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Created page with '*Causes psoroptic skin infestation '''Recognition''' *Oval shaped *Long legs *Funnel shaped suckers on '''segmented'…'
*Causes [[Parasitic skin infections - Pathology#Psoroptic mites|psoroptic skin infestation]]
'''Recognition'''
*Oval shaped
*Long legs
*Funnel shaped suckers on '''segmented''' pedicels
*1-2mm in length
'''Life cycle'''
*Confined to skin surface
*Feed on serous exudate by siphoning
*Adult female can lay up to 100 eggs during her life time (1 month)
*10 day life cycle
*2 nymphal stages
====''Psoroptes cuniculi''====
*Parasite of rabbits
*Common among conventional rabbits
*Transmitted via contact
*Adapted to living in an aural environment
'''Pathogenesis'''
*The ears are painful and intensely pruritic
*Affected rabbits shake their heads and scratch their ears
*The inner surfaces of the pinnae are covered with brown, scaly, fetid material, and the skin beneath is raw
*Mites are grossly visible
*Histologically, there is chronic erosive and proliferative eosinophilic dermatitis
**The mites are non-burrowing and thus are found only in the exudate, not in the tissue
'''Diagnosis'''
*Microscopic examination for mites (low magnification)
*Appearance
'''Control'''
*Infestations are difficult to eliminate from a colony
**Ivermectin is usually effective
====''Psoroptes ovis''====
*Adult females are large mites at 750μm in length
*Males identified by copulatory suckers and paired posterior lobes
*Males attach to deutonymphs (second moult after larval stage) in a process called '''copula'''
**Males remain in copula until females moult for the last time
**Copulation occurs
*Life cycle last '''14 days'''
*Transmitted by direct contact between sheep
*Indirect transmission can also occur
'''Pathogenesis'''
*Economically important ectoparasite of sheep
*Causes '''sheep scab'''
**Wool loss, restlessness, biting, scratching of infested area and decreased productivity through decreased weight gain
**Usually seen in '''late autumn''' and '''early winter''' (although may also occur in late summer)
**Population numbers decline after shearing due to a change in the micro-climate, then build up again as the fleece grows
**'''Notifiable in UK'''
*Mites found under scabs and in skin folds
*Lesions most common on flanks, neck, back and shoulders
*Causes pruritic condition of cattle
*Active in keratin layer
*Mouthparts abrade the skin
*Antigenic material in mite faeces can lead to hypersensitivity reactions
'''Diagnosis'''
*Skin scraping
*KOH added
*Warm slide over a bunsen flame
*Examine under a microscope
'''Treatment'''
*Sheep
**Plunge dipping; no less than 1 minute and must dip head at lease once
**Can treat with avermectins or milbemycins by injection
*Cattle, horses and rabbits
**No licensed product for horses in the UK
**Cattle and rabbits can be treated with avermectins, milbemycins or topical acaricides
'''Recognition'''
*Oval shaped
*Long legs
*Funnel shaped suckers on '''segmented''' pedicels
*1-2mm in length
'''Life cycle'''
*Confined to skin surface
*Feed on serous exudate by siphoning
*Adult female can lay up to 100 eggs during her life time (1 month)
*10 day life cycle
*2 nymphal stages
====''Psoroptes cuniculi''====
*Parasite of rabbits
*Common among conventional rabbits
*Transmitted via contact
*Adapted to living in an aural environment
'''Pathogenesis'''
*The ears are painful and intensely pruritic
*Affected rabbits shake their heads and scratch their ears
*The inner surfaces of the pinnae are covered with brown, scaly, fetid material, and the skin beneath is raw
*Mites are grossly visible
*Histologically, there is chronic erosive and proliferative eosinophilic dermatitis
**The mites are non-burrowing and thus are found only in the exudate, not in the tissue
'''Diagnosis'''
*Microscopic examination for mites (low magnification)
*Appearance
'''Control'''
*Infestations are difficult to eliminate from a colony
**Ivermectin is usually effective
====''Psoroptes ovis''====
*Adult females are large mites at 750μm in length
*Males identified by copulatory suckers and paired posterior lobes
*Males attach to deutonymphs (second moult after larval stage) in a process called '''copula'''
**Males remain in copula until females moult for the last time
**Copulation occurs
*Life cycle last '''14 days'''
*Transmitted by direct contact between sheep
*Indirect transmission can also occur
'''Pathogenesis'''
*Economically important ectoparasite of sheep
*Causes '''sheep scab'''
**Wool loss, restlessness, biting, scratching of infested area and decreased productivity through decreased weight gain
**Usually seen in '''late autumn''' and '''early winter''' (although may also occur in late summer)
**Population numbers decline after shearing due to a change in the micro-climate, then build up again as the fleece grows
**'''Notifiable in UK'''
*Mites found under scabs and in skin folds
*Lesions most common on flanks, neck, back and shoulders
*Causes pruritic condition of cattle
*Active in keratin layer
*Mouthparts abrade the skin
*Antigenic material in mite faeces can lead to hypersensitivity reactions
'''Diagnosis'''
*Skin scraping
*KOH added
*Warm slide over a bunsen flame
*Examine under a microscope
'''Treatment'''
*Sheep
**Plunge dipping; no less than 1 minute and must dip head at lease once
**Can treat with avermectins or milbemycins by injection
*Cattle, horses and rabbits
**No licensed product for horses in the UK
**Cattle and rabbits can be treated with avermectins, milbemycins or topical acaricides