Pathological Diseases - Ectoparasites

Description: Most common type of parasite, Zoonotic, Macroscopic, Ctenocephalides felis = cat flea, Ctenocephalides canis = dog flea

Life cycle:

• Adult flea feeds on host, Flea lays eggs 20 eggs daily/ 300-500 lifetime
• Eggs hatch 2-14 days
• Larvae cuts out egg using chitin spike, feed on flea dirt
• Spin pupae (can survive 6-12 mnths)
• Emerge to warmth, vibration, CO2 (8-12 days)

Diagnosis:

• Seen or bitten
• Flea comb
• Wet paper test

Transmit: Myxamatosis, tapeworm, feline infectious anaemia, feline infectious enteritis, flea allergic dermatitis. Can cause anaemia in young animals.

• Spend entire life cycle on host
• Louse infestation = pediculosis
• Transmitted by close contact

Sucking Louse - Linognathus Setosus:

• Host = Dog
• Can cause anaemia

Biting Louse - Trichodectes Canis (dog)/ Felicola Subrostratus (cat)

• Chew on dead skin

• Blood sucking arachnid
• Not host specific
• Potential to transmit many diseases
• Infection may result in anaemia

Common Species:

• Sheep tick
• Hedgehog tick
• Brown dog tick
• Ornate dog tick

Myiasis - Infestation of live animals with the larvae of blue/ green bottle flies e.g fly strike. Hatch within 12 hours

Risk factors:

• Obesity
• Debilitation
• Urine Scalding
• D++
• Infected necrotic wounds

Types: Burrowing and Surface

Diagnosis: Skin scrapes, coat brushing, microscopy

Harvest mite - Neotrombicula Autumnalis:

• Larval stage = parasitic
  • Late summer/ autumn
  • Feed on birds/ mammals - serous tissue fluid
  • Drop into environment at nymph stage 
• Macroscopic as red dots
• Very pruritic

Ear mite - Otodected Cynotis

• Common in dogs, cats and ferrets (external ear canal)
• Diagnosis: visualise with otoscope, microscopy of swab 
• Clinical signs: discharge and otitis externa

Psoroptes Cuniculi (Rabbit)

• Clinical Signs: Crusting and scaling, very pruritic

Cheyletiella (Walking Dandruff)

• Suface mites cause exfoliative dermatitis
• Species:
  • C. Yasguri = dogs
  • C. Blakei = cats
  • C. Parasitovirax = rabbit
• Zoonotic
• Common in young/ immunosuppressed animals
• Will not reproduce on humans

Sarcoptes Sabii - Scabies/ Sarcoptic Mange

• Microscopic, subsurface burrowing mite
• Contageous and zoonotic
• Can live in environment for 2-3 days
• Common in dogs
• Clinical Signs: puritis, alopecia, scaling
• Diagnosis: Skin scrapes, microscopy and serology

Notoedres Cati - Feline Scabies

• Rare in UK
• Clinical Signs: puritis, alopecia and crusting

Demodex

• Microscopic, follicular (lives in hair follicles), subsurface mite
• Non Puretic
• ***** to Puppies 2-3 days

Pustular Demodicosis:

• Swollen skin with pustules
• Pachydermatitis (thickening) of the skin

Squamous Demodicosis:

• Desquamation (shedding of outer layers of skin)
• Alopecia
• Cyanosis