Ectoparasitic Causes of Skin Disease Flashcards

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1
Q

Why are ectoparasites clinically important?

A

Directly impact welfare of host
Predispose to/cause other diseases in host
Vectors of disease
Clinical signs mimic other diseases
Act as pointers to other disease

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2
Q

How do ectoparasite affect welfare of host?

A

Cause pruritus
Cutaneous myiasis

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3
Q

What diseases do ectoparasites predispose host to?

A

Secondary bacterial infections
Anaemia

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4
Q

Examples of vectors of disease

A

Ticks
□ Babesiosis (cattle/dogs)
□ Louping ill (sheep/grouse)
□ Echinococcus (hydatidosis) (sheep)
Fleas
□ Dipylidium caninum (dog)
□ Bartonellosis (man)
□ Myxomatosis (rabbit)
Sandflies
□ Leishmaniasis

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5
Q

Which ectoparasites are of zoonotic importance?

A

Fleas
Sarcoptes
Cheyletiella

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6
Q

Which ectoparasites are of economic importance?

A

Psoroptes ovis - Sheep scap
Cause of significant loss
Notifiable disease in Scotland

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7
Q

Common clinical signs of skin surface parasite

A

Alopecia
+/- erosions
Crust
Scale
Secondary bacterial infection
Chronic changes

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8
Q

Which species do fleas affect?

A

Dog
Cat
Rabbit

Zoonotic!

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9
Q

Clinical signs of fleas

A

Pruritus
Specific lesion distribution

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10
Q

Lesion distribution in dogs

A

Caudal/dorsal part of body

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11
Q

Lesion Distribution in Cats

A

□ Head and neck pruritus
□ Symmetrical alopecia
□ Eosinophilic granuloma complex (EGC)
□ Miliary dermatitis

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12
Q

Lesion distribution in rabbits

A

Dorsal/rump - Ctenocephalides felis/canis
Pinnae - Spilopsyllis cuniculi

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13
Q

Which species do lice affect?

A

Farm animals
Horses
Guinea pigs
Birds

Small number may be present on clinically normal animals
Incidence greater when housed together

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14
Q

Surface mites of cattle

A

Chorioptes bovis - Common
Tailhead
Lower legs
Scrotum
Udder
Psoroptes - Rare

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15
Q

Surface mites of Sheep

A

Psoroptes ovis - Sheep scab
Chorioptes bovis - Scrotal mange

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16
Q

Surface mites of horses

A

Chorioptes equi (common)
Leg/tail mange, esp. horses with ‘feathers’
Psoroptes spp.
Body + ear mange
Neotrombicula sp. - harvest mite
Head/legs
Late summer/autumn

17
Q

Surface mites of dogs/cats

A

Otodectes - ear mite
Otitis – dark dry otic exudate
Cheyletiella - fur mite
Truncal scale
Zoonotic
Neotrombicula - harvest mite
Esp head/limbs, late summer/autumn

18
Q

Surface mites of rabbits

A

Cheyletiella - fur mite
Truncal scale +++
Zoonotic
Leporacus gibbus - fur mite
Often asymptomatic
Lesions – brown mite just visible
Psoroptes cuniculi - ear mite
Painful
Flakey adherent otic crust

19
Q

Clinical signs of burrowing mites

A

Pruritus
Alopecia
+/- papules
Hyperkeratosis
Crust

20
Q

Sarcoptes scabiei

A

Sarcoptic mange - Zoonotic
Very pruritic
Crust on pinnal margins/hocks/elbows

21
Q

Trixacarus

A

Burrowing mite of guinea bigs
Extremely pruritic - can cause seizures/death
Zoonotic

22
Q

Cnemidocoptes (Knemidocoptes)

A

Burrowing mite of birds
‘Scaly beak’
‘Scaly leg’

23
Q

Clinical signs of demodicosis

A

Causes by demodex - burrowing mite
Folliculitis
○ Pustules/papules/comedones/follicular casts
○ Alopecia
○ Inflammation/pruritis
○ +/- secondary lesions/infection
Furunculosis
○ Deep pyoderma

Associated with immunocompromised animals

24
Q

Which species does demodex affect?

A

Dog
Hamster
Occasionally cat

25
Q

Why are ticks of importance?

A

Vectors of may disease
Zoonotic
Heavy infestations can cause debilitation
Can lead to tick granuloma if mouthpieces not removed

26
Q

What is cutaneous myasis?

A

Blowfly strike - lays eggs in wound
Seen in sheep and rabbits
Severe welfare impact

27
Q

Which parasites are unlikely to be detected on host and why?

A

Multiple short periods on a variety of hosts
Most of life cycle is in environment
* Midges - Culicoides spp.
* Nuisance flies
* Dermanyssus gallinae

28
Q

What is sweet itch?

A

Hypersensitivity to culicoides spp. in horses
Causes pruritic lesions along crest, tail base and face

29
Q

What is Dermanyssus gallinae?

A

Red mite in chickens
Lives in environment
Only feed at night
Causes feather loss/irritation
Zoonotic

30
Q

Diagnostic methods for Fleas

A

Coat brushing onto paper

31
Q

Diagnostic methods for lice

A

Coat brushing onto paper/liquid paraffin
Unstained acetate tape strip
Hair pluck to look for eggs

32
Q

Diagnostic methods for surface mites

A

Unstained acetate tape strip
Superficial skin scrape
Coat brushing into liquid paraffin

33
Q

Diagnostic methods for deep mites

A

Deep skin scrape
Trichogram