Scabies & Other Parasitic Skin Disease (Marsella)

Question 1

Canine scabies

Answer 1

• Sarcoptes scabei canis
• Not host specific (zoonotic)
• Contagious

Question 2

Sarcoptes mite

Answer 2

• Male mite on skin surface
• Female burrows into stratum corneum
• Egg → larvae (6 legs) → nymphs (6 legs) → adults (8 legs)
• Life cycle 3 wks

Question 3

Sarcoptes transmission

Answer 3

Direct contact. Does not survive long in the environment (48 hrs).

Question 4

Sarcoptes zoonosis

Answer 4

• 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

Question 5

Rapidity and severity of lesions and pruritis of canine scabies depends on

Answer 5

• previous exposure
• # of mites

Question 6

Pathogenesis of canine scabies pruritis

Answer 6

• hypersensitivity
• mechanical irritation
• pruritogenic substances from saliva & species

Question 7

Canine scabies clinical features

Answer 7

• Intense pruritis
  
  • Ventral abdomen, pinnae, hocks, elbows
• Papules
• Excoriations, crusts, alopecia
• 2º infections
• Chronic dz
  
  • hyperpigmentation
  • lymphadenopathy
  • wt loss
  • hyperglobulinemia

Question 8

Norwegian scabies

Answer 8

• Rare
• Thick crusts
• Numerous mites
• Little pruritis
  
  • Immunosuppressed
  • Steroids
  • Puppies

Question 9

Scabies incognito

Answer 9

• Well groomed animals
• Intense pruritis
• No lesions

Question 10

Canine scabies diagnostics

Answer 10

• Clinical signs
• Superficial skin scrape (w/ KOH)
  
  • Margins of pinnae, elbows, hocks
• Response to treatment

Question 11

Canine scabies therapy

Answer 11

• 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

Question 12

Feline scabies

Answer 12

• Notoedric mange
• Rare
• Zoonotic
• Life cycle 21 days

Question 13

Feline scabies clinical signs

Answer 13

• Extreme pruritis
• Erythema, crusting papules
• Distrubution
  
  • Head & neck
  • generalized

Question 14

Feline scabies diagnosis

Answer 14

• Clinical signs
• Superficial skin scrape
• Response to treatment

Question 15

Feline scabies therapy

Answer 15

• LymDip
• Revolution
• Ivermectin
• Treat all animals in contact
• Extend treatment beyond duration of life cycle

Question 16

Cheyletiella

Answer 16

• “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

Question 17

Cheyletiella pathogenesis

Answer 17

Digesting enzyme secretion (eat dissolved skin) → skin irritation → scratching, hairloss, scabs, wounds

Question 18

Cheyletiella zoonosis

Answer 18

• Transient zoonosis
  
  • Unable to reproduce on human skin
• Papular eruptions & pruritis
• Self limiting once source of infection has been removed

Question 19

Cheyletiella life cycle

Answer 19

• Completed in 3 wks
• Eggs → larvae (6 legs) → nymphs (8 legs) → adults (8 legs)

Question 20

Cheyletiella clinical signs in dogs

Answer 20

• Puppies
• Scaling and pruritis
• Dorsal distribution

Question 21

Cheyletiella clinical signs in cats

Answer 21

• Miliary dermatitis
• Mild-mod pruritis
• Asymptomatic carriers

Question 22

Cheyletiella clinical signs in rabbits

Answer 22

• Scaling
• Scapular area often affected
• No primary lesions

Question 23

Cheyletiella diagnosis

Answer 23

• Demonstration of eggs or mites
  
  • Combing technique
  • Superficial skin scrape
  • tape impression

Question 24

Cheyletiella therapy

Answer 24

• Pyrethrin
• Lime sulfur dips
• Ivermectin
• Fipronil (NOT IN RABBITS)
• Selamectin
• Clean environment

Question 25

Pediculosis in dogs caused by

Answer 25

• Trichodectes canis (biting lice)
• Linognatus setosus (sucking lice)

Question 26

Pediculosis

Answer 26

• Host specifc (not zoonotic)
• Spends entire life cycle on host
  
  • limited survivial in environment
• Life cycle 3 wks
• Spreads via direct contact

Question 27

Pediculosis cinical signs

Answer 27

• Esp. in winter months
• Range from asymptomatic to intense pruritis
• Few direct lesions
• 2º excoriations
• Seborrhea
• Anemia
• Matted coat w/ nits (eggs)

Question 28

Pediculosis diagnosis

Answer 28

• ID of lice & eggs
  
  • Brush
  • Acetate tape impression
  • Magnifying lens

Question 29

Pediculosis therapy

Answer 29

• Clip coat in long-haired animals
• Treat to cover life cycle
• Pyrethrins
• Fipronil
• Lime sulfur dips