Sheep ectoparasites

Question 1

What is another name for blowfly strike

Answer 1

cutaneous myiasis

Question 2

When is the risk period for fly strike

Answer 2

between may and september

Question 3

Describe the signs seen with blowfly strike

Answer 3

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

Question 4

Describe the treatment of blowfly strike

Answer 4

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

Question 5

List some ways in which fly strike can be prevented

Answer 5

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

Question 6

What causes sheep scab

Answer 6

Psoroptes ovis
Is a mite

Question 7

What is pediculosis

Answer 7

lice infestation

Question 8

List 6 signs of pediculosis

Answer 8

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

Question 9

Describe how pediculosis be diagnosed

Answer 9

visual inspection
direct microscopy of hair samples

Question 10

What are the treatment options for sheep lice

Answer 10

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

Question 11

which sheep should be treated for sheep lice

Answer 11

all sheep in direct contact

Question 12

When should sheep be preventatively treated for lice

Answer 12

the start of the winter housing period

Question 13

Where do ticks spend the majority of their lifecycle

Answer 13

off the host

Question 14

what is the most common tick of sheep

Answer 14

Ixodes rincus

Question 15

what diseases can be spread to sheep by ticks

Answer 15

Louping ill
Tickbourne fever
Tick pyaemia

Question 16

Describe louping ill

Answer 16

viral infection causing encephalomyelitis
is zoonotic

Question 17

what are the symptoms of louping ill

Answer 17

seizures
paralysis
death

Question 18

what sheep are most commonly affected by louping ill

Answer 18

weaned lambs
yearlings

Question 19

describe how louping ill can be controlled

Answer 19

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

Question 20

What causes tickbourne fever

Answer 20

Anaplasma phagocytophilum

Question 21

What is tickbourne fever

Answer 21

immunosuppressive disease
bacteria infects and destroys WBC causing leucopaenia

Question 22

List 5 signs of tickbourne fever

Answer 22

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

Question 23

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

Answer 23

more severe signs

Question 24

what is tick pyaemia

Answer 24

Staphylococcus infection of lambs often following
immunosuppression due to tickborne fever

Question 25

When are lambs affected by tick pyaemia

Answer 25

2-12 weeks of age

Question 26

what does tick pyaemia cause

Answer 26

abscesses develop throughout the body often in joints, tendons, muscle and brain

Question 27

what signs may lambs with tick pyaemia display

Answer 27

severe lameness
paralysis of backend
death

Question 28

List 3 host controls that can be carried out for ticks in sheep

Answer 28

avoid buying naive animals
synthetic pyrethroids (deltamethrin and cypermethrin)
organophosphate dips

Question 29

what are the advantaes of synthetic pyrethroids

Answer 29

better operator safety
longer protection

Question 30

what is the disadvantage of synthetic pyrethroids

Answer 30

no immediate kill

Question 31

what are the advantages of organophosphates

Answer 31

protect against more parasites
immediate kill

Question 32

what is a disadvantage of organophosphates

Answer 32

toxic to humans

Question 33

List 3 ways ticks can be controlled in the environment

Answer 33

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

Question 34

where is sheep scab notifiable

Answer 34

scotland

Question 35

Is psoroptes ovis (sheep scab) viable off the host

Answer 35

yes- for 17 days

Question 36

when is sheep scab prevalent

Answer 36

winter
lots of contact

Question 37

Describe how sheep scab can be diagnosed

Answer 37

skin scrabe
blood coproantigen ELISA (early diagnosis)

Question 38

Describe how sheep scab can be treated

Answer 38

organophosphate plunge dipping (diazinon)
Macrocyclic lactone injections- moxidectin (1% or 2%), doramectin, ivermectin

Question 39

What is the advantage of 2% moxidectin against sheep scab

Answer 39

last longer

Question 40

what is a problem with 1% moxidectin against sheep scab

Answer 40

will react if sheep ever been given footvax

Question 41

what is the problem with moxidectin

Answer 41

resistance

Question 42

how long does moxidectin provide protection

Answer 42

28days residual protection

Question 43

how long does doramectin provide protection

Answer 43

14 days residual protection

Question 44

what residual protection does ivermectin have

Answer 44

no residual protection

Question 45

what is the ivermectin protocol to treat sheep scab

Answer 45

two injections 7 days apart

Question 46

List 5 challenges of sheep scab control

Answer 46

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

Question 47

Describe how sheep scab can be controlled

Answer 47

quarantine to avoid bringing in
OP dipping is only consistently reliable way to prevent scab
serology to dectect within 2 weeks of infestation

Question 48

How can blowfly strike cause toxaemia and death

Answer 48

tocins released by damaged tissues and ammonia secreted by the maggots are absorbed through lesions into the sheep’s bloodstream