Ectoparasites

Question 1

Lice in cattle

Answer 1

Bovicola bovis - most common, chewing, usually on the head
Linognathus vituli - sucking, around the head
Haematopinus eurysternus - sucking, around the horns

Question 2

Treatment of lice in cattle

Answer 2

Pour-on synthetic pyrethroid - deltamethrin (kills everything)
Pour-on group 3 ML - ivermectin, doramectin, eprinomectin (kills everything)
Injectable group 3 ML - ivermectin, doramectin, eprinomectin (removes sucking and >98% biting)

Question 3

Infectious Bovine Keratoconjuntivitis - agent, vectory, signs

Answer 3

Moraxella bovis bacterium
Face fly
Corneal ulcers, oedema, lacrimation, opacity, epiphora

Question 4

4 stages of Infectious Bovine Keratoconjunctivitis

Answer 4

1 - tearing, lacrimation, photophobia, small central corneal ulcer
2 - ulcer spreads across cornea, cloudy cornea, neovascularisation, pink cornea
3 - ulcer spreads, inner eye fills with fibrin and WBCs, eye looks yellow/brown
4 - ulcer covers entire cornea, iris adhesions

Question 5

Treatment of Infectious Bovine Keratoconjunctivits

Answer 5

Antibiotics - IM, SC, topical, subconjunctival
NSAIDS
Prevention - fly control with synthetic pyrethroids (eg. cypermethrin), biological control (friendly flies/parasitic wasps)

Question 6

Mites

Answer 6

Surface feeders - Chorioptes spp., Psoroptes spp.
Burrowing - Sarcoptes spp., Demodex spp.

Question 7

Ticks in livestock

Answer 7

Ixodes ricinus
Haemaphysalis punctate

Question 8

Diagnosis of tick infestations

Answer 8

History
Examination of skin
Examination of skin scarping/sticky tape impressions (ticks or eggs)

Question 9

Control of ticks

Answer 9

Host control
- no licenced pour-on SP or MLs
Environmental
- avoid tick prone pasture
- improve pasture to decrease tick populations
- cannot use acaricide

Question 10

Aetiology of photosensitisation in cattle

Answer 10

Direct photosensitisation occurs when a chemical comes from a defect in the animals metabolism of its RBCs, or plant such as St Johns wort
Secondary photosensitisation occurs in animals with liver damage which interferes with the complete breakdown of chlorophyll, leading to accumulation of a photosensitive chemical
Local photosensitivity can result as a reaction to the sap of some plants

Question 11

Clinical signs and diagnosis of Photosensitisation in cattle

Answer 11

Non-pigmented skin is affected
Hair loss, reddening, peeling
Ulceration of skin
Crusting, bleeding
Diagnosis based on clinical signs

Question 12

Treatment and prevention of photosensitisation in cattle

Answer 12

Move to cool, shaded housing
Fly control
Supportive treatment
Treatment of liver failure (if present)
Do not breed from affected animals
Identify and remove possible plant sources

Question 13

Lice infestation (pediculosis) in sheep

Answer 13

Biting - Damalina (Bovicola) spp.
Sucking - Haematopinus spp., Linognathus spp.

Question 14

Clinical signs of pediculosis in sheep

Answer 14

Asymptomatic
Pruritis
Excoriation
Fleeces damage/loss
Severe infestations can cause anaemia
Can look similar to scab

Question 15

Diagnosis of pediculosis in sheep

Answer 15

Visual inspection
Direct microscopy of hair samples

Question 16

Treatment of lice in sheep

Answer 16

Pour-on synthetic pyrethroid - deltamethrin, cypermethrin (kills biting lice)
Organophosphate dips (kills everything)
Treat all animals in direct contact

Question 17

Diseases spread by ticks

Answer 17

Louping ill
Tickborne fever
Tick pyaemia (sheep only)

Question 18

Control of ticks

Answer 18

Host control
- avoid buying naive animals
- synthetic pyrethroids - deltamethrin, cypermethrin
- OP dips - care with application, immediate kill
Environmental control
- expose lambs while they have passive protection
- avoid tick prone pastures
- decrease tick population

Question 19

Sheep scab

Answer 19

Psopties ovis

Question 20

How long is sheep scab viable off the host and how long is the prepatent period?

Answer 20

17d off host
PP 14d

Question 21

Diagnosis of sheep scab

Answer 21

Skin scrape - from edge of lesions, funnel shaped suckers
Blood coproantigen ELISA - early diagnosis and deciding on which animals to treat

Question 22

Treatment of sheep scab

Answer 22

OP dip - diazinon
Group 3 ML injection - moxidectin, doramectin, ivermectin

Question 23

How many days of protection do the group 3 MLs have on scab treatment?

Answer 23

Moxidectin - 28d
Doramectin - 14d
Ivermectin - 0d

Question 24

What are the challenges with controlling sheep scab?

Answer 24

Safety of chemical control measures
Resistance of mites to MLs and increased exposure to GI parasites
Cannot use 2% formulations of moxidectin in animals that have had footvax vaccine as it will kill them
Sub-clincial scab infestations
Biosecurity
Farmer motivation - social stigma leads to under-reporting

Question 25

Control of sheep scab

Answer 25

Quarantine - min 2wks
OP dips
Serology - blood test with high sensitivity and specificity gives ability to detect scab withing 2wks of infestation