Sheep ectoparasites Flashcards

1
Q

What is another name for blowfly strike

A

cutaneous myiasis

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2
Q

When is the risk period for fly strike

A

between may and september

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3
Q

Describe the signs seen with blowfly strike

A

first sign is a patch of discoloured wool and agitation
pruritus
unpleasant smell

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4
Q

Describe the treatment of blowfly strike

A

application of insecticides (systhetic pyrethroids or organophophate dips)
shearing
cleaning of affected areas
topical antibiotics
NSAIDs

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5
Q

List some ways in which fly strike can be prevented

A

shearing/ dagging/ tail docking
reducing faecal soiling
organophophate dips, synthetic pyrethroids

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6
Q

What causes sheep scab

A

Psoroptes ovis
Is a mite

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7
Q

What is pediculosis

A

lice infestation

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8
Q

List 6 signs of pediculosis

A

can be asymptomatic
pruritus
excoriation
fleece damage and loss
severe infestations can result in anaemia
can look similar to scab

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9
Q

Describe how pediculosis be diagnosed

A

visual inspection
direct microscopy of hair samples

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10
Q

What are the treatment options for sheep lice

A

pour-on synthetic pyrethroid (deltamethrin or cypermethrin)
organo-phosphate dips

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11
Q

which sheep should be treated for sheep lice

A

all sheep in direct contact

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12
Q

When should sheep be preventatively treated for lice

A

the start of the winter housing period

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13
Q

Where do ticks spend the majority of their lifecycle

A

off the host

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14
Q

what is the most common tick of sheep

A

Ixodes rincus

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15
Q

what diseases can be spread to sheep by ticks

A

Louping ill
Tickbourne fever
Tick pyaemia

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16
Q

Describe louping ill

A

viral infection causing encephalomyelitis
is zoonotic

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17
Q

what are the symptoms of louping ill

A

seizures
paralysis
death

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18
Q

what sheep are most commonly affected by louping ill

A

weaned lambs
yearlings

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19
Q

describe how louping ill can be controlled

A

tick control
vaccination can play a role (but not currently avaliable)

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20
Q

What causes tickbourne fever

A

Anaplasma phagocytophilum

21
Q

What is tickbourne fever

A

immunosuppressive disease
bacteria infects and destroys WBC causing leucopaenia

22
Q

List 5 signs of tickbourne fever

A

pyrexia
anorexia
depression
pregnant ewes may abort
naive tups may become infertile

23
Q

What will happen if a naive animal is introduced to a TBF endemic area

A

more severe signs

24
Q

what is tick pyaemia

A

Staphylococcus infection of lambs often following
immunosuppression due to tickborne fever

25
When are lambs affected by tick pyaemia
2-12 weeks of age
26
what does tick pyaemia cause
abscesses develop throughout the body often in joints, tendons, muscle and brain
27
what signs may lambs with tick pyaemia display
severe lameness paralysis of backend death
28
List 3 host controls that can be carried out for ticks in sheep
avoid buying naive animals synthetic pyrethroids (deltamethrin and cypermethrin) organophosphate dips
29
what are the advantaes of synthetic pyrethroids
better operator safety longer protection
30
what is the disadvantage of synthetic pyrethroids
no immediate kill
31
what are the advantages of organophosphates
protect against more parasites immediate kill
32
what is a disadvantage of organophosphates
toxic to humans
33
List 3 ways ticks can be controlled in the environment
expose lambs to tick prone pastures in early spring when have some passive protection avoid tick prone pastures if possible drainage and scrub clearance of pasture
34
where is sheep scab notifiable
scotland
35
Is psoroptes ovis (sheep scab) viable off the host
yes- for 17 days
36
when is sheep scab prevalent
winter lots of contact
37
Describe how sheep scab can be diagnosed
skin scrabe blood coproantigen ELISA (early diagnosis)
38
Describe how sheep scab can be treated
organophosphate plunge dipping (diazinon) Macrocyclic lactone injections- moxidectin (1% or 2%), doramectin, ivermectin
39
What is the advantage of 2% moxidectin against sheep scab
last longer
40
what is a problem with 1% moxidectin against sheep scab
will react if sheep ever been given footvax
41
what is the problem with moxidectin
resistance
42
how long does moxidectin provide protection
28days residual protection
43
how long does doramectin provide protection
14 days residual protection
44
what residual protection does ivermectin have
no residual protection
45
what is the ivermectin protocol to treat sheep scab
two injections 7 days apart
46
List 5 challenges of sheep scab control
safety of chemical control measures resistance of mites to MLs Sub-clinical infestations biosecurity with neighbors and common grazing farmer motivation- under-reporting/ fatalistic view of scab control
47
Describe how sheep scab can be controlled
quarantine to avoid bringing in OP dipping is only consistently reliable way to prevent scab serology to dectect within 2 weeks of infestation
48
How can blowfly strike cause toxaemia and death
tocins released by damaged tissues and ammonia secreted by the maggots are absorbed through lesions into the sheep's bloodstream