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99 Cards in this Set
- Front
- Back
Kingdom
Phylum Class Order |
Animalia
Arthropoda Arachnida Acarina |
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Four sub-orders of Acarina
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1. Ixodoidea
2. Mesostigmata 3. Prostigmata 4. Astigmata |
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Mites vs ticks
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Resemble ticks but smaller
Do not have a hypostome with rows of teeth Abundant, most free living |
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Stigmata
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Respiratory openings
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Body divisions
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Capitulum with palps and chelicerae, and idiosoma
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Life cycle of mites
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Egg, larva, nymphs (proto-, dueto-, trito-), adults
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What kind of parasites are mites?
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Can be intermittent parasites in nests or burrows, or permanent parasites
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Where can mites be found on a host?
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On skin, in ears or respiratory system
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Effect of mites on host
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Blood loss
Irritation Hair loss Scab formation Vectors of viruses and protozoans |
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Which of the four sub-orders of Acarina refer to mites?
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Mesostigmata (Gamasid mites)
Prostigmata (Trombidiform mites) Astigmata (Mange mites) |
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Mesostigmata |
Gamasid mites Legs at anterior end of body Many free-living |
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Prostigmata
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Stigmata on capitulum at base of chelicerae Chelicerae adapted for piercing Feather-like setae |
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Astigmata
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Stigmata absent
Front pairs of legs separated from back pairs |
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Main genera of Mesostigmata
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Dermanyssus
Ornithonyssus |
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Dermanyssus gallinae
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Dermanyssus gallinae
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Red mite of poultry
Very common Triangular anal plate Nocturnal blood feeders Spend most of life in environment |
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Hosts of Dermanyssus gallinae
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Birds & mammals
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Life cycle of Dermanyssus gallinae
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Eggs, larva, 2 nymphs
Eggs laid in crevices Life cycle 7 days |
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Pathogenesis of Dermanyssus gallinae
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Anaemia
Irritation Transmit Borrelia anserina |
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Control of Dermanyssus gallinae
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Removal of rubbish and all shelter for mites and spraying with 1% malathion
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Ornithonyssus spp
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Ornithonyssus spp
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Fowl mites, referred to as 'starling lice' Two species: O. bursa, O. sylviarunOval anal plate Feed on birds while in nest Some on birds all the time Blood feeders Not host specific |
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On which hosts are Ornithonyssus spp common on?
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Wild birds
Found in bird nests |
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Pathogenesis of Ornithonyssus spp.
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O. bursa:
Hypersensitivity on man and animals Can kill newly hatched chickens and adult birds Commonly puts birds off the lay O. sylviarum: Irritation, anaemia, low fertility in roosters |
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Other mesostigmatid mites
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May be uncommon or non-pathogenic
Nasal mite of the dog: Pneumonyssoides caninum Ear mite of cattle: Raillietia auris Snake mite: Ophionyssus natricis Canary lung mite: Sternostoma tracheacolum |
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Main genera of Prostigmata
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Trombicula
Demodex PsorergatesCheyletiella |
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Trombicula spp.
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Trombicula
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Chiggers, harvest mites
Only larvae are parasitic Attach in clusters Often yellow or orange Transmit scrub typhus (Rickettsia australis) T. sarcina causes black soil itch in Qld |
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Demodex canis |
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Features of Demodex canis
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Vermiform
Legs very short at front of body |
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Localisation of Demodex canis
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Hair follicles
Feed on cytoplasm |
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Life cycle of Demodex canis
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Egg, 2 nymphs, adults
All stages in hair follicles |
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Transmission of Demodex canis
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Contact during suckling
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Demodectic mange
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Demodectic mange
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All dogs infected, only some develop disease
Short-haired dogs with CMI deficiency Mainly 6-10 months of age Predilection sites: eyes, ears, muzzle Secondary infection with Staph. albus Infection of follicles leads to hair loss & hyperkeratosis Disease can be: - localised or generalised - squamous or pustular (secondary infection) |
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Diagnosis and treatment of Demodectic mange
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Deep skin scraping Amitraz Ivermectin |
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Other species of Demodex
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Uncommon or rarely pathogenic
Each host has "own" species Pig: - D. phylloides - lesions mainly on head Cattle: - D. bovis - damages hide Sheep, goats, horse: - D. ovis, D. caprae, D. equi - rare Man: - D. folliculorum - prevalence 50% - common in blackheads - base of eyelashes |
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Psorergates ovis
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Psorergates ovis features
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The sheep itch mite Tiny miteCircular with legs arranged radially Legs very short Lives in superficial layers of dermis |
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Psorergates ovis host
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Affects sheep in Australia, Africa, N&S America
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Life cycle of Psorergates ovis
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Egg, Larva, 3 nymphs, adults
Length: 5 weeks |
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Transmission of Psorergates ovis
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Contact (suckling, shearing)
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Predilection sites of Psorergates ovis
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Sides, between hip & shoulder near mid-line
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Seasonal occurance of Psorergates ovis
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Most abundant in winter
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Effect of Psorergates ovis on host
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Hypersensitivity causes irritation
Rubbing - pulled wool Not all sheep affected Spreads slowly in mob |
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Diagnosis & treatment
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Skin scraping
Control can be by OPs, amitraz or ivermectin None will totally eliminate mite Ivermectin better in spring when mites are reproducing actively OPs with amitraz good during quiescent phase |
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Cheyletiella spp
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Cheyletiella genus features
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Palpi short and strong
Strong claws on palps |
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Cheyletiella species
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Rabbits: Cheyletiella parasitivorax
Dogs: Cheyletiella yasguri Cats: Cheyletiella blakei |
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Effects of Cheyletiella spp on host
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Mild mange, often around head
Also bite humans |
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Two families of Astigmata mites
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Sarcoptidae
Psoroptidae |
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A = Sarcoptidae
B = Psoroptidae |
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Sarcoptidae features
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Rear legs very short
Burrow in upper layers of skin |
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Psoroptidae features
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Rear legs project
Tissue fluid feeders cause scabs |
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Sarcoptidae genera
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Sarcoptes
Notoedres Trixacarus Cnemidocoptes |
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Psoroptidae genera
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Psoroptes
Otodectes Chorioptes |
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Sarcoptes scabiei
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Features of Sarcoptidae family
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Body round Legs 3 and 4 usually do not project beyond body margin |
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Features of Sarcoptes scabiei
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Triangular scales on dorsum
Wide host range Strains on specific hosts Can survive but not reproduce on other hosts |
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Life cycle of Sarcoptes scabiei
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Lives in superficial layers of skin
Lay eggs in tunnel Larva and 2 nymphal stages Length: 10-17 days |
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How long can Sarcoptes scabiei mites survive off host?
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Few days
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Transmission of Sarcoptes scabiei
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Contact
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Sarcoptes scabiei inside epidermis
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Pathogenesis of Sarcoptes scabiei
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Burrowing mites cause irritation
Intense pruritis Hyperkeratosis Alopecia Lesions begin on face, extend over body Secondary infection, pustules Self inflicted trauma Hypersensitivity |
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Diagnosis of Sarcoptes scabiei
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Skin scrapings
Can be difficult to find mites |
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Treatment of Sarcoptes scabiei
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Most insecticides
Topical only as sarcoptes mites don't feed on blood |
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Sarcoptes scabiei hosts
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Dogs
Other: Pigs, camels, ferrets, wombats, pigs, humans |
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Other sarcoptid genera on mammals
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Guinea pigs: Trixacarus caviae
Cats & rabbits: Notoedres cati Rodents: Notoedres muris |
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Cnemidocoptes spp
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Cnemidocoptes species
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Cnemidocoptes gallinae
Cnemidocoptes mutans Cnemidocoptes pili |
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Cnemidocoptes features
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Sarcoptid mites of birds Legs very shortFound on birds |
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Where is Cnemidocoptes gallinae found?
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In feathers
Depluming mite of poultry |
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Where is Cnemidocoptes mutans found?
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On legs of chickens
"Scaly leg" |
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Scaly leg
Caused by Cnemidocoptes mutans |
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Where is Cnemidocoptes pili found?
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On beak and legs of psittacines
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Cnemidocoptes pili on beak and legs
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Features of Psoroptidae family
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Body oval
Legs 3 & 4 project beyond body margin Mites don't burrow, but cause scab formation Tissue fluid feeders |
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Genera of Psoroptidae
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Otodectes : ear mite of cats and dogs
Psoroptes: mites of rumnants, horses Chorioptes: mites of ruminants and horses |
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Differentiating between psoroptes and chorioptes
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Psoroptes have jointed pedicels
Chorioptes have simple pedicels |
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A = Psoroptes (jointed)
B = Chorioptes (simple) |
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Otodectes cynotis
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Otodectes cynotis hosts
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Common ear mite of dogs and cats
Also occurs in foxes and rabbits |
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Pathogenesis of Otodectes cynotis
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Causes scabs in external ear canal
Hosts shake heads and rub ears May get fever and depression in cats |
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Transmission of Otodectes cynotis
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Transmitted by contact, often while suckling
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Diagnosis of Otodectes cynotis
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With otoscope, unreliable
Examine exudate under microscope |
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Treatment of Otodectes cynotis
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Oral or topical insecticides
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Psoroptes species
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Sheep scab mite: Psoroptes ovis
Ear mite: Psoroptes cuniculi Psoroptes equi Psoroptes natalensis |
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Psoroptes ovis
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Psoroptes ovis features
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Large mite
Lives under scabs Feeds on tissue fluids Life cycle 9-10 days High biotic potential Most abundant in cool weather |
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Pathogenesis of Psoroptes ovis
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"Sheep scab" (but affects cattle too) IrritationScabs Hypersensitivity Emaciation, high mortality |
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What areas of the animal does Psoroptes ovis affect?
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Starts on shoulders and back, spreads over whole body
In latent cases can occur in ears, inguinal folds, interdigital spaces |
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How common is Psoroptes ovis?
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Common in most countries
Eradicated from Australia |
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Psoroptes cuniculi
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Hosts of Psoroptes cuniculi
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Rabbit, horse, goat, alpaca
Common in lab rabbits |
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Pathogenesis of Psoroptes cuniculi
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Causes ear mange
May spread onto face Causes irritation, shaking of head |
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Chorioptes bovis
(L to R: male, female) |
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Chorioptes bovis hosts
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Cattle, sheep, goats, horses
Commonly seen in housed sheep and cattle |
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Pathogenesis of Chorioptes bovis
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Chorioptic mange
Often referred to as barn itch Can cause scrotal mange in rams |
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Where on the animal does Chorioptes bovis usually occur?
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Mainly on legs and belly
Sits underneath scabs |