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'''[[Burrowing Mites]]'''
 
'''[[Burrowing Mites]]'''
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==Non-Burrowing Mites==
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'''[[Non-Burrowing Mites]]
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*Live on the skin surface
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*Feed on either skin scales and tissue or suck blood
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===''Psoroptes''===
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*Causes [[Parasitic skin infections - Pathology#Psoroptic mites|psoroptic skin infestation]]
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'''Recognition'''
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*Oval shaped
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*Long legs
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*Funnel shaped suckers on '''segmented''' pedicels
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*1-2mm in length
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'''Life cycle'''
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*Confined to skin surface
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*Feed on serous exudate by siphoning
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*Adult female can lay up to 100 eggs during her life time (1 month)
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*10 day life cycle
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*2 nymphal stages
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====''Psoroptes cuniculi''====
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*Parasite of rabbits
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*Common among conventional rabbits
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*Transmitted via contact
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*Adapted to living in an aural environment
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'''Pathogenesis'''
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*The ears are painful and intensely pruritic
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*Affected rabbits shake their heads and scratch their ears
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*The inner surfaces of the pinnae are covered with brown, scaly, fetid material, and the skin beneath is raw
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*Mites are grossly visible
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*Histologically, there is chronic erosive and proliferative eosinophilic dermatitis
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**The mites are non-burrowing and thus are found only in the exudate, not in the tissue
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'''Diagnosis'''
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*Microscopic examination for mites (low magnification)
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*Appearance
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'''Control'''
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*Infestations are difficult to eliminate from a colony
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**Ivermectin is usually effective
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====''Psoroptes ovis''====
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*Adult females are large mites at 750μm in length
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*Males identified by copulatory suckers and paired posterior lobes
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*Males attach to deutonymphs (second moult after larval stage) in a process called '''copula'''
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**Males remain in copula until females moult for the last time
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**Copulation occurs
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*Life cycle last '''14 days'''
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*Transmitted by direct contact between sheep
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*Indirect transmission can also occur
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'''Pathogenesis'''
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*Economically important ectoparasite of sheep
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*Causes '''sheep scab'''
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**Wool loss, restlessness, biting, scratching of infested area and decreased productivity through decreased weight gain
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**Usually seen in '''late autumn''' and '''early winter''' (although may also occur in late summer)
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**Population numbers decline after shearing due to a change in the micro-climate, then build up again as the fleece grows
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**'''Notifiable in UK'''
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*Mites found under scabs and in skin folds
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*Lesions most common on flanks, neck, back and shoulders
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*Causes pruritic condition of cattle
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*Active in keratin layer
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*Mouthparts abrade the skin
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*Antigenic material in mite faeces can lead to hypersensitivity reactions
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'''Diagnosis'''
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*Skin scraping
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*KOH added
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*Warm slide over a bunsen flame
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*Examine under a microscope
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'''Treatment'''
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*Sheep
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**Plunge dipping; no less than 1 minute and must dip head at lease once
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**Can treat with avermectins or milbemycins by injection
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*Cattle, horses and rabbits
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**No licensed product for horses in the UK
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**Cattle and rabbits can be treated with avermectins, milbemycins or topical acaricides
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===''Chorioptes bovis''===
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*These cause [[Parasitic skin infections - Pathology#Chorioptic mites|parasitic skin infestation]]
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*Surface parasite of horses and cattle
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*Less pathogenic than ''Psoroptes''
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**Mouthparts cannot pierce the skin
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*Life cycle takes '''3 weeks'''
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'''Recognition'''
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*Oval body
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*Long legs
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*Cup shaped suckers on '''unsegmented''' pedicels
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*Females about 300μm in length
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'''Pathogenesis'''
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*Chorioptic mange
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**Often seen in rough-legged horses with heavy feathering
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**Induce crusty skin and lesions below the hocks and knees
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*Mild condition in cattle
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**Rubbing and scratching
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**Hide damage
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**Usually affects the base of the tail, perineum and udder
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*Usually found on legs of sheep
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**Mild condition
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===''Otodectes cynotis''===
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*Causes [[Parasitic skin infections - Pathology#Otodectic mites|otodectic skin infestation]]
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*Commonest mange of dogs and cats in the world
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*Inhabits the inner ear
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*Also found in the fox and the ferret
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*Closed keratinous bars ('''apodemes''') on ventral surface
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*Life cycle takes '''3 weeks'''
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*Feeds on ear debris
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'''Pathogenesis'''
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*The majority of cats harbour the mites, however only a few show symptoms
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**Transmission occurs whilst kittens are suckling
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*Common cause of [[Otitis Externa - Small Animal|otitis externa]] in dogs
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*Brown waxy exudate produced
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*Can lead to secondary infection
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*Clinical signs are apparent
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**Head shaking
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**Ear scratching
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**Aural haematomata
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'''Treatment'''
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*Acaracidal ear drops
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**Massage base of ear to disperse drops after treatment
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*Most treatments need to be repeated in 10-14 days to kill newly hatched mites
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*Selamectin can be used as a spot-on treatment
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**Prolonged duration of action
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*Treat all in-contact animals
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**These may be asymptomatic carriers
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===''Cheyletiella spp.''===
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*Surface mite of cats and dogs
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*Also found on humans and rabbits
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**''C.yasguri'' (dogs)
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**''C.blakei'' (cats and humans)
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**''C.parasitivorax'' (rabbits)
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*Causes [[Parasitic skin infections - Pathology#Cheyletiellosis|parasitic skin infestation]]
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'''Recognition'''
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*Waisted body
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*Claw like palps on head
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*Combs at ends of legs
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'''Pathogenesis'''
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*Highly contagious
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*Mild pathogenesis
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*Causes very scaly dermatitis
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*Can be transferred to humans
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'''Diagnosis'''
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*Clinical signs
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**Excess scurf
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*Brush scurf onto dark paper
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**'Walking dandruff' as mites will move when present in large numbers
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*Skin scrapings
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*Hair pluckings from scaly areas
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**Eggs may be present
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===''Dermanyssus gallinae''===
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*Red mite of poultry
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*Spends most of time '''off''' the host
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**Adults and nymphs visit poultry at night to feed
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*Life cycle takes '''1 week'''
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*Adults can survive several months without feeding so reservoirs can build up
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'''Appearance'''
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*Spider like mite with long legs
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*White or grey
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**Becomes red when engorged with blood after feeding
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*Few hairs on body
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*Hooks on legs
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'''Pathogenesis'''
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*Blood sucking mite
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*Lesions usually found on the breast and legs
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*Irritation, restlessness, decrease in egg production
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*Anaemia can result if mites are present in large numbers
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*Newly hatched chicks can rapidly die if infested
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'''Treatment'''
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*Acaricide
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*Environmental treatment
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*Remove wild bird nests
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===''Ornithonyssus''===
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*Also called the Northern mite or Northern feather mite
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*Closely related to ''Dermanyssus''
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*Hairy
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*Spends entire life cycle '''on''' the host
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*Occurs in caged birds and poultry
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*Causes feathers to become matted and severe scabbing can develop
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**Scabs particularly seen around the vent
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*Decreases egg production
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*Grey or black discolouration of feathers when large numbers of mites are present
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===''Trombicula autumnalis''===
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*Causes [[Parasitic skin infections - Pathology#Trombiculidiasis|parasitic skin infestation]]
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*Also called the harvest mite
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*Not host-specific
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**Will parasitise any animal, including humans
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*Only the larval stage is parasitic
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**Nymphal and adult stages are free-living in the soil
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*Mite numbers are highest in late summer in temperate climates
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**Mite numbers are constant all year in tropical regions
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'''Recognition'''
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*Six legs
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*Bright orange in colour
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*Hairy
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*No spiracles
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**Breath through cuticle
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'''Pathogenesis'''
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*Larvae insert mouthparts into skin and inject cytolytic enzymes
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*Feed on partly digested host tissue
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*Causes irritation
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*Can cause a hypersensitivity reaction
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*Mites found on head, ears and flanks of pets
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*Mites found on face and limbs of grazing animals (depending upon host height)
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'''Control'''
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*Very difficult; try to restrict access of animals to 'hot-spot' areas
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'''Treatment'''
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*Fipronil spray applied to affected areas
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===''Leporacarus''===
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*Known as the rabbit fur mite
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*Found on rabbits (domestic and wild) and on hares
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*Common
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*Clings to individual hairs
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*Feeds on sebaceous secretions and skin debris
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*Non-pathogenic
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*May cause dermatitis in humans handling infected animals
       
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