Difference between revisions of "Pediculosis"

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*Pediculosis is an infestation of [[:Category:Lice|lice]]
== Introduction ==
 
Pediculosis is an infestation of [[:Category:Lice|lice]]. Lice are host-specific, permanent parasites of animals, which are most prevalent in cooler conditions when the animals coat is longer.
 
  
Lice are mostly spread by direct contact, as they can only survive off the host for up to one week. The eggs of lice are found on the host 'cemented' to the hair and the whole lifecycle takes around 2- 3 weeks to complete.
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*Infestation is called '''pediculosis'''
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*May cause anaemia ([[Lice|sucking lice]]), weakness, discomfort and damage to hair or wool
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*More common in low temperatures when hair is longer
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*Host-specific
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*Spread by direct contact
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*Most lesions are due to self-inflicted trauma
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*Grossly:
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**Papules, crusts, secondary excoriations
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**Eggs and lice visible in lesions
  
There are two types of lice; [[:Category:Chewing Lice|chewing]] and [[:Category:Sucking Lice|sucking]] lice. In severe cases, pediculosis can cause [[:Category:Anaemia|anaemia]] (sucking lice), weakness, discomfort and damage to hair or wool.
 
  
== Clinical Signs ==
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==Control==
Clinical signs are species specific to some extent, but all usually include self-trauma causing hair loss and abrasions on the skin, which is due to variable degrees of pruritus caused by the lice.
 
  
Discomfort and pruritus may also interfere with normal feeding, causing weight loss and anorexia. This may also exacerbate any existing lameness.
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*Few insecticides will kill lice eggs on the animal
  
Severe cases occasionally may cause [[Anaemia|anaemia]].
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*'''Two treatments''' are needed to kill nymphs emerging from eggs at the time of the initial treatment and those that will emerge 2-3 weeks later
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**At '''two week intervals'''
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**Or a product with a '''two week residual activity''' can be used
  
== Diagnosis ==
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*Sucking lice are more susceptible to systemic insecticide treatment than chewing lice
Clinical signs and history, such as indoor housing for farm animals can be indicative of the disease.
 
  
Definitive diagnosis can be achieved by identification of the lice and eggs in skin scrape, hair pluck or coat brushing sample under the microscope.
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*Resistance to insecticides may become a problem so alternating the chemicals used and avoiding pour on treatments (which have a greater risk of resistance developing) should be considered
  
== Treatment and Control ==
 
Few [[Ectoparasiticides|insecticides]] will kill lice eggs on the animal therefore '''two treatments at two week intervals''' are needed to kill nymphs emerging from eggs at the time of the initial treatment and those that will emerge 2-3 weeks later. Alternatively, a product with a '''two week residual activity''' can be used.
 
  
Sucking lice are more susceptible to systemic insecticide treatment than chewing lice.
 
  
Pour-on and injectable formulations are available.
 
  
{{Learning
 
|flashcards = [[Lice_Flashcards|Lice Flashcards]]
 
  
[[Cattle Medicine Q&A 09]]
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[[Category:To_Do_-_Clinical]]
}}
 
 
 
== References ==
 
Andrews, A.H, Blowey, R.W, Boyd, H and Eddy, R.G. (2004) '''Bovine Medicine''' (Second edition), ''Blackwell Publishing''
 
 
Blood, D.C. and Studdert, V. P. (1999) '''Saunders Comprehensive Veterinary Dictionary''' (2nd Edition), ''Elsevier Science''
 
 
 
Cowart, R.P. and Casteel, S.W. (2001) '''An Outline of Swine diseases: a handbook''', ''Wiley-Blackwell''
 
 
 
Foster, A, and Foll, C. (2003) '''BSAVA small animal dermatology''' (second edition), ''British Small Animal Veterinary Association''
 
 
 
Fox, M and Jacobs, D. (2007) '''Parasitology Study Guide Part 1: Ectoparasites''', Royal Veterinary College
 
 
 
 
 
{{review}}
 
 
 
{{OpenPages}}
 
 
 
[[Category:Integumentary System - Parasitic Infections]]
 
[[Category:Expert_Review]]
 

Revision as of 15:52, 29 July 2010

  • Pediculosis is an infestation of lice
  • Infestation is called pediculosis
  • May cause anaemia (sucking lice), weakness, discomfort and damage to hair or wool
  • More common in low temperatures when hair is longer
  • Host-specific
  • Spread by direct contact
  • Most lesions are due to self-inflicted trauma
  • Grossly:
    • Papules, crusts, secondary excoriations
    • Eggs and lice visible in lesions


Control

  • Few insecticides will kill lice eggs on the animal
  • Two treatments are needed to kill nymphs emerging from eggs at the time of the initial treatment and those that will emerge 2-3 weeks later
    • At two week intervals
    • Or a product with a two week residual activity can be used
  • Sucking lice are more susceptible to systemic insecticide treatment than chewing lice
  • Resistance to insecticides may become a problem so alternating the chemicals used and avoiding pour on treatments (which have a greater risk of resistance developing) should be considered