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Pediculosis (view source)

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*Pediculosis is an infestation of [[:Category:Lice|lice]]

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== Introduction ==

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Pediculosis is an infestation of [[:Category:Lice|lice]].

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Lice are host- specific, permanent parasites of animals, which are most prevalent in cooler conditions when the animals coat is longer.

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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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There are two types of lice; chewing and sucking lice. Chewing lice have rasping mouthparts and feed on skin scales. These appear in mammals and birds. Sucking lice only appear in mammals and have piercing mouthparts, which feed on blood and tissue fluids. In severe cases, pediculosis can cause anaemia([[Lice|sucking lice]]), weakness, discomfort and damage to hair or wool.

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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

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== Clinical Signs ==

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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 varibale degrees of pruritus caused by the mites.

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~~==Control==~~

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*Few insecticides will kill lice eggs on the ~~animal~~

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== Diagnosis ==

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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 by skin scrape, hair pluck or coat brushing, then identification of this sample under the microscope.

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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

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*Sucking lice are more susceptible to systemic insecticide treatment than chewing lice

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== Treatment and Control ==

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Few insecticides will kill lice eggs on the animal and '''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'''. Alternatively, a product with a '''two week residual activity''' can be used.

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Sucking lice are more susceptible to systemic insecticide treatment than chewing lice.

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== References ==

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Andrews, A.H, Blowey, R.W, Boyd, H and Eddy, R.G. (2004) Bovine Medicine (Second edition), Blackwell Publishing

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Blood, D.C. and Studdert, V. P. (1999) Saunders Comprehensive Veterinary Dictionary (2nd Edition) Elsevier Science

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Cowart, R.P. and Casteel, S.W. (2001) An Outline of Swine diseases: a handbook Wiley-Blackwell

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Foster, A, and Foll, C. (2003) BSAVA small animal dermatology (second edition) British Small Animal Veterinary Association

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

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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

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[[Category:Integumentary System - Parasitic Infections]]

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[[Category:To_Do_-~~_Clinical~~]]

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[[Category:To_Do_-_Review]]

Kthompson

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