Evaluation of spinosad for the oral treatment and control of flea infestations on cats in Europe.

METHODS: An ectoparasiticide containing spinosad was evaluated as an oral formulation for cats. Two European laboratory studies and a European multicentre field efficacy and safety study assessed the use of a chewable tablet formulation of spinosad at a dose range of 50-75 mg/kg for treatment and control of flea infestations on cats. RESULTS: The studies with experimentally infested cats consistently demonstrated persistent activity against Ctenocephalides felis with >98 per cent efficacy at four weeks post-treatment. In the field study with naturally infested client-owned cats from 18 clinics across Germany and Italy, two monthly doses of spinosad were administered; selamectin was the comparator product. Safety was evaluated in 226 cats, each receiving at least one dose of spinosad or selamectin; both products were well tolerated. 113 spinosad-treated cats and 71 selamectin-treated cats showed >97 per cent reductions in geometric mean flea counts within 14 days post-treatment and at 60 days post-treatment efficacy was >98 per cent in both groups. Analysis of success rates showed 96 per cent in spinosad-treated cats compared with 90.9 per cent in selamectin-treated cats at day 60. The spinosad tablets were successfully administered to over 98 percent of cats. These studies indicate that this formulation of spinosad is safe and efficacious for treatment and prevention of flea infestations in cats.

Outcome of an artificial coccidial infection in poults under the influence of floor heating.

Coccidiosis is one of the most prevalent diseases in poultry. The objective of the current study was to determine the effects of floor heating when poults were artificially infected with Eimeria regarding the outcome of the infection and secondary effects on litter quality and health of the foot pad. Two trials were performed. In each trial, 4 groups of 2-wk-old turkeys were reared for a 4-wk period. All birds were fed ad libitum identical pelleted diets without any anticoccidial additive. The first 2 groups were housed on dry wood shavings, with and without floor heating; the other 2 groups were housed on wet wood shavings (35% moisture, achieved by adding water as required), with and without floor heating. Two birds only (primary seeder birds; the other 18 birds were nominated as secondary infected birds) in each of the 4 groups were experimentally infected orally with Eimeria adenoeides (~50,000 oocysts/bird). The number of oocysts eliminated via excreta was determined repeatedly. On d 42, each bird not only was scored macroscopically for coccidial lesions in the cecum but also oocyst counts were determined in the cecal contents. Finally, the foot pads were assessed weekly for external scoring and on d 42 of life for histopathological scoring. Although the counts of oocysts in seeder birds were almost identical (d 6 postinoculation), oocyst counts in excreta of secondary birds were markedly reduced in both trials when the poults were not exposed to wet litter. Moreover, in both trials using floor heating with exposure to wet litter resulted in a higher oocyst count in the excreta of secondary infected birds (3.72/3.92 in trials 1 and 2) on d 24 postinoculation compared with the other groups. Using floor heating resulted in significantly decreased foot pad dermatitis scores compared with groups housed without floor heating. In conclusion, the differences in oocyst counts indicate that the process of sporulation is affected by both the moisture and the temperature of the litter.

Foot-pad dermatitis and experimentally induced coccidiosis in young turkeys fed a diet without anticoccidia.

Foot-pad dermatitis (FPD) is a widespread challenge to turkey production. This study aimed at evaluating the effects of using floor heating and exposure to litter with critical moisture content (35%) under experimental infection with Eimeria. adenoeides on the severity of FPD in turkeys. Two trials were done; in each trial, 4 groups of 2-wk-old female turkeys were reared over 4 wk. At the start of the experiment (d 14), each bird had normal foot pads. All birds were fed ad libitum on identical pelleted diets without any anticoccidial additive. The first 2 groups were kept on dry wood shavings with or without floor heating; the other 2 groups were housed on wet wood shavings of 35% moisture with or without floor heating. Two birds in each of the 4 groups were experimentally infected with E. adenoeides via crop intubation (~50,000 oocysts/bird). Foot pads were assessed weekly for external scoring and at d 42 of life for histopathological scoring. The number of oocysts eliminated via excreta was determined. In both trials, using floor heating resulted in significantly decreased FPD scores (2.06 ± 0.735; 1.47 ± 0.734, trials 1 and 2, respectively) compared with groups housed without floor heating (3.88 ± 0.812; 2.73 ± 1.25, trials 1 and 2, respectively). Birds continuously exposed to wet litter (35% moisture) showed significantly increased FPD scores (3.41 ± 1.23; 2.69 ± 1.34, trials 1 and 2, respectively) compared with the group not exposed to wet litter (2.53 ± 1.00; 1.53 ± 0.683, trials 1 and 2, respectively). The coccidial infection in both trials resulted in markedly lowered DM contents of excreta (14.8 and 15.1%, trials 1 and 2, respectively) and litter (58.0 and 57.6%, trials 1 and 2, respectively) in the groups exposed to wet litter without using floor heating. In both trials, using floor heating resulted in the highest mean DM content of litter (85.1 and 85.0%, trials 1 and 2, respectively) and the highest BW (2,693 and 2,559 g, trials 1 and 2, respectively). The results suggest that induced diarrhea caused by coccidial infection led to poor litter quality, and hence, increased the severity of FPD, which can be overcome by using floor heating.

Evaluation of spinosad for the oral treatment and control of flea infestations on dogs in Europe.

The novel ectoparasiticide spinosad is a naturally occurring mixture of spinosyns A and D formed during a fermentation process. The spinosyns are tetracyclic macrolides with a unique ring system. Their mode of action differs from that of other commercially available insecticides. Laboratory and field trials were conducted to evaluate the use of spinosad in a chewable tablet at a dose range of 45 to 70 mg/kg for the treatment and control of flea infestations on dogs in Europe. Laboratory studies with artificially infested dogs confirmed persistent activity against Ctenocephalides felis of higher than 99 per cent at three weeks post-treatment with values of 96.5 to 97.8 per cent at four weeks. Two multicentric field trials with naturally infected client-owned animals in five European countries used selamectin as comparator. Monthly doses were given during the summer when many homes were heavily infested. Households with spinosad-treated dogs showed cumulative benefits with flea burdens reduced by about 97 per cent at 14 and 30 days and by 99.6 per cent at 60 and 90 days. Corresponding figures for selamectin were significantly lower (P<0.05) at all time points: between 88.5 and 91 per cent at 14 and 30 days, then 97.8 and 98.2 per cent at 60 and 90 days. Thus, the performance of spinosad compared favourably with that of the established reference product.

The effect of nematode administration on canine atopic dermatitis.

Canine atopic dermatitis is a common disease and is considered as an animal model of the human disease. Immunomodulation by helminths is reported in several species. The aim of this study was to determine whether nematodes have an immunomodulatory effect on atopic dermatitis in dogs. In the pilot study, 12 atopic dogs were infected with either embryonated eggs of Trichuris vulpis (500 and 2500 eggs in 3 dogs each) or L3 larvae of Uncinaria stenocephala (100, 500 and 2500 eggs in 2 dogs each), respectively, for 3 months. Pruritus was evaluated with visual analogue scales and clinical lesions with the canine atopic dermatitis extent and severity index (CADESI). Skin biopsies were obtained for histopathology at the beginning and end of the study. In the subsequent placebo-controlled, double-blinded, randomised study, 21 dogs received either 2500 embryonated T. vulpis eggs or placebo and were evaluated similarly. In addition, allergen-specific serum IgE concentrations were determined. All dogs in the pilot study improved in their lesion scores, most in their pruritus scores. The cutaneous inflammatory infiltrate did not change significantly. In the subsequent randomised study, there was no significant difference between placebo and Trichuris administration in regard to pruritus or CADESI. IgE concentrations also did not change significantly. Infection with T. vulpis did not significantly change clinical signs of canine atopic dermatitis.

Comparative efficacy of imidacloprid, selamectin, fipronil-(S)-methoprene, and metaflumizone against cats experimentally infested with Ctenocephalides felis.

Four active ingredients--imidacloprid selamectin, fipronil-(S)-methoprene, and metaflumizone--were tested to assess the speed of flea kill against existing flea infestations and subsequent reinfestations. Thirty flea-infested cats were allocated to four treatment groups and one untreated control group. Flea counts were performed 6, 18, and 48 hours after treatment (day 0) and 2, 4, and 24 hours after weekly flea reinfestations. Cats were also reinfested with fleas after the 6- and 18-hour counts on day 0 and after the 2- and 4-hour counts on subsequent count days. Imidacloprid provided significantly greater flea kill at diverse time points. At the 24-hour counts, all compounds showed expected and similar high efficacies. On study day 34, imidacloprid showed the highest efficacy at 24 hours after reinfestation, with 90.8% flea reduction compared with 55.7% to 67.4% in the other treatment groups. A single topical application of imidacloprid provided a high efficacy in the early elimination of adult fleas, limiting the risk of pathogen transmission and flea allergy dermatitis.