Sheep skin disease / Ectoparasites + tick borne disease

Question 1

What type of virus is orf / contagious pustular dermatitis?

Answer 1

Parapox virus

Question 2

How is orf spread?

Answer 2

• direct contact
• Damage to skin + mouth (e.g. thistles)
• Predispose mastitis in ewes

Question 3

How can you control orf?

Answer 3

• Isolate cases
• Disinfect bottles / drenching guns + buildings
• Vaccine

Question 4

Whats the problem with the orf vaccine?

Answer 4

• Live vaccine - if no history of orf can introduce into the flock
• Only vaccinate if on farm

Question 5

What are mites of sheep?

Answer 5

• Psoroptes ovis - sheep scab
• Chorioptes bovis
• Trombicula - harvest mite

Question 6

What are lice of sheep?

Answer 6

• Bovicola ovis

Question 7

What are ticks of sheep?

Answer 7

• Ixodes ricinus
• Haemaphyllis punctuata

Question 8

What are flies of sheep?

Answer 8

• Lucilia sericata
• Hydrotea irritans

Question 9

What are clinical signs of sheep scab?

Answer 9

• Loss of wool
• Nibble test
• Kicking, scratching, rubbing

Question 10

How is sheep scab diagnosed?

Answer 10

• Skin scrape of edge of lesion + microscope

Question 11

How do you treat scab?

Answer 11

• OP dip - diazanon

Question 12

How can you prevent sheep scab?

Answer 12

• Biosecurity
• Test / treat bought in animals
• Double fence neighbours
• Disinfect scanners + shearers

Question 13

Where is chorioptes bovis seen? What can it cause?

Answer 13

• Ventral abdomen, scrotum
• Causes pruritus / dermatitis + infertility due to inflammation of scrotum

Question 14

How is chorioptes diagnosed + treated?

Answer 14

• Dx = skin scrape
• Tx = OP dips

Question 15

When is lice more common?

Answer 15

• Winter
• Housing inside
• Longer coats

Question 16

How can you treat lice?

Answer 16

• Pyrethroid pour ons - Dysect / Crovect
• Plunge dip - OP

Question 17

What causes fly strike?

Answer 17

• Lucillia sericata

Question 18

What are risk factors of fly strike?

Answer 18

• Temperature
• Humidity
• Long fleece
• Wounds
• Lameness
• Faecal soiling

Question 19

How is fly strike treated?

Answer 19

• Clip + clean
• Kill maggots - crovect

Question 20

What is ovine sweet itch?

Answer 20

• Hypersensitivity to midges

Question 21

How does scrapie affect sheep?

Answer 21

• Usually neurological but can be primary skin disease = pruritus

Question 22

What can Staph aureus cause? How is it spread + treated?

Answer 22

• Peri-orbital eczema
• spread by contact, feeding troughs
• Tx = wound cleaning + 5 days of penicillin

Question 23

What causes lumpy wool?
Tx?

Answer 23

• Dermatophilus congolensis
• Tx = 5 days of penicillin

Question 24

What is cellulitis / sub cutaneous abscess a differential from?

Answer 24

• Caseous Lymphadenitis

Question 25

What causes CLA?
Tx?

Answer 25

• Corynebacterium pseudotuberculosis
• Affects lymph nodes + no effective treatment

Question 26

How is CLA diagnosed?

Answer 26

• Culture
• ELISA test

Question 27

How do you control CLA?

Answer 27

• Biosecurity - bought in animals
• Hygiene of shearers + dippers
• Test + cull affected animals

Question 28

What are other conditions affecting the skin?

Answer 28

• Ringworm
• Photosensitisation

Question 29

What can cause abnormal wool fibres?

Answer 29

• Border disease = hairy shakers
• Copper deficiency = poor wool quality

Question 30

What are different tick borne diseases?

Answer 30

• Tick borne fever
• Tick pyaemia - ‘cripples’
• Louping ill
• Q fever - coxiella burnetti
• Babesiosis
• Lyme’s disease

Question 31

What causes tick borne fever?
What are the clinical signs?

Answer 31

• Anaplasma phagocytophilia
• Immuno-suppression - predispose other disease
• Rams in autum = infertility
• Ewes in autum = abortion
• Do develop immunity

Question 32

What are clinical signs of tick pyaemia?

Answer 32

• Affect lambs - polyarthritis
• Joint-ill + immunosuppression

Question 33

What does louping ill cause?

Answer 33

• Non suppurative meningoencephomyelitis
• Incoordination
• Seizures + death