after cessation of c/s

38
Q

how long does shedding occur after cessation of clinical signs of EHM

A

shed for up to 3 weeks after cessation of c/s

39
Q

how is EHV1 myeloencephaopathy prevented

A

difficult

neuro cases may still be infectious – effective isolation needed

vaccination? does not prevent EHM but will increase herd immunity and decrease shedding period if exposed to EHV1

herd management: keep youngstock and older broodmares in separate areas

consider vaccination of all stock – may decrease incidence of abortion

40
Q

what is the prognosis of EHV1 myeloencephaopathy

A

related to disease severity and response to treatment

recumbent – poor/grave

less severe –> complete recovery or residual deficits

41
Q

what type of virus is WNV

A

flavivirus

42
Q

what are the hosts of WNV

A

birds

humans

horses

other mammals

43
Q

what are the most important host in WNV

A

birds

dead birds act as a screen

humans and horses are dead end hosts

44
Q

what is the zoonotic disease of WNV

A

encephalitis, myositis, neuralgia

45
Q

what are the vectors of WNV

A

mosquitos

maybe ticks

46
Q

where is WNV endemic

A

africa

southern europe

asia

middle east

47
Q

what are the clinical signs of WNV

A

ataxia, paresis

muscle fasiculations

hyperasthesia

behavioural changes

CN deficits: VII, XII, IX

combo of peripheral and central signs suggestive

48
Q

what is the mortality rate of WNV

A

30-40%

49
Q

how is WNV diagnosed (5)

A
  1. clinical signs
    - combo of neurological signs

+/- fever, muscle fasiculations

  1. IgM ELISA 2 weeks
  2. IgG species specific ELISA
  3. PCR on EDTA blood or brain tissue
  4. brain immunohistochemistry
50
Q

how is WNV prevented

A
  1. vector control
  2. vaccination
51
Q

how is WNV controlled through vectrol control (6)

A
  1. reduce mosquito breeding sites
  2. vector proof meshes on stables
  3. mosquito repellent
  4. fans/dispersal devices
  5. treat still water sources
  6. surveillence schemes to check for parasite in dead birds
  7. APHA monitoring of suspect cases
52
Q

how is WNV controlled through vaccination

A

primary course: 2 doses at interval of 4 weeks; then anual booster

53
Q

what type of virus is eastern/western/venezuelan encephalitis virus

A

alpha virus

54
Q

where is eastern/western/venezuelan encephalitis virus endemic to

A

americas

55
Q

is eastern/western/venezuelan encephalitis virus zoonotic

A

yes

56
Q

what is the fatality rate of eastern/western/venezuelan encephalitis virus

A

EEE: 75-90%

VEE: 40-80%

WEE: 19-50%

57
Q

what are the reservoirs and vectors of eastern/western/venezuelan encephalitis virus

A

reservoirs: birds/small mammals
vector: mosquits

58
Q

which one of the eastern/western/venezuelan encephalitis virus causes a viremia such that the horse becomes the primary reservoir

A

VEE

59
Q

what are the clinical signs of eastern/western/venezuelan encephalitis virus

A

wide range: asymptomatic to severe CNS signs

initial viremia –> fever, lethargy, stiffness

behavioural changes

blindness, cranial nerve deficits

ataxia, paresis

recumbency, seizures, coma

60
Q

how is eastern/western/venezuelan encephalitis virus prevented

A

100% preventable through proper vaccination

horses that reside in endemic areas and <4 years old should get alphavirus vaccines 3x per year

combined vaccination protocols

61
Q

is eastern/western/venezuelan encephalitis virus notifiable

A

yes

62
Q

how is eastern/western/venezuelan encephalitis virus diagnosed

A

clinical signs and epidemiology suggestive

virus detection/isolation

serology

63
Q

where is the hendra virus

A

aus

64
Q

what are the risk factors for hendra virus (6)

A
  1. food trees
  2. bat birthing season
  3. TBs
  4. >8yo
  5. pasture housing
  6. pregnancy
65
Q

what is the reservoir of hendra virus

A

fruit bats

66
Q

what are the clincal signs of hendra virus

A

pyrexia

severe pneumonia

frothy nasal discharge

icterus

recumbency

death

67
Q

how is hendra virus diagnosed

A

signs

virus isolation

serology

PCR

histopathology/EM

68
Q

is hendra virus zoonotic

A

yes

careful with PM

69
Q

where is the borna virus located

A

germany

austria

switzerland

70
Q

what type of virus is borna virus

A

neurotropic

spread to and throughout nervous system

71
Q

what does borna virus cause

A

immunological response induces disease

meningoencephalitis/encephalitis

72
Q

what is borna virus associated with in people

A

psychological disease

73
Q

what are the clinical signs of borna virus

A

mentation and behavioural changes

ataxia, paresis

cranial nerve dysfunction

decreased sensation

74
Q

how is borna virus diagnosed

A

history, clinical signs

CSF

serology

PM – histopathology, virology, PCR, immunohistochemistry

75
Q

what are the disease outcomes of borna virus

A
76
Q

what is the general treatment of viral encephalitides

A

no specific treatment – anti-viral meds? some known benefit for EHV1/EHM

supportive

  • antiinflammatories

nursing

fluids and nutritional support

sligns for recumbent horse

77
Q

what are the safety percautions for clinical cases

A

cover cuts with water resistant dressing

PPE

hand cleansers/soap

disinfectants

waste disposal bags

P2 particulate respirators

78
Q

how is infection prevention

A
  1. reduce exposure to vectors (mosquitos, stable management)
  2. vaccination: WNV, EEE/WEE/VEE
79
Q

how is the UK industry protected

A

vet vigilance for unusual field clinical case key –> prompt reporting and isolation (dourine, EIA, WNV and AHSV)

care with imported horses (10 day health certificate)

vigilance for incorrect/absent passports

vaccination for at risk horses (WNV)

updating and attention to disease outbreak status

continued monitoring (senitenel birds, culicoides species, tick populations)

Module 20: Global Vet Med (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions