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| + | *Occurs in cattle, sheep, horses, goats, rabbits and other animals |
| − | Also Known as: '''''Sheep Scab — Psoroptic Scabies — Psoroptosis'''''
| + | *Host-specific |
| − | | + | *[[Psoroptes cuniculi|''Psoroptes cuniculi'']] in ear canals of rabbits, horses, goats and sheep |
| − | == Introduction ==
| + | *[[Psoroptes|''P.equi'']] at base of mane, tail and forelock in horses |
| − | | + | *[[Psoroptes ovis|''P.ovis'']] in sheep ('''sheep scab''')and cattle |
| − | Psoropitc mange is the disease caused by the '''non-burrowing''' mite, ''[[Psoroptes ovis]] ''(common name Scab mite), which affects sheep.
| + | **Thickened skin and dry scales and crusts |
| − | | + | **Starts at withers and spreads due to self trauma |
| − | Other species of Psoroptes mite affect a variety of species including cattle, goats, horse, rabbit, camelid, however, all mites are host specific.
| + | **Microscopically: |
| − | | + | ***Spongiotic, hyperplastic or exudative superficial perivascular dermatitis |
| − | == Pathogenesis ==
| + | ***Eosinophils[[Category:To_Do_-_Clinical]] |
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| − | The mite is active in the keratin layer of the skin and has abrasive mouthparts. It feeds on exudate of lymph, skin cells and bacteria caused by a [[Hypersensitivity - Introduction|hypersensitivity reaction]] to antigenic mite faeces by the host. This causes '''intense pruritus''', leading to self trauma, crust and scale formation and inflammation.
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| − | It is not only economically important to the sheep industry due to poor fleece quality and weight loss, but it can also pre-dispose to life-threatening condition such as [[Blowfly Strike|Blowfly strike]], as the [[Calliphoridae|blowflies]] find the damaged skin ideal for egg laying.
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| − | The disease is most prevalent in autumn and winter months, however does still occur in the summer, especially in sheep that have not been shorn.
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| − | Psoroptic mange in sheep '''used to be a notifiable ''''''disease '''in the UK, but has been de-regulated since 1992.
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| − | == Clinical Signs ==
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| − | '''Severe pruritus and '''evidence of '''self-trauma '''(loss, damage or staining of wool) are the main signs to notice from within the herd. Once a closer inspection is made, inflammation and an exudate will be noticed on the skin and areas of yellow crust will also be present. In on-going cases,'''weight loss''' in adults, or reduced weight gain in growing animals, will be seen due to the irritation causing them to have a reduced feed intake. In some cases, secondary '''blowfly strike '''may by the first sign noticed, when the sore traumatised skin has become a perfect breeding ground for the blowfly.
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| − | == Diagnosis ==
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| − | History and clinical signs are often enough to make presumptive diagnosis. Skin scraping to microscopically identify mites (low magnification) should be performed. Mites are found under scabs and in skin folds.
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| − | == Treatment/ Control ==
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| − | Infestations are difficult to eliminate from a flock so a key factor in control is to not allow it to enter - new stock should be isolated for at least three weeks before mixing with the main flock.
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| − | *'''Plunge dipping is curative and preventative''' | |
| − | The dip must contain the '''Organophosphate, diazinon '''or the '''Synthetic Pyrethroid, cis-cypermethrin. '''The sheep must be dipped for '''at least one minute '''and the head should be fully submerged twice during this time. The sheep must be kept moving when in the dip as the movement displaces air from the fleece allowing better penetration
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| − | ''Psoroptes'' can be treated with avermectins or milbemycins by injection, but only moxidectin has any prophylactic effect. Two injections 7 days apart or one single dose (doramectin only) are needed. <br>
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| − | == Other species ==
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| − | '''Cattle'''
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| − | Psoroptic mange is uncommon in cattle in the UK. When present, it affects mainly the withers and can be treated with avermectin, milbemycins or topical acaracides.
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| − | '''Horses'''
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| − | Equine Psoroptic mange is '''notifiable in the UK''', but has not been recorded for many years. There are no licensed products for treatment of horses in the UK.
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| − | '''Rabbits'''
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| − | Rabbits become infected by ''[[Psoroptes cuniculi]]'' causing [[Mites – Rabbit#Psoroptiasis|'Ear canker']]. The external auditory canal infection is often asymptomatic, but may cause scratching and head shaking behaviour. It can be treated with avermectin, milbemycins or topical acaracides. For more information see the [[Mites – Rabbit#Psoroptiasis|rabbit section]].
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| − | {{Chapter}}
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| − | {{Mansonchapter
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| − | |chapterlink = http://www.mansonpublishing.co.uk/book-images/9781840760491_sample.pdf
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| − | |chaptername = Sheep Scab
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| − | |book = Sheep Medicine
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| − | |author = Philip R. Scott
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| − | |isbn = 9781840761498
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| − | }}
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| − | == References ==
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| − | Aitken, I.D, (2007) '''Diseases of Sheep fourth edition,''''' Blackwell Publishing ''
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| − | Fox, M and Jacobs, D. (2007) '''Parasitology Study Guide Part 1: Ectoparasites,''''' Royal Veterinary College ''
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| − | Hindson, J.C, (2002)''' Manual of Sheep Diseases second edition,''''' Blackwell Publishing ''
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| − | Taylor, M.A, Coop, R.L, Wall, R.L, (2007) '''Veterinary Parasitology third edition,''''' Blackwell Publishing ''
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| − | {{review}}
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| − | {{OpenPages}}
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| − | [[Category:Expert_Review - Farm Animal]][[Category:Expert Review - Horse]] [[Category:Integumentary_System_-_Mite_Infections]][[Category:Dermatological Diseases - Sheep]][[Category:Dermatological Diseases - Cattle]][[Category:Dermatological Diseases - Horse]]
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