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Year 4 Livestock and One Health > Small Ruminants: Skin and Ectoparasites > Flashcards

Small Ruminants: Skin and Ectoparasites Flashcards

1
Q
  1. What pathogen casues orf?
  2. How does orf present?
  3. What is the problem with orf?
  4. How is it spread?
A
  1. Parapox virus
  2. Vesicular/proliferative scabby lesions- mouth/head and teats (4-6 week duration)
  3. Painful- interferes with suckling, eating, predisposes to mastitis
  4. Spread by contact- damage to skin and mouth allows virus in- rough grazing
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2
Q
  1. How is orf controlled?
  2. What vaccine is available?
A
  1. Isolate clinical cases, disinfecting bottles, dosing guns etc
  2. Live- can cause disease (don’t use in unaffected farms), apply by scratching skin
    Do not use indoors- will contaminate housing
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3
Q

What three mites can affect sheep?

A

Psoroptes ovis
Chorioptes bovis
Trombicula (harvest mites)

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4
Q
  1. What mite causes sheep scab?
  2. How is it transmitted?
  3. How long does it take for extreme pruritis?
  4. What are the clinical signs?
A
  1. Psoropted ovis
  2. Direct contact or infected scab fomites- material on fencepost
  3. 6-8 weeks
  4. Kicking, scratching, rubbing, wool loss, ragged fleece, moist, yellow appearance
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5
Q

What can sheep scab potentially lead to in extreme cases?

A

Proggresively distressed
Stop eating causing severe weight loss and seizures

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6
Q

How is it diagnosed?

A
  • Choose itchiest sheep
  • Exudative lesion
  • Edge of lesion- wool pluck, skin scrape
  • Warm sample
  • Microscope

Pointed mouth parts and bell shaped sucker

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7
Q

What can be done if the skin scrapes are negative, but it is still believed to be scab?

A

Could be due to low numbers
* Sample again
* Send to veterinary lab agency
* ELISA- detects early stages

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8
Q

When is the ELISA sheep scab test useful?

A
  • Useful for an individual animal
  • Biosecurity/quarentine protocols
  • Whole flock testing- 12 sheep
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9
Q

Why is sheep scab very difficult to get rid of?

A

Survives off host for 17-19 days
Reinfection from environment easy

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10
Q

How is sheep scab treated?

A
  • Dexamethasone for severely affected sheep
  • OP- diazanon dip
  • ML:
    Ivermectin- 2 doses days apart, not sufficient, must move to clean
    Doramectin- 1 dose, must move
    Moxidetin 1%- 2 doses 10 days appart, don’t need to move
    Moxidectin 2%- single dose, don’t move

Withdrawal times vary

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11
Q

How can sheep scab be prevented?

A
  • Biosecurity
  • Observation not enough
  • Treat all bought in sheep- sheep grazing away
  • Double fencing
  • Cleansing, disinfection
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12
Q

What are common problems with sheep scab and treatments?

A
  • Diagnosis
  • Incorrect product
  • Underdosing
  • Injection technique
  • Poor dipping technique
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13
Q
  1. Where on the sheep does chorioptes bovis affect more commonly?
  2. What can it cause in rams?
  3. How is it treated?
A

1.
* Ventral abdomen
* Scrotum
2. Can cause infertility in rams due to increased blood flow from irritation therefore altering temperature of testes
3. OP dips

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14
Q

What parasite that affects sheep does this image show?

A

Bovicula ovis

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15
Q

What are the increased risks and decreased risks of lice infestation?

A

Increased:
* Housing- warm dark, dry

Decreased:
* Shearing reduces risk
* rainfall

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16
Q

How can lice be checked for?

A

Part fleece on:
* Back
* Flanks
* Hindlimbs
Look for clumps of red brown lice- 2-3mm long so visible

17
Q

How is lice in sheep treated?

A

Outdoors- shearing, rainfall, treat worst affected
Housed- synthetic pyrethroid pour ons, OP dip

18
Q

How can scrapie present?

A

Usually neurological but can present as primary skin disease

NOTIFIABLE

19
Q
  1. When is fly strike most common?
  2. What species of fly causes it and how?
A
  1. Common in may to october
  2. Lucillia sericata-
    Lay eggs in fleece
    larva hatch 12 hours later
    proteolytic enzymes and mouth hooks damage the skin
    Attracts other flies
20
Q
  1. What can fly strike potentially cause?
  2. What are the risk factors?
  3. How is it treated and controlled?
A
  1. Can develop toxaemia and die
  2. RF- temp, humidity >65%, faecal soiling, carcass on farm
  3. TX- early treatment, kill maggots (SP pour on, deltamethrin), clean wound, supportive Abs, NSAIDs, house
    Control- shearing, dagging, worm control, tail docking, lameness control, prophylactic insecticides

OP dip
Pyrethroid pour ons
IGRs 8-16 weeks

21
Q
  1. What is the name for the head fly?
  2. Where are head flys found?
  3. How are they controlled?
A
  1. Hydrotea irritans
  2. Horn base, ocular (discharge)
  3. Treat- OP dips, Pyrethroid pour ons, IGRs
22
Q

How long do the following treatments last against flies?
OP dips
Synthetic pyrethroid pour ons
IGRs

A
  • OP dips- 8-10 weeks
  • Synthetic pyrethroids pour ons- 8-16 weeks
  • Insect growth regulators- 8-16 weeks
23
Q

What is ovine sweet itch?

A

Uncommon
Hypersensitivity to midges

24
Q
  1. What is lumpy wool?
  2. What are the risk factors?
  3. What does it cause?
  4. How is it treated?
A
  1. Bacterial infection of dermatophilus congolensi
  2. Wet conditions after shearing, thin wooled breeds
  3. Crusty lesions with wool loss
  4. Penicillin 3-5 days
25
Q

What does the following image show?
How is it spread and treated?

A

Peri-orbital eczema- staphylococcus aureus

Spread by contact- feeding troughs
Treat with penicillin

26
Q
  1. What causes caseous lymphadenitis in sheep?
  2. Where does it affect?
  3. What does it cause?
  4. Why is there not effective treatment?
  5. How is it spread and diagnosed?
  6. How is it controlled?
A
  1. Corynebacterium pseudotuberculosis
  2. Affects external and internal lymph nodes- parotid
  3. Abscesses
  4. Antibiotics cannot penetrate abscesses
  5. Spread- close contact, fomites, resp. Diagnosis- culture, ELISA
  6. Test and cull, hyigene, vaccine available (not completely preventable)

Purchase isolate and test ELISA, hyigene of shearers, mobile dippers, handling

27
Q

What does this image show?
What causes it?

A

Ringworm
Trichophyton verrucosum

28
Q

What does the following image show?
What can cause this?

A

Photosensitisation
St Johns wort ingestion

29
Q

What not infectious causes can cause wool loss?

A

Thin or broken fibres
Natural shedding
Woolbreak- stress

30
Q

What are the two likely causes of abnormal fibres in sheep?

A

Border disease- pestivirus (hairy shakers)
Copper deficiency- growing lambs

31
Q
  1. In what conditions do ticks feed?
  2. Where are they typically found?
  3. Where else can they be found and why?
  4. What diseases can they act as a vector for?
A
  1. > 85% humidity, >7 degrees
  2. Traditionally upland and western UK
  3. Lowland farm microclimates- ditches, forests
  4. Tick born fever, tick pyemia, louping ill, q-fever (abortion), babesiosis (cattle), lyme disease
32
Q
  1. What causes tick borne fever?
  2. What does it cause in sheep?
A
  1. Anaplasma phagocytophilia
  2. Profound immuno-supression
    gateway infection
    Rams in autumn- spermatogenesis infertility
    Ewes in autumn- abortion

Do become immune

33
Q
  1. What causes tick pyemia?
  2. What does it cause in lambs?
A
  1. Mechanical transmission of staphylococcus aureus
  2. Polyarthritis/joint ill or spinal abscess

Immunosupression

34
Q
  1. What does looping ill cause pathologically?
  2. What are the clinical signs
  3. What is the morbidity?
  4. How can it be controlled?

Viral infection

A
  1. Non-supprative meningioencephomyelitis
  2. Varying severity from inco-ordination to seizures and death
  3. Morbidity- 5-60%
  4. Protective immunity in colostrum, vaccine, tick control, grazing
35
Q

How can tick control be done with animals?

A

Care with new born and naive
* Don’t expose to tick area for first time if pregnant
* pasturella pneumonia vaccine
* Looping ill vaccine

36
Q

What drugs can controll ticks?

A
  • Diazinon OP dip 3-6 weeks
  • SP pour ons- varies- 6-12 weeks

Year 4 Livestock and One Health (58 decks)

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