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== Introduction ==
== Introduction ==
Psoropitc mange is the disease caused by the '''non-burrowing''' mite, ''Psoroptes ovis ''(common name Scab mite), which affects sheep.
Psoropitc mange is the disease caused by the '''non-burrowing''' mite, ''Psoroptes ovis ''(common name Scab mite), which affects sheep.
Other species of Psoroptes mite affect a variety of species including Cattle, Goats, Horse, Rabbit, Camelid, however, all mites are host specific and will be discussed later.
Other species of Psoroptes mite affect a variety of species including Cattle, Goats, Horse, Rabbit, Camelid, however, all mites are host specific and will be discussed later.
'''Description''': The mite looks very similar in appearance to Chorioptes, being oval in shape with long legs, but is almost visible to the naked eye. It has pointed mouthparts and jointed pedicles which have suckers on the distal aspect.
'''Description''': The mite looks very similar in appearance to Chorioptes, being oval in shape with long legs, but is almost visible to the naked eye. It has pointed mouthparts and jointed pedicles which have suckers on the distal aspect.
'''Life cycle''': Egg- Larvae- Nymph- Adult is confined to the skin surface. This life cycle takes around 10 days to complete. Adult female life expectancy is around one month and she lays 2-3 eggs per day, hence a mite population on an animal can expand rapidly. The mite can survive off the host and so transmission via housing and bedding is possible. Most transmission occurs from direct contact such as at markets or in livestock transporters.
'''Life cycle''': Egg- Larvae- Nymph- Adult is confined to the skin surface. This life cycle takes around 10 days to complete. Adult female life expectancy is around one month and she lays 2-3 eggs per day, hence a mite population on an animal can expand rapidly. The mite can survive off the host and so transmission via housing and bedding is possible. Most transmission occurs from direct contact such as at markets or in livestock transporters.
'''Predilection site''': Lesions are most common on flanks, neck, back and shoulders
This mite is found worldwide, but has been eradicated from Australia and New Zealand.
This mite is found worldwide, but has been eradicated from Australia and New Zealand.
== Pathogenesis ==
== Pathogenesis ==
The mite feeds on exudate of lymph, skin cells and bacteria caused by a hypersensitivity reaction to mite faeces, from the host. This causes intense irritation leading to self trauma, crust and scale formation and inflammation.
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 reaction to antigenic mite faeces, by the host. This causes intense pruritus, leading to self trauma, crust and scale formation and inflammation.
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.
The disease is most prevalent in winter months, however does still occur in the summer, especially in sheep that have not been shorn.
Psoroptic mange in sheep is a '''notifiable disease '''in the UK
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== Clinical signs ==
== Clinical signs ==
*Severe pruritus
*Severe pruritus
*Evidence of self-trauma (loss, damage or staining of wool)
*Evidence of self-trauma (loss, damage or staining of wool)
*Inflammation with exudate followed by a yellow crust
*Inflammation with exudate followed by a yellow crust
*Weight loss or reduced weight gain in young stock
*Weight loss or reduced weight gain in young stock
*Secondary bacterial infection or Blowfly strike
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== Diagnosis ==
== Diagnosis ==
*History and clinical signs
*History and clinical signs
*Microscopic examination for mites (low magnification) to differentiate between Chorioptes and Psoroptes
*Skin scraping to microscopically identify mites (low magnification). Mites are found under scabs and in skin folds
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<br>'''Control'''
<br>'''Control'''
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*Economically important ectoparasite of sheep
*Causes pruritic condition of cattle
*Causes pruritic condition of cattle
=== Diagnosis ===
=== Diagnosis ===