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Created page with '*Live on the skin surface *Feed on either skin scales and tissue or suck blood ''Psoroptes'' ===''Chorioptes bovis''=== *These cause [[Parasitic skin infecti…'
*Live on the skin surface

*Feed on either skin scales and tissue or suck blood


[[Psoroptes|''Psoroptes'']]



===''Chorioptes bovis''===

*These cause [[Parasitic skin infections - Pathology#Chorioptic mites|parasitic skin infestation]]

*Surface parasite of horses and cattle

*Less pathogenic than ''Psoroptes''
**Mouthparts cannot pierce the skin

*Life cycle takes '''3 weeks'''


'''Recognition'''
*Oval body

*Long legs

*Cup shaped suckers on '''unsegmented''' pedicels

*Females about 300μm in length


'''Pathogenesis'''
*Chorioptic mange
**Often seen in rough-legged horses with heavy feathering
**Induce crusty skin and lesions below the hocks and knees

*Mild condition in cattle
**Rubbing and scratching
**Hide damage
**Usually affects the base of the tail, perineum and udder

*Usually found on legs of sheep
**Mild condition


===''Otodectes cynotis''===

*Causes [[Parasitic skin infections - Pathology#Otodectic mites|otodectic skin infestation]]

*Commonest mange of dogs and cats in the world

*Inhabits the inner ear

*Also found in the fox and the ferret

*Closed keratinous bars ('''apodemes''') on ventral surface

*Life cycle takes '''3 weeks'''

*Feeds on ear debris


'''Pathogenesis'''
*The majority of cats harbour the mites, however only a few show symptoms
**Transmission occurs whilst kittens are suckling

*Common cause of [[Otitis Externa - Small Animal|otitis externa]] in dogs

*Brown waxy exudate produced

*Can lead to secondary infection

*Clinical signs are apparent
**Head shaking
**Ear scratching
**Aural haematomata


'''Treatment'''
*Acaracidal ear drops
**Massage base of ear to disperse drops after treatment

*Most treatments need to be repeated in 10-14 days to kill newly hatched mites

*Selamectin can be used as a spot-on treatment
**Prolonged duration of action

*Treat all in-contact animals
**These may be asymptomatic carriers


===''Cheyletiella spp.''===

*Surface mite of cats and dogs

*Also found on humans and rabbits
**''C.yasguri'' (dogs)
**''C.blakei'' (cats and humans)
**''C.parasitivorax'' (rabbits)

*Causes [[Parasitic skin infections - Pathology#Cheyletiellosis|parasitic skin infestation]]


'''Recognition'''
*Waisted body

*Claw like palps on head

*Combs at ends of legs


'''Pathogenesis'''
*Highly contagious

*Mild pathogenesis

*Causes very scaly dermatitis

*Can be transferred to humans


'''Diagnosis'''
*Clinical signs
**Excess scurf

*Brush scurf onto dark paper
**'Walking dandruff' as mites will move when present in large numbers

*Skin scrapings

*Hair pluckings from scaly areas
**Eggs may be present


===''Dermanyssus gallinae''===

*Red mite of poultry

*Spends most of time '''off''' the host
**Adults and nymphs visit poultry at night to feed

*Life cycle takes '''1 week'''

*Adults can survive several months without feeding so reservoirs can build up


'''Appearance'''
*Spider like mite with long legs

*White or grey
**Becomes red when engorged with blood after feeding

*Few hairs on body

*Hooks on legs


'''Pathogenesis'''
*Blood sucking mite

*Lesions usually found on the breast and legs

*Irritation, restlessness, decrease in egg production

*Anaemia can result if mites are present in large numbers

*Newly hatched chicks can rapidly die if infested


'''Treatment'''
*Acaricide

*Environmental treatment

*Remove wild bird nests

===''Ornithonyssus''===

*Also called the Northern mite or Northern feather mite

*Closely related to ''Dermanyssus''

*Hairy

*Spends entire life cycle '''on''' the host

*Occurs in caged birds and poultry

*Causes feathers to become matted and severe scabbing can develop
**Scabs particularly seen around the vent

*Decreases egg production

*Grey or black discolouration of feathers when large numbers of mites are present


===''Trombicula autumnalis''===

*Causes [[Parasitic skin infections - Pathology#Trombiculidiasis|parasitic skin infestation]]

*Also called the harvest mite

*Not host-specific
**Will parasitise any animal, including humans

*Only the larval stage is parasitic
**Nymphal and adult stages are free-living in the soil

*Mite numbers are highest in late summer in temperate climates
**Mite numbers are constant all year in tropical regions


'''Recognition'''
*Six legs

*Bright orange in colour

*Hairy

*No spiracles
**Breath through cuticle


'''Pathogenesis'''
*Larvae insert mouthparts into skin and inject cytolytic enzymes

*Feed on partly digested host tissue

*Causes irritation

*Can cause a hypersensitivity reaction

*Mites found on head, ears and flanks of pets

*Mites found on face and limbs of grazing animals (depending upon host height)


'''Control'''
*Very difficult; try to restrict access of animals to 'hot-spot' areas


'''Treatment'''
*Fipronil spray applied to affected areas


===''Leporacarus''===

*Known as the rabbit fur mite

*Found on rabbits (domestic and wild) and on hares

*Common

*Clings to individual hairs

*Feeds on sebaceous secretions and skin debris

*Non-pathogenic

*May cause dermatitis in humans handling infected animals



[[Category:Mites]]
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