Acta Veterinaria Scandinavica 2008, 50:1 http://www.actavetscand.com/content/50/1/1 without feeding in cool temperatures [2,3]. Eggs that fall off the host can be a source of re-infestation. Cheyletiellosis is a zoonosis, causing papular, pruritic der- matitis in humans [1,2]. Experimental studies transferring C. yasguri between dogs and rabbits suggest a low host specificity of the mite [1]. Cheyletiellosis in the rabbit is common and clinical signs consist of varying degrees of pruritus, alopecia, dry to oily seborrhoea with crusts and sometimes erythema (figure 1) [1]. Lesions mainly affect the withers but sometimes extend to the back and ventral abdomen. In some cases lesions are seen only in the face. The severity of clinical signs ranges from asymptomatic to moderate, although widespread lesions can be seen in immunocompromised rabbits [1-3]. Diagnosis of Cheyletiella infestation is made by demon- stration of the mite or eggs in superficial skin scrapings, transparent tape preparations or by flea combing. A variety of antiparasitic treatment protocols have been successfully used for ectoparasitic mite infestation in small animal veterinary practice. In the literature there is evidence of efficacy using fipronil [3,4], ivermectin [5-8] and selamectin [9,10] in the treatment of cheyletiellosis in the dog and cat. Use of ectoparasiticides in the rabbit has been reported in the treatment of Psoroptes cuniculi and Sarcoptes scabei with ivermectin [11-13], ivermectin and fipronil combination [14], moxidectin [15], eprinomec- tin [16], selamectin [17,18] and doramectin [19]. Although ivermectin, selamectin and moxidectin have been advocated for treatment of cheyletiellosis in rabbits in textbooks and proceedings [2,20,21], no studies to our RFaigbubritew1ith cheyletiellosis Rabbit with cheyletiellosis. Rabbit with cheyletiellosis, with typical signs of seborrhoea and scaling over the withers and back. knowledge, have been published to support the recom- mendation. In the view of evidence-based medicine, it is important that primary references are available to sub- stantiate textbook statement and clinical practice. The objective of the present study was therefore to evaluate the efficacy and safety of selamectin and ivermectin in the treatment of Cheyletiella mite infestation in rabbits in clin- ical practice. Methods Study design and inclusion criteria Totally 282 medical records of rabbits from two veterinary settings (Gästrike Animal Clinic, Sandviken, Sweden, and Animal Clinic Roslagstull, Stockholm, Sweden) were reviewed. Of these, 53 rabbits were included in the study. Prerequisites for selection were that clinical signs compat- ible with Cheyletiella infestation were verified by a demon- stration of Cheyletiella mites through light microscopy examination of skin scrapings, material from flea comb- ing or transparent tape preparations under 4 or 10 × 100 magnifications. Furthermore, the rabbits should have been treated with ivermectin or selamectin and a follow- up should be possible through telephone contact with the owner or through a revisit at the clinic. The following information was collected from the two veterinary set- tings: descriptions including age, sex, weight, clinical signs, diagnose verification, treatment protocol (sub- stance, dose, route of administration and interval), number of rabbits in the household, other treatments and evidence of concurrent diseases. A record of overweight was made if the rabbit's weight was more than 20% above the recommended maximum weight of the breed accord- ing to the Nordic rabbit standard [22]. The rabbits were divided into three treatment groups, iver- mectin (Ivomec®vet. injectable, 10 mg/ml, Merial SAS, Lyon) injections (Group 1), combination of injections and oral administration of ivermectin (Ivomec®vet. inject- able, 10 mg/ml, Merial SAS, Lyon) (Group 2) and topical selamectin (Stronghold®/Revolution, 60 mg/ml, Pfizer Inc., New York) (Group 3). Treatment groups Group 1 included 11 rabbits, all treated at the Gästrike Animal Clinic, with a mean age of 4.4 years (range 9 months to 7 years) with bodyweights ranging from 1.4 to 4.6 kg. Eight rabbits were male and three female. Most of the rabbits (n = 9) were from single-rabbit households. In the two multi-rabbit households, all in-contact rabbits were treated. The rabbits were treated with ivermectin injections subcutaneously at two (n = 5) or three (n = 6) occasions. The mean dose was 253 μg kg-1 (range 200– 476) and the mean injection interval was 11 days (range 9–21). Page 2 of 6 (page number not for citation purposes)