Acta Veterinaria Scandinavica 2008, 50:1 http://www.actavetscand.com/content/50/1/1 Group 2 included 27 rabbits, all treated at the Animal Clinic Roslagstull, with bodyweights ranging from 1.6 to 6.5 kg and with a mean age of 4 years (range 6 months to 9.5 years). Twenty rabbits were intact males while the rest were four females and three castrated males. Most rabbits lived in single-rabbit households (n = 24) in this group as well, and the rest in households with two or more rabbits. All in-contact rabbits were treated in the multi-rabbit households. Treatment consisted of 3–6 ivermectin administrations at a 10 day interval. Initial subcutaneous injections at the first visit (mean dose of 1044 μgkg-1, range 618 to 2185) were followed by oral ivermectin, using the injectable formula (mean dose of 1324 μgkg-1, range 616–2732) twice and administered by the owner. Most rabbits (n = 23) were re-examined 30 days (range 28–35 days, one after 48 days) after the first visit. Depend- ing on the clinical signs at the second visit they were either given no more treatment (n = 2) or continued treatment. Twenty-one rabbits had a second injection, 14 of which had two additional oral ivermectin treatments repeated, with the same doses and interval as initially. Most of the latter were considered to still have clinical signs (n = 8) or to be mite positive after microscopic control (n = 1). Group 3 included 15 rabbits: one treated at the Gästrike Animal Clinic and 14 at the Animal Clinic Roslagstull. The mean age in this group was 2.2 years (range 3 months to 7 years) with bodyweights ranging from 1 to 7.4 kg. Eight rabbits were intact males while the rest were 5 females and 2 castrated males. Two rabbits belonged to multi-rabbit households. All in-contact rabbits were treated. Treatment consisted of administration of sela- mectin spot on topically at 1–3 occasions. The mean dose of selamectin used was 12.5 mgkg-1 (range 6.2 to 20.0). Assessment of response to therapy Clinical cure was assessed by re-examination or telephone contact with the owner. Treatment results were graded as in remission, relapse or treatment failure at the time of follow-up. Rabbits in remission were defined as having been free from clinical signs at re-examinations during the whole follow-up period. Relapses were defined as being free from clinical signs more than 3.5 months after treatment but showing signs again during the follow-up time. Treatment failures were cases that never cleared from clinical signs during the first 3.5 months or were recorded with relapse during this time. Adverse reactions of treatment were assessed by examination during revisit and by questioning the owner. Statistical analysis was made by using χ2 test [23]. Results Group 1: Ivermectin injections Nine rabbits out of 11 were classified as in remission at follow-up, whereas one was graded as treatment failure and one was recorded as relapse (table 1). Most of the rab- bits graded as in remission had no clinical signs (n = 5) or were mite negative (n = 1) as assessed by the veterinarian at revisit. The remaining three rabbits were reported free from clinical signs by telephone contact with the owner. The rabbit considered as a treatment failure was placed in a new cage during treatments. This rabbit had concurrent signs of conjunctivitis and dental problems; it died two months after the last treatment. One rabbit experienced a microscopically confirmed relapse two years after treat- ment and was re-treated. This rabbit had concurrent back pain. Shampoo containing bioallethrin and piperonylbu- toxid (Dermocan, Dogman) was advocated at the first occasion. In the remission group, three rabbits were recorded as having concurrent diseases (conjunctivitis, dental problems and back pain) and three were recorded as overweight. Four rabbits were concurrently bathed with sulphur shampoo (<5% sulphur) once or twice weekly in order to reduce the seborrhoea. Environmental treatment was conducted in three cases. One rabbit had its cage cleaned mechanically, one cage was cleaned with fipronil spray (2.5 mgml-1) (Frontline vet, Merial) and one with Dermocan-shampoo. Side effects (ataxia, resolving before the third injection) were reported in one rabbit. Although mite-negative at the last visit, this rabbit was found dead a few months after the last treatment. One rabbit experi- enced pain during injection of ivermectin. The follow-up time in this group ranged from 4 months to 3.5 years (mean time 18 months). Table 1: Treatment results of rabbits treated with ivermectin injections. Treatment results of rabbits treated with ivermectin injections at 11 day (range 9–21 days) intervals. Relative outcome (%) in brackets. No. of ivermectin injections Two Three Total In remission 5 (45.5) 4 (36.5) 9 (82.0) Treatment response (result) Failure 0 1 (9.0) 1 (9.0) Relapse 0 1 (9.0) 1 (9.0) Total 5 (45.5) 6 (54.5) 11(100) Page 3 of 6 (page number not for citation purposes)