Lice
Advocate®: Effective Against LiceInfestations with lice are common in mammals and birds, as well as many other animals. The mallophagean louse, Trichodectes canis, is feeds on skin dandruff and secretion from skin lesions. The anopluran louse, Linognathus setosus, is a capillary blood feeder. These lice suck blood frequently – about every couple of hours. The following section combines scientific information about biting and sucking lice. Additionally included are published data that led registration of Advocate under both the Australian and New Zealand Veterinary Medicines Authority s well as to the registration of Advocate against Biting Lice in Europe in August 2007. Herewith we declare our intention to provide the Veterinary Profession with utmost current knowledge, however, with the advisement that the use of the product must adhere to the marketing authorisations for each individual country. The ParasiteIn dogs, two species of lice have been reported: one an anoplura species – the blood sucking louse Linognathus setosus (Olfers, 1816), and the other a mallophagan species – the chewing or biting louse Trichodectes canis (deGeer, 1778). In general, lice are reported to be common ectoparasites of dogs in regions of the northern hemisphere. Trichodectes canis is about 1.5 mm in length and dorsoventrally flattened. It is yellow-brownish in colour and the most distinguishable characteristic is that the head is rectangular, wider than it is long and has a blunt ending. The abdomen is broad and oval in shape.
In contrast, the most distinguishable signs of the sucking louse, Linognathus setosus, are the piercing mouthparts and a head that is smaller than the thorax. The abdomen is wide and egg-shaped. The size of Linognathus is about 1.7 mm and it is brown-white in colour. Cats may be infested with Felicola subrostratus (Burmeister, 1838), a mallophagan louse; anoplura lice have not been recorded in cats. Life CycleTrichodectes canis
Pathogenesis and Clinical AppearanceLice are transmitted mainly by host to host interaction, either directly or from contact with shared materials, e.g. bedding or lice comb. Off the host, lice survive only for a limited period of time. The mallophagean louse, Trichodectes canis, is feeds on skin dandruff and secretion from skin lesions. Heavy infestations may cause eczema with crusts and alopecia. Constant pruritus is caused by the wandering lice. The anopluran louse, Linognathus setosus, is a capillary blood feeder. These lice suck blood frequently – about every couple of hours. In heavy infestations, lesions of the skin with excoriation, urticaria-like lesions with alopecia, and even necrotic skin lesions are all typical clinical signs of infestation with the sucking louse. Infested dogs are restless and display constant pruritus, with risk of secondary dermal infections. Zoonotic significanceBecause lice are host-specific, the lice of dogs and cats will not persist on man for more than a few hours. However, they can be a source of irritation when present. Linognathus setosus has been reported as a vector of the dog tapeworm Dipylidium caninum, although it is far less important as a vector than the flea. DiagnosisInfestation with lice is visible to the naked eye due to the relatively large size of the adult louse stage and the eggs. To facilitate the examination, especially with mild infestations, combing should be performed. From hair that is combed off the animal, the typical individual louse egg glued to the hair shaft can be identified. For species specification, microscopic examination with low magnitude is recommended. Efficacy of Advocate®In a clinical field study, imidacloprid (Advantage) was tested in dogs with natural infestation of both sucking and chewing lice1. Dogs that tested positive with lice were treated using 10% imidacloprid spot-on at a dosage of 10 mg/ kg b. w. The study included 27 dogs from a large variety of breeds, with light (13 dogs), moderate (8 dogs) or high (6 dogs) louse infestations. In addition to the parasitological examinations, dermatological lesions were examined at 24 hours and 2, 4 and 6 weeks after treatment. Imidacloprid provided a very high level of efficacy, with a 24-hour post treatment knock-down effect. All dogs were free of lice for up to 6 weeks following treatment. A registered claim for the treatment of both biting and sucking lice exists in Australia for Advantage. The performance of Advocate against sucking lice would be expected to be identical, as there is no variation in the concentration or dosage of imidacloprid between these two formulations. European studies demonstrate that Advocate offers a high level of lice control. A marked reduction of 89.9% one day after treatment and an overall efficacy of 99.7% at day 28 has been proven.2 The success of a single treatment in the strong indication in slowly developing biting lice shows the plausibility of long-term efficacy of Advocate.2
New in 2007: Registration for EuropeSince August 2007, Advocate is now also registered in Europe for the treatment against biting lice (Trichodectes canis) on dogs.
Questions about the product?If you have any questions about the product, please contact our Veterinary Service. References
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Animations for Download
Gripping life cycle animations of this parasite you'll find in the download area. |
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Last changed: 19.11.2008 | ||||||||
