Difference between revisions of "Psoroptic Mange"

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== Synonyms  ==
+
{{OpenPagesTop}}
 
+
Also Known as: '''''Sheep Scab Psoroptic Scabies — Psoroptosis'''''
*Sheep Scab  
 
*Psoroptic scabies
 
*Psoroptosis<br>
 
  
 
== 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.
 
 
 
'''Description''': The mite looks very similar in appearance to Chorioptes,&nbsp;being oval&nbsp;in&nbsp;shape with long legs,&nbsp;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.&nbsp;This life cycle takes around 10 days to complete.&nbsp;Adult female life expectancy is around&nbsp;one month&nbsp;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.
+
Other species of Psoroptes mite affect a variety of species including cattle, goats, horse, rabbit, camelid, however, all mites are host specific.  
 
 
'''Predilection site''': Lesions are&nbsp;most common on flanks, neck, back and shoulders
 
 
 
This mite is found worldwide, but has been eradicated from Australia and New Zealand.  
 
 
 
<br>
 
  
 
== Pathogenesis  ==
 
== Pathogenesis  ==
  
The mite is active in the keratin layer of the skin and has abrasive mouthparts. It&nbsp;feeds on exudate of lymph, skin cells and bacteria caused by a hypersensitivity reaction to antigenic mite faeces,&nbsp;by the host. This causes intense&nbsp;pruritus, 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 - Introduction|hypersensitivity reaction]] to antigenic mite faeces by the host. This causes '''intense pruritus''', leading to self trauma, crust and scale formation and inflammation.  
 
 
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, as the blowflies find the damaged skin ideal for egg laying.
 
  
The disease is most prevalent in autumn and&nbsp;winter months, however does still occur in the summer, especially in sheep that have not been shorn.  
+
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.  
  
Psoroptic mange in sheep '''used to be&nbsp;a ''''''notifiable disease '''in the UK, but has been de-regulated since 1992
+
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.
  
== Clinical signs  ==
+
Psoroptic mange in sheep '''used to be a notifiable ''''''disease '''in the UK, but has been de-regulated since 1992.
  
*Severe pruritus
+
== Clinical Signs  ==
*Evidence of self-trauma (loss, damage or staining of wool)
 
*Inflammation with exudate followed by a yellow crust
 
*Weight loss or reduced weight gain in young stock
 
*Secondary bacterial infection or Blowfly strike
 
  
<br>
+
'''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.
  
 
== Diagnosis  ==
 
== Diagnosis  ==
  
*History and clinical signs  
+
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.
*Skin scraping to microscopically identify mites (low magnification). Mites are found under scabs and in skin folds
 
 
 
<br>
 
  
 
== Treatment/ Control  ==
 
== Treatment/ Control  ==
  
Infestations are difficult to eliminate from a&nbsp;flock so a key factor in control is to not allow it to enter.
+
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.  
 
 
*New stock should be isolated for at least three weeks before mixing with the main flock  
 
*Plunge dipping is curative and preventative<br>- dip must contain the Organophosphate diazinon or the Synthetic Pyrethroid cis-cypermethrin<br>- plunge dipping must last for at least one minute and the head should be fully submerged twice during this time<br>- the sheep must be kept moving when in the dip as the movement displaces air from in the fleece allwing better penetration
 
*Can treat with avermectins or milbemycins by injection<br>- only moxidectin has any prophylactic effect<br>- need two&nbsp;injections 7 days apart or one single dose (doramectin only)&nbsp;<br>
 
 
 
== Other species<br> ==
 
 
 
'''Cattle'''
 
 
 
Uncommon in the UK.
 
 
 
Affects withers mainly
 
 
 
Can be treated with avermectin, milbemycins or topical acaracides
 
  
&nbsp;
+
*'''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
  
'''Horse'''
+
''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>
  
Notifiable in the UK, but has not been recorded for many years
+
== Other species ==
  
No licensed product for treatment of&nbsp;horses in the UK
+
'''Cattle''' 
  
&nbsp;
+
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.
  
'''Rabbits'''
+
'''Horses'''  
  
'Ear canker mite' in rabbits
+
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.
  
Externam auditory canal infection is often asymptomatic, but may cause scratching and head shaking behaviour
+
'''Rabbits'''
  
Can be treated with avermectin, milbemycins or topical acaracides
+
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]].
  
&nbsp;
 
  
&nbsp;
+
{{Chapter}}
 +
{{Mansonchapter
 +
|chapterlink = http://www.mansonpublishing.co.uk/book-images/9781840760491_sample.pdf
 +
|chaptername = Sheep Scab
 +
|book = Sheep Medicine
 +
|author = Philip R. Scott
 +
|isbn = 9781840761498
 +
}}
  
== References ==
+
== References ==
  
Aitken, I.D, (2007) Diseases of Sheep fourth edition, Blackwell Publishing
+
Aitken, I.D, (2007) '''Diseases of Sheep fourth edition,''''' Blackwell Publishing ''
  
Fox, M and Jacobs, D. (2007) Parasitology Study Guide Part 1: Ectoparasites, Royal Veterinary College  
+
Fox, M and Jacobs, D. (2007) '''Parasitology Study Guide Part 1: Ectoparasites,''''' Royal Veterinary College ''
  
Hindson, J.C, (2002) Manual of Sheep Diseases second edition, Blackwell Publishing
+
Hindson, J.C, (2002)''' Manual of Sheep Diseases second edition,''''' Blackwell Publishing ''
  
Taylor, M.A, Coop, R.L, Wall, R.L, (2007) Veterinary Parasitology third edition, Blackwell Publishing
+
Taylor, M.A, Coop, R.L, Wall, R.L, (2007) '''Veterinary Parasitology third edition,''''' Blackwell Publishing ''
  
  
 +
{{review}}
  
&nbsp;
+
{{OpenPages}}
  
[[Category:To_Do_-_Kate]] [[Category:Integumentary_System_-_Mite_Infections]]
+
[[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]]

Latest revision as of 21:28, 26 September 2012


Also Known as: Sheep Scab — Psoroptic Scabies — Psoroptosis

Introduction

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.

Pathogenesis

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.

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, as the blowflies find the damaged skin ideal for egg laying.

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.

Psoroptic mange in sheep 'used to be a notifiable 'disease in the UK, but has been de-regulated since 1992.

Clinical Signs

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.

Diagnosis

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.

Treatment/ Control

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.

  • 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

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. 

Other species

Cattle

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.

Horses

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.

Rabbits

Rabbits become infected by Psoroptes cuniculi causing '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 rabbit section.



Sample Book Chapters
Publisher
Free chapter
Book
Authors
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Sheep Scab
Sheep Medicine
Philip R. Scott
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References

Aitken, I.D, (2007) Diseases of Sheep fourth edition, Blackwell Publishing

Fox, M and Jacobs, D. (2007) Parasitology Study Guide Part 1: Ectoparasites, Royal Veterinary College

Hindson, J.C, (2002) Manual of Sheep Diseases second edition, Blackwell Publishing

Taylor, M.A, Coop, R.L, Wall, R.L, (2007) Veterinary Parasitology third edition, Blackwell Publishing




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