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PARASITOLOGY - 1 > 9 – Mites > Flashcards

9 – Mites Flashcards

1
Q

Arachnida 3 main groups

A
  • Burrowing mites: short legs
  • Surface mites longer legs
  • Ticks
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2
Q

General life cycle of mites

A
  • Adults (8 legs) on host
  • Eggs on host
    o Resistant to some treatment
  • Larvae (6 legs) on host
  • Nymphs (8 legs) on host
  • *10-21 days
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3
Q

Pathogenesis of mite acariasis

A
  • Range from no effects to severe dermatitis (mange)
  • Hypersensitivity
  • Excoriation and secondary bacterial infection
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4
Q

Burrowing mites

A
  • Dorso-ventrally flattened
  • Short legs
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5
Q
A
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6
Q

Burrowing mites: examples

A
  • Sarcoptes sp. (canine scabies mite)
  • Notoedres sp. (feline scabies mite)
  • Demodex sp. (demodectic mange mite)
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7
Q

Sarcoptes scabei: dogs

A
  • Highly contagious with other dogs, wild canids
  • Transiently zoonotic (self resolving)
  • *high scratching
  • *EVERYWHERE
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8
Q

Sarcoptes adults

A
  • Short legs
  • Long unjointed pedicles
  • Survive in cool, humid environments for up to 3 weeks
  • Many ‘spikes’ to burrow in the skin
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9
Q

Sarcoptic mange

A
  • Hairless areas (ears, elbows, ventrum, tarsal)
  • INTENSE pruritus (hypersensitivity)
  • Erythema
  • Crusts
  • Hair loss, excoriation
  • Hyperkeratosis
  • +/- mites (depends where you take a skin scrape from)
    o Ex. ear: wont find them
    o Go along edges!
  • *TREAT IT REGARDLESS!
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10
Q

Human skin lesions associated with zoonotic Sarcoptes

A
  • Some red marks
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11
Q

Notoedres sp.: cats

A
  • Highly contagious among cats
  • Transient zoonoses
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12
Q

Notoedres cati: adults

A
  • Smaller than Sarcoptes
  • Do NOT survive in environment
  • *would look at the species it came from!
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13
Q

Notoedres sp. : feline scabies

A
  • Ears
  • Face and eyelids (+/- feet and perineum)
  • Intense pruritus
  • Dry, crusty skin
  • Hair loss, excoriation
  • Hyperkeratosis
  • Lymphadenopathy
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14
Q

Demodex spp.

A
  • Not zoonotic, not contagious
    o Except D. gatoi
  • No environmental survival
  • ‘vertical’ transmission: close contact with dam
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15
Q

Demodex spp. adults

A
  • Live in hair follicles and sebaceous glands (squeeze!)
  • Eight legs on throax
  • Clinical significance: number of adults AND larvae&nymph:adult ratio
  • *’long cigar’
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16
Q

Demodectic mange in dogs: clinical presentations

A
  • Most asymptomatic (normal fauna)
  • Localized demodicosis
  • Generalized demodicosis
  • Pododemodecosis
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17
Q

Localized demodicosis

A
  • Young (3-18months)
  • Mouth, ears, forelegs, rarely ear canals
  • Focal alopecia
  • Squamous
  • Silver scaling
  • Not pruritic
  • Self-resolving: most self-cure within 1-2 months
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18
Q

Generalized demodicosis

A
  • Any age, prognosis better for young
  • Starts face and limbs
  • *when 5 or more lesions
  • Pustular form
  • Folliculitis
  • Hyperkeratosis
  • Painful, not pruritic unless secondary
  • Even sepsis, death
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19
Q

Pododemodecosis

A
  • Do NOT scratch as much
  • Manifestation or sequalae of generalized form
  • Least common form of disease
  • *usually all 4 paws
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20
Q

Demodecosis: young animals (3-18 months), localized and generalized form

A
  • Localized: excellent prognosis (self-recovery)
  • Generalized: depends on history and family, good prognosis with treatment
21
Q

Demodecosis: older animals (>1.5 years), generalized form

A
  • Often underlying immune deficiency, concurrent disease, reproductive stress
  • Poor prognosis, difficult to treat
22
Q

Demodecosis treatment

A
  • Isoxazolines, moxidectin
  • Antibiotics, nutritional support, grooming
  • Do NOT use parents or pups for breeding
23
Q

Feline demodecosis (RARE): D. cati

A
  • Eyelids, head, neck
  • Localized often resolves spontaneously
  • Generalized: check for underlying disease (FLV, FIV)
24
Q

Feline demodecosis (RARE): D. gatoi

A
  • Pruritic, contagious
  • Often no underlying disease
  • *show and pedigree cats
25
Q

Surface mites: types

A
  • Cheyletiella spp: rabbit fur mite (walking dandruff)
  • Otodectes sp: ear mite
  • Eutrombicula spp.: harvest mite
26
Q

Cheyletiella spp.

A
  • Contagious within and among species
  • Zoonotic
27
Q

C. yasguri: species

A
  • Dogs
28
Q

C. blakei: species

A
  • Cats
29
Q

C. parasitivorax: species

A
  • Rabbits
  • common
30
Q

Cheyletiella adult

A

*contagious among species
- PALPAL CLAWS
- Can survive in cool environment for more than 10 days

31
Q

Cheyletiella clinical signs

A
  • Often subclinical
  • Starts as dorsal scaling
  • +/- MILD pruritis, hair loss
  • Rarely: hypersensitivity, miliary dermatitis, dorsal hypotrichosis
  • Ex. Harvey and McKeever skin diseases
32
Q

Human Cheyletiella infestation

A
  • Self limiting
  • Red spots where ‘animals’ are being held
33
Q

Otodectes cynotis (CATS, dogs): ear mites

A
  • 50% of otitis cases in cats
  • <10% of otitis cases in dogs
  • *highly contagious, usually not zoonotic (transient)
34
Q

Otodectes adults

A
  • Longer legs
  • Can survive in cool, humid environments for months
  • Short pedicel or stalk
  • Caruncle or sucker=close
35
Q

Otodectes mites: clinical signs

A
  • Not always restricted to ears: can be SYSTEMIC
  • Pruritus, shaking, behavioural disturbances (hypersensitivity)
  • Worse in young and immunocompromised
36
Q

Eutrombicula spp. (NA, harvest mite or chigger)

A
  • Free living mites
  • Only LARVAE PARASITIC (wide range of hosts)
  • *zoonotic (from environment, NOT host-host)
  • Seen mostly in fall
  • RARE
37
Q

Eutrombicula spp. larva

A
  • *ONLY 6 legs!
  • Plumose setae (‘feather’): bright red=see with naked eye
38
Q

Eutrombicula clinical signs

A
  • Larvae around eyes
  • Head, eyes, ears
  • Feet
  • Ventrum
  • Can be mild-severe pruritus associated with stylostome (feeding tube)
  • Infestation transient
39
Q

Diagnosis of burrowing mites

A
  • Multiple, deep skin scrapings +/- KOH digest
  • Biopsy?
40
Q

Diagnosis of surface mites

A
  • Tape
  • Comb
  • Vacuum
  • Hand lens
  • Fecal (cats!)
41
Q

Diagnosis: ear/nose

A
  • Otoscopy/rhinoscopy and swab (mineral oil)
42
Q

What do you treat with?

A
  • Macrocyclic lactones (oral, topical, paraenteral)
    o Ivermectin, selamectin
  • Isoxazolines (oral)
43
Q

Mange management: Cheyletiella

A
  • Treat all animals in contact
  • Zoonotic
  • Can survive in environment (>10days)
44
Q

Mange management: Otodectes

A
  • Treat all in contact with dogs and cats
  • Zoonotic (rare, transient)
  • Can survive in environment (months)
45
Q

Mange management: Eutrombicula

A
  • Don’t need to treat others, unless same source exposure
  • Zoonotic (from environment)
  • Can survive in environment (most of life cycle outdoors)
46
Q

Mange management: Sarcoptes

A
  • Treat all in contact
  • Zoonotic (transient)
  • Can survive in environment (weeks)
47
Q

Mange management: Notedres

A
  • Treat all in contact with cats
  • Zoonotic (transient)
  • Can NOT survive in environment
48
Q

Mange management: Demodex

A
  • Only treated affected
  • Not zoonotic
  • Do NOT survive in environment

PARASITOLOGY - 1 (14 decks)

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