Ectoparasitic Causes of Skin Disease Flashcards
Why are ectoparasites clinically important?
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
How do ectoparasite affect welfare of host?
Cause pruritus
Cutaneous myiasis
What diseases do ectoparasites predispose host to?
Secondary bacterial infections
Anaemia
Examples of vectors of disease
Ticks
□ Babesiosis (cattle/dogs)
□ Louping ill (sheep/grouse)
□ Echinococcus (hydatidosis) (sheep)
Fleas
□ Dipylidium caninum (dog)
□ Bartonellosis (man)
□ Myxomatosis (rabbit)
Sandflies
□ Leishmaniasis
Which ectoparasites are of zoonotic importance?
Fleas
Sarcoptes
Cheyletiella
Which ectoparasites are of economic importance?
Psoroptes ovis - Sheep scap
Cause of significant loss
Notifiable disease in Scotland
Common clinical signs of skin surface parasite
Alopecia
+/- erosions
Crust
Scale
Secondary bacterial infection
Chronic changes
Which species do fleas affect?
Dog
Cat
Rabbit
Zoonotic!
Clinical signs of fleas
Pruritus
Specific lesion distribution
Lesion distribution in dogs
Caudal/dorsal part of body
Lesion Distribution in Cats
□ Head and neck pruritus
□ Symmetrical alopecia
□ Eosinophilic granuloma complex (EGC)
□ Miliary dermatitis
Lesion distribution in rabbits
Dorsal/rump - Ctenocephalides felis/canis
Pinnae - Spilopsyllis cuniculi
Which species do lice affect?
Farm animals
Horses
Guinea pigs
Birds
Small number may be present on clinically normal animals
Incidence greater when housed together
Surface mites of cattle
Chorioptes bovis - Common
Tailhead
Lower legs
Scrotum
Udder
Psoroptes - Rare
Surface mites of Sheep
Psoroptes ovis - Sheep scab
Chorioptes bovis - Scrotal mange
Surface mites of horses
Chorioptes equi (common)
Leg/tail mange, esp. horses with ‘feathers’
Psoroptes spp.
Body + ear mange
Neotrombicula sp. - harvest mite
Head/legs
Late summer/autumn
Surface mites of dogs/cats
Otodectes - ear mite
Otitis – dark dry otic exudate
Cheyletiella - fur mite
Truncal scale
Zoonotic
Neotrombicula - harvest mite
Esp head/limbs, late summer/autumn
Surface mites of rabbits
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
Clinical signs of burrowing mites
Pruritus
Alopecia
+/- papules
Hyperkeratosis
Crust
Sarcoptes scabiei
Sarcoptic mange - Zoonotic
Very pruritic
Crust on pinnal margins/hocks/elbows
Trixacarus
Burrowing mite of guinea bigs
Extremely pruritic - can cause seizures/death
Zoonotic
Cnemidocoptes (Knemidocoptes)
Burrowing mite of birds
‘Scaly beak’
‘Scaly leg’
Clinical signs of demodicosis
Causes by demodex - burrowing mite
Folliculitis
○ Pustules/papules/comedones/follicular casts
○ Alopecia
○ Inflammation/pruritis
○ +/- secondary lesions/infection
Furunculosis
○ Deep pyoderma
Associated with immunocompromised animals
Which species does demodex affect?
Dog
Hamster
Occasionally cat
