Scabies & Other Parasitic Skin Disease (Marsella) Flashcards
Canine scabies
- Sarcoptes scabei canis
- Not host specific (zoonotic)
- Contagious
Sarcoptes mite
- Male mite on skin surface
- Female burrows into stratum corneum
- Egg → larvae (6 legs) → nymphs (6 legs) → adults (8 legs)
- Life cycle 3 wks
Sarcoptes transmission
Direct contact. Does not survive long in the environment (48 hrs).
Sarcoptes zoonosis
- Rxn with in 24 hrs
- Pruritic papules
- S. scabei canis does NOT reproduce on human skin
- Lesions resolves within 12-14 days, if no further contact w/ affected dogs
Rapidity and severity of lesions and pruritis of canine scabies depends on
- previous exposure
- # of mites
Pathogenesis of canine scabies pruritis
- hypersensitivity
- mechanical irritation
- pruritogenic substances from saliva & species
Canine scabies clinical features
-
Intense pruritis
- Ventral abdomen, pinnae, hocks, elbows
- Papules
- Excoriations, crusts, alopecia
- 2º infections
- Chronic dz
- hyperpigmentation
- lymphadenopathy
- wt loss
- hyperglobulinemia
Norwegian scabies
- Rare
- Thick crusts
- Numerous mites
-
Little pruritis
- Immunosuppressed
- Steroids
- Puppies
Scabies incognito
- Well groomed animals
- Intense pruritis
- No lesions
Canine scabies diagnostics
- Clinical signs
- Superficial skin scrape (w/ KOH)
- Margins of pinnae, elbows, hocks
- Response to treatment
Canine scabies therapy
- Topical
- Lime sulfur dip (LymDip)
- Selamectin (Revolution)
- Fipronil (Frontline)
- Systemic
- Ivermectin (Ivomex, Heartgard)
- Milbemycin (Interceptor)
- Treat all animals in contact
- Pruritis may persist for short time after treatment
Feline scabies
- Notoedric mange
- Rare
- Zoonotic
- Life cycle 21 days
Feline scabies clinical signs
- Extreme pruritis
- Erythema, crusting papules
- Distrubution
- Head & neck
- generalized
Feline scabies diagnosis
- Clinical signs
- Superficial skin scrape
- Response to treatment
Feline scabies therapy
- LymDip
- Revolution
- Ivermectin
- Treat all animals in contact
- Extend treatment beyond duration of life cycle
Cheyletiella
- “Walking dandruff”
- Large, obligate parasite w/ hooklike mouthparts
- Spends entire life on host but can survive in environment for 10 days
- C. yasguri (dogs), C. parasitovorax (rabbits), C. blakei (cats)
- Zoonotic
Cheyletiella pathogenesis
Digesting enzyme secretion (eat dissolved skin) → skin irritation → scratching, hairloss, scabs, wounds
Cheyletiella zoonosis
- Transient zoonosis
- Unable to reproduce on human skin
- Papular eruptions & pruritis
- Self limiting once source of infection has been removed
Cheyletiella life cycle
- Completed in 3 wks
- Eggs → larvae (6 legs) → nymphs (8 legs) → adults (8 legs)
Cheyletiella clinical signs in dogs
- Puppies
- Scaling and pruritis
- Dorsal distribution
Cheyletiella clinical signs in cats
- Miliary dermatitis
- Mild-mod pruritis
- Asymptomatic carriers
Cheyletiella clinical signs in rabbits
- Scaling
- Scapular area often affected
- No primary lesions
Cheyletiella diagnosis
- Demonstration of eggs or mites
- Combing technique
- Superficial skin scrape
- tape impression
Cheyletiella therapy
- Pyrethrin
- Lime sulfur dips
- Ivermectin
- Fipronil (NOT IN RABBITS)
- Selamectin
- Clean environment
Pediculosis in dogs caused by
- Trichodectes canis (biting lice)
- Linognatus setosus (sucking lice)
Pediculosis
- Host specifc (not zoonotic)
- Spends entire life cycle on host
- limited survivial in environment
- Life cycle 3 wks
- Spreads via direct contact
Pediculosis cinical signs
- Esp. in winter months
- Range from asymptomatic to intense pruritis
- Few direct lesions
- 2º excoriations
- Seborrhea
- Anemia
- Matted coat w/ nits (eggs)
Pediculosis diagnosis
- ID of lice & eggs
- Brush
- Acetate tape impression
- Magnifying lens
Pediculosis therapy
- Clip coat in long-haired animals
- Treat to cover life cycle
- Pyrethrins
- Fipronil
- Lime sulfur dips
