arthropods - mites - prostigmatids Flashcards
progstigamatid mites characteristics
stigmata in front of legs
palpal claws
body shape - cigar shapes
mesostigmatid mites characteristics
stigmata located mid-body
peritreme: breathing tube, opens at stigma and runs anteriorly
legs: all originate from anterior 1/2 of body; tarsal claws at ends of legs
astigmatid mites charcterisitcs
no stigmata
legs: 2 anterior pairs, 2 posterior pairs, tarsal suckers on pedicels
mite life cycle
egg
larva - 3 pairs of legs
nymphs - some species have >1 nymph stage
adult
-PPP = 2 to 4 weeks
-adults live 2wks to 2 months
-adult females lay 1-5 eggs per day after mating
-most mites live entire life ON host
mite transmission
-direct contact: animal to animal; close, skin to skin
mite patho
-most mites invade skin
-some invade ear canal, nasal cavity, lungs
-patho results from mite activity:
mites burrowing and biting
depositing eggs
hypersensitivity reaction to mites
clinical signs for skin mites
-dermatitis: “mange”
skin inflammation – erythema (redness)
may be pruritus (itchiness)
clinical signs for skin mites
-dermatitis: “mange”
skin inflammation – erythema (redness)
may be pruritus (itchiness)
self trauma due to scratching
alopecia
crust/scabs
-secondary skin infections common
other clinical signs
ear canals: ear pruritus, dark/dry/crusted debris
nasal cavity: sneezing, head shaking, rhinitis, pawing at ease, epistaxis
lungs: parasitic pneumonitis, cough, dyspnea
skin mite diagnosis
- skin scraping: deep scrape for demoted; superficial for sarcoptes and others
- hair pluck = trichogram
- acetate tape prep: superficial mites
- fecal float: may see mites ingested with grooming
- skin cytology
ear mite diagnosis
-otoscope: may visualize mites moving
-microscope exam of ear debris; macerate ear debris in mineral oil and cover slip
mite treatment and control
-topical and systemic options
-consider life cycle: often need >1 treatment, re-treat in 2-4 weeks
demodex host - prostigamatid mite
many mammals
SA: dogs, cats
LA too host specific
demodex site
skin: hair follicles, sebaceous glands
often head, limbs
demodex clinical signs
demodicosis, demodectic mange
alopecia, often not itchy
LA: nodules
secondary skin infection common - may be itchy then
demodex diagnosis
-deep skin scraping, hair pluck, fecal float
-long, cigar, shape
-4 pairs of stubby legs
cheyletiella mite host - prostigmatid
cats, rabbits, dogs
cheyletiella site
skin, haircoat
cheyletiella clinical signs
walking dnadruff
mild pruuritus
often starts on dorsum
cheyletiella diagnosis
examine haircoat
acetate tape preparation
fecal float
cheyletiella treatment
can live off host several days
treat host + environemnt
sarcoptes mite host - astigmatid
many: host-adapted species
SA: dogs, cats, rabbits, ferrets
LA: horses, cattle, pigs
people – zoonotic
sarcoptes site
skin
distribution: ear margins, lateral tarsi and elbows
sarcoptes clinical signs
sarcoptic mange:
intense pruritus, alopecia, crust, erythema
sarcoptes diagnosis
superficial skin scraping
-difficult to find
-globose body
-pedicels: long, unsegmented
-anus located terminally
psoroptes host - astigmatid
cattle, horses, sheep, goats
special species: rabbits
psoroptes site
LA - skin; especially tail region, shoulders
rabbits - skin: ears (pinnae)
psoroptes clinical signs
psoroptic mange
-pruritus
-dermatitis: alopecia, crusting, erythema
psoroptes diagnosis
skin scraping
-pedicels: long
-segmented: 3 segments
octodectes host - astigmatid
cats, dogs, ferrets, foxes
octodectes site
ear canals
octodectes clinical signs
ear pruritus
otitis externa: otic debris dark and try
octodectes diagnosis
microscope exam of ear debris in mineral oil
-mites and eggs
-pedicels: short, unsegmented
chorioptes host - astigmatid
LA: cattle, horses, sheep, goats
special species: rabbits
chorioptes site
LA: skin; especially tail, legs
rabbits: skin – ears (pinnae)
chorioptes clinical signs
chorioptic mange
-pruritus (variable)
-dermatitis: alopecia, crusts, erythema
chorioptes diagnosis
skin scraping
-pedicels: short, unsegmented
knemidokoptes host - astigmatid
birds
knemidokoptes site
skin: face, legs
knemidokoptes clinical signs
-proliferative, crusted lesions
-legs, base of beak, vent
-characteristic lesions
knemidokoptes diagnosis
-microscopic exam of skin crusts
-skin scraping
-mites have globose shape
-pedicels: females - none, males - long, unsegmented
notoedres host - astigmatid
cats, rabbits, rats
notoedres site
skin - ears, face, distal extremities
notoedres clinical signs
intense pruritus
crusting
alopecia
notoedres diagnosis
skin scraping
-pedicels: long, unsegmented
-anus located dorsally
