selamectin and Toxocariasis

The efficacy of selamectin against experimentally induced and naturally acquired infections of adult ascarids (Toxocara cati) and adult hookworms (Ancylostoma tubaeforme) was evaluated in five controlled studies in cats. Two studies evaluated the efficacy of selamectin against both ascarid (natural or induced) and hookworm (induced) infections; two studies evaluated the efficacy of selamectin against single natural infections of T. cati or A. tubaeforme; and the fifth study evaluated the efficacy of selamectin against induced infections of A. tubaeforme. Cats received selamectin topically in unit doses designed to deliver a minimum of 6mgkg(-1). Treatments were applied to the skin on each animal's back at the base of the neck in front of the scapulae. For experimentally induced infections, cats were inoculated orally with approximately 500 embryonated eggs of T. cati 56 days prior to treatment and/or approximately 150-250 larvae (L(3)) of A. tubaeforme 30 or 42 days prior to treatment. For both induced and naturally acquired infections, cats were allocated randomly to treatments (6-12 cats per treatment) on the basis of fecal egg counts to receive either selamectin or a vehicle containing the inert formulation ingredients. In all studies, adult worm counts were performed at necropsy 14 days after the last treatment administration. Against T. cati, a single application of selamectin provided a 100% reduction in the geometric mean number of adult worms for both experimentally induced and naturally acquired infections. Against A. tubaeforme, a single administration of selamectin provided a 99.4% reduction in the geometric mean number of adult worms in cats with natural infections, and an 84.7-99.7% reduction in adult worms in cats with induced infections. Two doses of selamectin administered at monthly intervals provided a 91.9% reduction in the geometric mean number of adult A. tubaeforme worms in cats with experimentally induced infections. The geometric mean numbers of adult worms (T. cati and A. tubaeforme) from selamectin-treated cats were significantly (P< or =0.0018) lower than for vehicle-treated cats in all studies. Thus, a single topical unit dosage providing a minimum dosage of 6mgkg(-1) selamectin was highly effective in the treatment of naturally acquired and experimentally induced infections of T. cati and A. tubaeforme in cats.

Topics: Administration, Topical; Ancylostoma; Ancylostomiasis; Animals; Anthelmintics; Cat Diseases; Cats; Female; Italy; Ivermectin; Male; Toxocara; Toxocariasis; United States

The efficacy of selamectin against adult ascarids was evaluated in eight controlled and masked studies in dogs. Three laboratory studies evaluated selamectin against experimentally induced infections of Toxocara canis; three laboratory studies evaluated selamectin against naturally acquired infections of T. canis; one laboratory study evaluated selamectin against naturally acquired infections of both T. canis and Toxascaris leonina; one field study evaluated selamectin against naturally acquired infections of ascarids (T. canis and/or T. leonina) in dogs presented as veterinary patients. Selamectin was administered topically to the skin of dogs in unit doses designed to deliver a minimum of 6mgkg(-1) (range, 6-12mgkg(-1)). In all studies, dogs were allocated randomly to treatment assignments (selamectin or vehicle control in laboratory studies: selamectin or reference product in the field study) on the basis of pretreatment fecal egg counts. For induced infections, there were significant reductions in geometric mean numbers of adult T. canis after a single application of selamectin (93.9-98.1%, P=0.0001), after two monthly applications (> or =88.3%, P< or =0.0001), and after three monthly applications (100%, P< or =0.0002). In the natural infection laboratory studies, when selamectin was administered twice at an interval of 30 days, the percentage reductions in geometric mean numbers of adult T. canis at necropsy were 84.6, 91.3, and 97.9%, and when selamectin was administered on days 0, 14, and 30, the percentage reductions were 91.1 and 97.6%. Geometric mean fecal T. canis egg counts were reduced by > or =92.9% (P< or =0.0067) at the end of the studies. In the field study, geometric mean fecal ascarid egg counts were reduced by 89.5 and 95. 5% (P=0.0001) for 14 and 30 days, respectively, after a single treatment with selamectin, and by 94.0% (P=0.0001) 30 days after the second treatment with selamectin. These reductions compared favorably with the egg count reductions from dogs treated with a reference product containing praziquantel, pyrantel embonate, and febantel. There were no adverse drug experiences or treatment-related mortalities during any of the studies. Selamectin, when administered topically in a unit dose providing a minimum dosage of 6mgkg(-1), was safe and effective against adult T. canis and T. leonina and in reducing the fecal excretion of T. canis eggs in dogs.

Topics: Animals; Anthelmintics; Dog Diseases; Dogs; Europe; Ivermectin; Parasite Egg Count; Toxascariasis; Toxascaris; Toxocara canis; Toxocariasis; United States

The efficacy of selamectin in the treatment and prevention of naturally acquired Toxocara canis infections and experimentally induced flea (Ctenocephalides felis felis) infestations in dams and their suckling pups was evaluated by administering selamectin to the adult females only, approximately 40 and 10 days before parturition and 10 and 40 days after parturition. Unit doses of the commercial formulation of selamectin were administered to the dams to provide at least the minimum recommended dosage of 6mgkg(-1) (range, 6-12mgkg(-1)). Dams and their pups were housed in carpeted environments able to support the flea life cycle. Flea infestations were established initially by experimental infestation before treatment administration and by repeated re-infestation of dams at approximately weekly intervals throughout the study, which was completed 45 days after parturition. There were no adverse drug experiences related to treatment with selamectin and no treatment-related mortalities. Percentage reductions in geometric mean T. canis faecal egg counts for the selamectin-treated dams, compared with those receiving the negative-control treatment (vehicle only) were 99.7% at the end of the study (P=0.0001). Geometric mean faecal egg counts in pups from selamectin-treated females were reduced by > or =96% on the 24th and 34th days after birth (P=0.0001), and the number of adult worms recovered from the gastrointestinal tract of pups from selamectin-treated dams was reduced by 98.2% (P=0.0001), compared with that for pups from dams treated with the vehicle only. Percentage reductions in geometric mean flea counts for selamectin-treated dams and their pups, compared with vehicle-treated dams and their pups, were > or =99.8% (P=0.0001) and 100% (P=0.0001), respectively, throughout the study. Thus, selamectin administered topically at a minimum unit dosage of 6mgkg(-1) to dams with naturally acquired T. canis infections and experimentally induced C. felis infestations was safe and highly effective in the treatment, control, and prevention of adult T. canis infection and C. felis infestation affecting both the dams and their pups.

Topics: Administration, Topical; Animals; Anthelmintics; Antiparasitic Agents; Dog Diseases; Dogs; Ectoparasitic Infestations; Female; Housing, Animal; Ivermectin; Larva; Male; Parasite Egg Count; Pregnancy; Siphonaptera; Toxocara canis; Toxocariasis

The efficacy of a new spot-on formulation of selamectin plus sarolaner for cats was evaluated against induced infections with Ancylostoma tubaeforme (hookworm) and Toxocara cati (roundworm). Five laboratory studies were conducted using adult, purpose-bred cats. Four of the studies were designed to evaluate efficacy of the combination against A. tubaeforme, the dose-limiting gastrointestinal nematode species for selamectin. In two of these studies non-interference between selamectin and sarolaner was also evaluated. The fifth study evaluated efficacy of the combination against mixed infections of A. tubaeforme and T. cati. The hookworm isolates in three studies were of US origin, as was the roundworm isolate. In the two remaining studies, cats were inoculated with a hookworm isolate of European origin. Cats were inoculated with 150 (±50) to 200 (±50) infective hookworm larvae 30-42days prior to treatment and with 400 infective roundworm eggs 60days prior to treatment. Cats were ranked by pre-treatment faecal egg counts and randomly allocated to different treatment groups. In all studies, cats were treated at the minimum label dose to provide 6.0mg selamectin per kg bodyweight. All animals were euthanized 7-10days after treatment for worm counts. Efficacy was calculated based on the reduction of the geometric mean worm counts in the treated groups versus the placebo-treated control groups. The efficacy against adult hookworms was 99.2%, 94.3% and 100% in three of these studies, and was lower in the remaining two studies. The efficacy against T. cati was 100%. Furthermore, non-interference between sarolaner and selamectin was demonstrated. Thus, a single topical application of the new spot-on formulation of selamectin plus sarolaner at the minimum label dose is effective in the treatment of adult hookworm and roundworm infections in cats.

Topics: Ancylostoma; Ancylostomiasis; Animals; Antiparasitic Agents; Cat Diseases; Cats; Female; Isoxazoles; Ivermectin; Male; Random Allocation; Toxocara; Toxocariasis; Treatment Outcome