Comparative speed of kill of selamectin, imidacloprid, and fipronil-(S)-methoprene spot-on formulations against fleas on cats

The speed of kill of selamectin, imidacloprid, and fipronil-(S)-methoprene against Ctenocephalides felis infestations on cats for one month following a single treatment was evaluated. Eighty cats were randomly allocated so that there were 20 cats in four different treatment groups. On Days -2, 7, 14, 21, and 28, each cat was infested with 100 adult C. felis from the Kansas 1 flea strain. Following initial application only imidacloprid had caused a significant reduction in adult fleas on treated cats within 6 hours, but by 24 hours all three formulations had killed 96.7% of the fleas. At 7 days post treatment, all three formulations reduced flea populations within 6 and 24 hours by 68.4% and 99.4%, respectively. At 21 and 28 days after treatment, none of the formulations killed significant numbers of fleas as compared to controls within 6 hours of infestation. At 28 days after treatment, selamectin, fipronil-(S)-methoprene, and imidacloprid had killed 99.0%, 86.4%, and 72.6% of the fleas within 48 hours of infestation, respectively. This study demonstrates that the speed of kill of residual flea products on cats decreases throughout the month following application. It also demonstrated that selamectin provided the highest level of residual activity on cats against the Kansas 1 flea strain.     

Efficacy of fipronil-(S)-methoprene on fleas, flea egg collection, and flea egg development following transplantation of gravid fleas onto treated cats

The goal of this study was to assess the insect growth regulator activity of the combination product fipronil-(S)-methoprene under a severe challenge model. Gravid fleas were allowed to feed on untreated donor cats for 48 hours before being transplanted onto untreated control cats and treated cats (treated once on day 0); 24 hours later, adult fleas were collected from all cats and counted to assess the 24-hour kill efficacy against the transplanted fleas, and flea eggs were collected and incubated to assess viability. The process was repeated weekly for 11 weeks. The 24-hour efficacy against transplanted adult fleas in the treated group was about 100% for the first 3 weeks and gradually declined to 93.4% by week 6. Egg production numbers were reduced on the treated cats compared with controls, with geometric mean egg counts on treated cats reduced from 76.9% to 96.3% during the initial 6 weeks of the study. The combination product was 100% ovicidal through day 56 and was still about 98% effective against eggs at the end of the study (day 76).     

Efficacy of selamectin and fipronil-(S)-methoprene spot-on formulations applied to cats against adult cat fleas (Ctenocephalides felis), flea eggs, and adult flea emergence

A study was conducted to evaluate the efficacy of selamectin and fipronil-(S)-methoprene against adult cat fleas (Ctenocephalides felis), flea egg production, and the viability of flea eggs collected from treated cats. Cats were infested with approximately 50 adult fleas 2 days before treatment and weekly thereafter; flea eggs were collected and counted on days 0, 1, 2, and 3 and 48 and 72 hours after each weekly flea infestation. Live fleas were collected approximately 72 hours after treatment or infestation. Compared with fipronil-(S)-methoprene, selamectin provided significantly greater control of adult fleas from days 24 to 31 and significantly greater reduction in egg production from days 16 to 45. For the most part, both products significantly impacted larval and adult emergence for the entire 6-week study, with fipronil-(S)-methoprene providing significantly greater reduction in larval and adult emergence at week 6.     

Efficacy of a topically applied spot-on formulation of a novel insecticide, metaflumizone, applied to cats against a flea strain (KS1) with documented reduced susceptibility to various insecticides

A spot-on metaflumizone formulation was evaluated in adult domestic short hair cats to determine its adultidical efficacy against a flea strain that has reduced susceptibility to a number of insecticides. Eight cats served as non-treated controls, eight cats were treated with a metaflumizone formulation at 0.2 ml/kg (40 mg metaflumizone/kg) and eight cats were treated with fipronil 10% w/v-(s)-methoprene 12%w/v at 0.075 ml/kg (7.5-7.7 mg fipronil/kg:9.0-9.2 mg (s)-methoprene/kg). On days -1, 7, 14, 21, 28, 35, and 42 each cat was infested with approximately 100 unfed KS1 cat fleas, Ctenocephalides felis. At approximately 48 h after treatment or infestation, each cat was combed to remove and count live fleas. Treatment with metaflumizone provided > or = 99.3% efficacy for 3 weeks post-treatment and then 97.4, 91.4 and 86.2% efficacy at 4, 5 and 6 weeks post-treatment, respectively. Fipronil-(s)-methoprene provided 99.6% efficacy at 1 week post-treatment and then 97.6, 96.4, 71.3, 22.0 and 13.1% efficacy at weeks 2, 3, 4, 5 and 6, respectively. The reductions in flea numbers were significantly greater for the metaflumizone treatment than for fipronil-(s)-methoprene from 3 to 6 weeks after treatment.     

Efficacy of a topically applied formulation of metaflumizone on cats against the adult cat flea, flea egg production and hatch, and adult flea emergence

A spot-on metaflumizone formulation was evaluated to determine its adulticidal efficacy, effect upon egg production, and ovicidal activity when applied to flea infested cats. Eight male and eight female adult domestic shorthair cats were randomly assigned to either serve as non-treated controls or were treated topically with a minimum of 40mg/kg metaflumizone in single spot-on Day 0. On Days -2, 7, 14, 21, 28, 35, 42, 49, and 56, each cat was infested with approximately 100 unfed cat fleas, Ctenocephalides felis felis. On Days 1, 2, and 3, and at 48 and 72h after each post-treatment reinfestation, flea eggs were collected and counted. At approximately 72h after treatment or infestation, each cat was combed to remove and count live fleas. Egg viability was determined by examining hatched eggs after 5 days and adult emergence was determined 28 days after egg collection. Metaflumizone provided >/=99.6% efficacy against adult fleas from Days 3 to 45 following a single application. Following treatment, egg production fell by 51.6% within 24h and 99.2% within 48h. Following subsequent weekly infestations egg production from treated cats was negligible out to Day 38, with >/=99.5% reduction relative to non-treated cats. Where there were eggs to evaluate, metaflumizone treatment did not have any apparent effect on the hatching of eggs or on the development and emergence of adult fleas from the eggs produced by fleas from treated animals.     

Efficacy of a novel formulation of metaflumizone for the control of fleas (Ctenocephalides felis) on cats

A novel spot-on formulation containing metaflumizone (ProMeris for Cats, Fort Dodge Animal Health, Overland Park, KS) was evaluated in five laboratory studies to determine the duration of residual efficacy in cats against fleas after a single spot treatment. In each study, eight domestic shorthair cats were randomly allocated to each treatment group and individually housed. One group in each study remained non-treated. In one study, an additional group of eight cats was treated with a placebo formulation. Cats were treated topically with metaflumizone formulation to provide a dose of at least 40mg metaflumizone/kg. Cats were infested with 100 cat fleas (Ctenocephalides felis felis) once per week for approximately 8 weeks. Cats were comb counted 48h after treatment and each infestation to determine the number of viable fleas present. There were no significant differences in flea counts between the non-treated control and the placebo-treated control (P>0.05) other than a 26% reduction at week 1, demonstrating that the formulation excipients had no activity. Metaflumizone treatment resulted in significantly lower flea numbers relative to non-treated controls on all post-treatment count days (P<0.05). Metaflumizone provided >90% control of flea infestations up to 7 weeks following a single treatment.     

Evaluation of the effects of selamectin against adult and immature stages of fleas (Ctenocephalides felis felis) on dogs and cats

The adulticidal, ovicidal, and larvicidal effects of selamectin against flea (Ctenocephalides felis felis) infestations on dogs and cats were evaluated in a series of seven controlled and masked studies (three in cats, four in dogs). Animals were randomly allocated to treatment with either selamectin at a minimum dosage of 6mgkg(-1) in the commercial formulation or one of two negative-controls (0.9% NaCl solution or the vehicle from the commercial formulation). Treatments were administered topically in a single spot on the skin at the base of the neck in front of the scapulae. Speed of kill, measured by flea comb counts at 12h intervals during the 48h immediately following a single treatment on day 0, was evaluated in two studies. One study was in dogs and the other in cats, and each animal was infested with approximately 100 unfed viable adult fleas prior to treatment. Reductions in geometric mean flea counts for selamectin compared with saline were >98% between 24 and 36h after treatment in dogs, and between 12 and 24h after treatment in cats (P< or =0.0006). Efficacy in reducing flea egg hatch and larval development was evaluated in four studies, in which dogs and cats were treated once on day 0 and then repeatedly infested with approximately 600 fleas. Flea eggs were collected approximately for 72h after each infestation, on days 3, 7, 14, 21, and 30, counted, and cultured to determine their hatchability and subsequent larval development. Compared with the vehicle, selamectin was highly effective in reducing flea egg hatch (>92% in cats) and larval development (> or =95% for dogs and cats), and emergence of adults (97.8-100% for dogs, 85.6-100% for cats) for 30 days. Effects of exposure to hair coat debris were investigated in a study with dogs treated once on day 0 and repeatedly infested with 100 adult fleas. Debris (dander, flea faeces, hair, scales) was collected on days 1, 7, 14, 21, and 30 and added to normal flea eggs or larvae for incubation. Compared with debris from vehicle-treated dogs, debris from selamectin-treated dogs was highly effective in preventing egg hatch (>96%), in killing larvae (>98%) and in preventing larval development to adults (>99%) (P相似文献   

Comparative efficacy of the combination fipronil-(S)-methoprene and the combination permethrin-imidacloprid against Dermacentor reticulatus, the European dog tick, applied topically to dogs

This study compared the efficacy of two of the most widely veterinary-dispensed topical products for control of ticks on dogs: fipronil-(S)-methoprene and imidacloprid-permethrin. Eighteen healthy beagle dogs of both sexes were divided into three groups of six dogs. Group 1 served as the untreated control. Dogs in group 2 were treated with fipronil 10% + (S)-methoprene 9% w/v applied once on day 0, and those in group 3 were treated with imidacloprid 8.8% and permethrin 44% w/v, applied once on day 0. All dogs were infested with approximately 50 unfed Dermacentor reticulatus ticks on days 1, 7, 14, 21, 28, 35, and 42, and ticks remaining were counted and removed 48 hours after each infestation. The 48-hour efficacy of the fipronil-(S)-methoprene combination remained at 100% at all assessment points through and including day 37, declining to 95.30% on day 44. The 48-hour efficacy of the imidacloprid-permethrin combination peaked at 86.46% on day 9, decreased to 73.37% by the third week, and fell to 63.53% by the end of the study (day 44). Significantly (P < .05) fewer ticks were recovered from dogs treated with fipronil-(S)-methoprene or imidacloprid-permethrin than from untreated control dogs at each infestation. Notably, the dogs treated with fipronil-(S)-methoprene had significantly (P < .05) lower tick counts at every assessment than the dogs treated with imidacloprid-permethrin.     

Evaluation of the efficacy and safety of a novel formulation of metaflumizone in cats naturally infested with fleas in Europe

The efficacy and safety of a novel spot-on formulation of metaflumizone (ProMeris for Cats, Fort Dodge Animal Health, Overland Park, KS) was assessed in cats naturally infested with fleas in a multiregional, clinical field study. Sixteen veterinary clinics in Germany and eight clinics in France enrolled patients to the study. A total of 173 cats with flea infestation qualified as primary patients and were randomly allocated to one of the two treatments in a ratio of approximately 2:1 for metaflumizone (minimum dosage of 40mg/kg) or fipronil (at the recommended label rate). Clinical examinations and baseline parasite counts were performed on Day 0 prior to treatment. Flea counts and safety evaluations were repeated at approximately 2-week intervals for 8 weeks. Both treatments resulted in consistent reductions (>84%) in flea numbers throughout the study, but metaflumizone resulted in numerically higher reductions on most count days. Within groups the flea reduction was highly significant (p<0.0001) compared to baseline at all observation periods. The efficacy of metaflumizone against fleas compared to baseline was 91.0%, 89.4%, 90.8% and 90.7% at Day 14, 28, 42 and 56, respectively. The corresponding efficacies for fipronil were 91.7%, 86.9%, 84.6% and 87.7%. Metaflumizone was highly effective in controlling existing infestations of fleas on cats and was effective against reinfestation for at least 56 days. Metaflumizone showed a good tolerance profile in cats.     

Dose selection of selamectin for efficacy against adult fleas (Ctenocephalides felis felis) on dogs and cats

Selamectin, a novel avermectin, was evaluated in two controlled studies (one in Beagles, one in domestic shorthaired cats) to determine an appropriate topical dose for efficacy against adult Ctenocephalides felis felis (C. felis) fleas on dogs and cats for 1 month. For each study, animals were allocated randomly to four treatments. One treatment consisted of the inert formulation ingredients (vehicle) administered as a negative control, and the other three treatments consisted of a single topical dosage of 3, 6, or 9mgkg(-1) of selamectin. In each study, selamectin was administered as a topical dose applied to the skin in a single spot at the base of the neck in front of the scapulae. Dogs and cats were infested with 100 viable unfed C. felis (50 males and 50 females) on days 4, 11, 18, and 27. Seventy-two hours (+/-2h) after each infestation, on days 7, 14, 21, and 30, a comb count to determine the number of viable fleas present on each animal was performed. Efficacy of selamectin on day 30 was used to select an appropriate dose. For dogs and cats, percentage reductions in geometric mean flea comb counts for the three selamectin treatments ranged from 94. 6 to 100% on days 7, 14, and 21, compared with the negative-control treatment. On day 30, reductions in flea comb counts were 81.5, 94.7, and 90.8% for dogs, and 79.8, 98.0, and 96.2% for cats treated with selamectin at 3, 6, or 9mgkg(-1), respectively. For day 30 flea comb counts for dogs and cats, analysis of variance showed that the three selamectin treatments resulted in significantly (P< or =0.05) lower counts than did the negative-control treatment. For dogs and cats, geometric mean flea counts for selamectin administered at a dosage of 3mgkg(-1) were significantly (P< or =0.05) higher than those for the 6 and 9mgkg(-1) treatment dosages combined. There were no significant differences in flea counts between the 6 and 9mgkg(-1) treatments. This analysis was confirmed by linear-plateau modeling. Thus, the optimal dose of selamectin for efficacy against adult fleas for both dogs and cats, as estimated by the turning point (plateau) in the dose response curve, was 6mgkg(-1).     

Efficacy of selamectin against adult flea infestations (Ctenocephalides felis felis and Ctenocephalides canis) on dogs and cats

Selamectin was evaluated in eight controlled studies (4 in dogs, 4 in cats) to determine the efficacy of a single topical unit dose providing the recommended minimum dosage of 6mgkg(-1) against Ctenocephalides felis felis and Ctenocephalides canis fleas on dogs and against C. felis on cats. In addition, the effect of bathing on the efficacy of selamectin against C. felis was evaluated. Identical studies were performed in Beagles and domestic shorthaired cats. For each study, animals were allocated randomly to treatments of 8-12 animals each. All studies (dog studies A, B, C, and D and cat studies A, B, C, and D) evaluated the efficacy of selamectin without bathing. In addition, study C in both dogs and cats evaluated efficacy with a shampoo bath at 24h after dosing, and study D evaluated the efficacy of selamectin with water soaking at 2h after dosing or with a shampoo bath at 2-6h after dosing. Dog study B evaluated efficacy against C. canis, whereas all other studies used C. felis. In each study, selamectin was administered on day 0 as a topical dose that was applied directly to the skin in a single spot at the base of the neck in front of the scapulae. Dogs and cats were infested with approximately 100 viable unfed C. felis or C. canis on days 4, 11, 18, and 27. On days 7, 14, 21, and 30, approximately 72h after infestation, a comb count of the number of viable fleas present on each animal was made. For C. felis and C. canis for dogs and cats, compared with controls, selamectin achieved significant reductions in geometric mean adult flea comb counts of > or =98.9% on days 7, 14, and 21 in all eight studies. On day 30, the reduction for C. felis remained at or above 98.0%. This included the dogs and cats that were soaked with water or bathed with shampoo at 2, 6, or 24h after treatment. There were no significant (P>0.05) differences between the flea counts from selamectin-treated animals in these studies, regardless of bathing status. On day 30, a significant reduction of 91.8% was achieved against C. canis on dogs. Thus, these studies demonstrated that a single topical unit dose of selamectin was highly effective against adult fleas on dogs and cats for at least 27 days.     

Evaluation of efficacy of selamectin and fipronil against Ctenocephalides felis in cats

OBJECTIVE: To evaluate efficacy of monthly administration of selamectin and fipronil against Ctenocephalides felis in cats. DESIGN: Randomized controlled trial. ANIMALS: 36 healthy cats. PROCEDURE: Cats known to be free of fleas were infested with 100 unfed adult fleas on days -28 and -21. On days 0, 30, 60, 90, and 120, sixteen cats (8 pairs/treatment group) were treated by topical administration of selamectin (6 mg/kg [2.7 mg/lb] of body weight) or fipronil (7.5 mg/kg [3.4 mg/lb]). Four control cats (2 pairs) were not treated. On day -6 and every 2 weeks after initial treatment, comb counts were performed to detect fleas. Flea counts were recorded, and fleas (< or =50) that had been removed were replaced onto the cat. On day 89, fleas were not replaced. On day 91 and every 7 days until the end of the study (day 150), cats were challenged with 20 adult fleas. Flea counts were compared between and within treatments. RESULTS: 14 days after treatment, geometric mean flea counts were reduced by 71.2% by fipronil treatment and 35.3% by selamectin treatment. Both treatments resulted in 97 to 98% reduction in flea counts on day 29 and 99.8 to 100% reduction from day 44 to the end of the study. CONCLUSIONS AND CLINICAL Relevance: Selamectin is as effective as fipronil in treating infestation in cats housed for 3 months in a flea-infested environment under conditions known to support the flea life cycle and in protecting against subsequent weekly challenges with C felis for an additional 2 months.     

Dose determination of a novel formulation of metaflumizone plus amitraz for control of cat fleas (Ctenocephalides felis felis) and brown dog ticks (Rhipicephalus sanguineus) on dogs

A novel spot-on formulation containing metaflumizone and amitraz (ProMeris/ProMeris Duo for Dogs, Fort Dodge Animal Health, Overland Park, KS) was evaluated in a laboratory study to determine the appropriate dose for efficacy against fleas and ticks on dogs for 1 month. Thirty-six Beagles were randomly allocated to six equal groups and individually housed. One group remained nontreated. Another was treated with a placebo formulation (solvents with no active ingredients). Three groups of dogs were treated topically with the metaflumizone plus amitraz formulation (150mg of each of metaflumizone and amitraz/ml), at volumes providing doses of 10, 20 and 40mgeachactive/kg. The final group was treated with a commercial spot-on providing 6.7mgfipronil/kg. All treatments were applied to the skin at a single spot between the scapulae on Day 0. Dogs were infested with 50 adult brown dog ticks (Rhipicephalus sanguineus) on each of Days -2, 5, 12, 19, 26, 33 and 40, and with 100 cat fleas (Ctenocephalides felis felis) on Days -1, 6, 13, 20, 27, 34 and 41. Dogs were examined and parasites "finger counted" on Day 1 to estimate knock down efficacy, and all animals were comb counted to determine the numbers of viable fleas and ticks on Days 7, 14, 21, 28, 35 and 42. There were no significant differences in parasite counts between the nontreated control and the placebo-treated control groups for either fleas or ticks (P>0.05) except for very slight reductions on Day 7 for fleas and Day 14 for ticks, demonstrating that the formulation excipients had no activity. The qualitative finger counts on Day 1 indicated that all of the insecticidal treatments resulted in a noticeable reduction in flea and tick numbers within 1 day of treatment. All of the metaflumizone and amitraz treatments and fipronil resulted in significantly lower flea and tick numbers relative to nontreated controls on all posttreatment count days (P<0.05). For the metaflumizone plus amitraz treatments, mean flea and tick counts for the 10mg/kg dose were significantly higher than those for the 20mg/kg dose (P<0.05) from Day 21 on. There was no significant advantage provided by the 40mg/kg dose over the 20mg dose throughout the entire study (P>0.05). The two higher metaflumizone plus amitraz doses provided >95% control of fleas and >90% control of ticks for at least 35 days after treatment, and this level of control was similar to that of the commercial fipronil product. The 20mg/kg dose was selected as the minimum commercial dose rate to provide effective flea and tick control for at least 1 month following a single treatment.     

Evaluation of the efficacy and safety of a novel formulation of metaflumizone plus amitraz in dogs naturally infested with fleas and ticks in Europe

The efficacy and safety of a novel spot-on formulation of metaflumizone plus amitraz (ProMeris/ProMeris Duo for Dogs, Fort Dodge Animal Health, Overland Park, KS) was assessed in dogs naturally infested with ticks and/or fleas in a multiregional, clinical field study. Nineteen veterinary clinics in Germany and 11 clinics in France enrolled patients to the study. One hundred eighty one dogs with tick infestation and 170 dogs with flea infestation (plus three dogs harboring both ticks and fleas) qualified as primary patients and were randomly allocated to one of two treatments in a ratio of approximately 2:1 for metaflumizone plus amitraz (minimum dosage of 20 plus 20mg/kg) or fipronil (at the recommended label rate). Clinical examinations and baseline parasite counts were performed on Day 0 prior to treatment. Tick and/or flea counts and safety evaluations were repeated at intervals of about 2 weeks for 8 weeks. Both products resulted in consistent reductions in tick numbers (>81%) throughout the study, with metaflumizone plus amitraz giving consistently higher reductions in tick numbers. The efficacy against tick count compared with Day 0 was 97.6%, 93.5%, 89% and 94% at Day 14, 28, 42 and 56, respectively, for metaflumizone plus amitraz. The corresponding efficacies for fipronil were 86.3%, 81.1%, 84.8% and 86.1%. Within groups, the tick reduction was highly significant (P<0.0001) compared to baseline at all observation periods. Both treatments resulted in consistent (>89%) and highly significant (P<0.0001) reductions in flea numbers relative to the baseline counts throughout the study, although fipronil resulted in numerically higher reductions on each count day. The efficacy against fleas compared to baseline was 91.8%, 88.7%, 91.5% and 92.0% at Day 14, 28, 42 and 56, respectively, for metaflumizone plus amitraz. The corresponding efficacies for fipronil were 98.2%, 96.3%, 95.9% and 96.7%. Metaflumizone plus amitraz was highly effective in controlling existing infestations of fleas and ticks on dogs and was effective against reinfestation for at least 56 days. Metaflumizone plus amitraz showed a good tolerance profile in dogs.     

Comparison of the activity of selamectin, imidacloprid and fipronil for the treatment of cats infested experimentally with Ctenocephalides felis felis and Ctenocephalides felis strongylus

Twenty adult, domestic short hair cats were randomly allocated into four groups of five cats and housed in separated cages. Each cat was infested with 25 fleas Ctenocephalides felis felis and 25 Ctenocephalides felis strongylus and 2 days later (day 0) the cats in group 1, 2 and 3 received a spot on application of selamectin, imidacloprid or fipronil, respectively, while the cats in group four were not treated. The cats were combed 48 h later, the fleas were removed, counted and their subspecies were determined. All the cats were reinfested with the same number of the two subspecies of fleas on days 7, 14, 21, 29 and 35. The efficacy of each treatment was calculated 48 h after each infestation. The mean number of fleas on the control cats was 16.4 C. f. felis and 13.4 C. f. strongylus. The three treatments were effective for the first 31 days for C. f. felis and for the full 37 days for C. f. strongylus. Over the first 31 days, the efficacy of selamectin ranged from 89 to 100% and 85 to 100% against C. f. felis and C. f. strongylus, respectively, the efficacy of imidacloprid ranged from 76 to 100% and 92 to 100% and the efficacy of fipronil ranged from 98 to 100% and 97 to 100% against C. f. felis and C. f. strongylus. There were no significant differences between the control of C. f. felis and C. f. strongylus by the three products.     

Evaluation of the comparative efficacy of selamectin against flea (Ctenocephalides felis felis) infestations on dogs and cats in simulated home environments

The comparative efficacy of monthly administration of selamectin or lufenuron against Ctenocephalides felis felis on dogs and cats was evaluated over a 5-month period in flea-infested environments. Twenty-four dogs and 32 cats were randomly allocated to receiving a topical treatment with selamectin or an oral administration of tablets containing lufenuron/milbemycin oxime (for dogs) or lufenuron only (for cats). Each product was administered in accordance with the manufacturer's label recommendations. Eight dogs and four cats served as untreated sentinels. Treatments were administered on days 0, 30, 60, 90, and 120. Each animal received an application of 100 fleas on days -28 and -21, and then weekly applications of 20 fleas from days 91 through 147. Flea comb counts were performed on day -6, and every 2 weeks after day 0. From day 29 (dogs) or day 44 (cats) to day 150, geometric mean flea counts for selamectin were < or =0.4. Mean flea counts for animals assigned to treatment with selamectin were significantly lower (P=0.0001) than for animals assigned to treatment with lufenuron at all assessments after day 0.     

Efficacy of selamectin in the treatment and prevention of flea (Ctenocephalides felis felis) infestations on dogs and cats housed in simulated home environments

The efficacy of selamectin, a novel avermectin, in protecting dogs and cats against experimentally induced environmental flea (Ctenocephalides felis felis) infestations, was evaluated in a series of controlled and masked studies. Purpose-bred shorthaired cats and Beagles were randomly allocated to treatment with either selamectin at a minimum dosage of 6mgkg(-1) of body weight in the commercial formulation or the negative control treatment (vehicle only), and housed in controlled simulated home environments capable of supporting the flea life cycle. Day 0 was defined as the first day of treatment. Treatments were administered topically in a single spot on the skin at the base of the neck in front of the scapulae. In environmental challenge studies, which were designed to evaluate the efficacy of selamectin in the treatment and control of established flea infestations, dogs and cats were each infested with 100 fleas on days -28 and -21 and placed in carpeted rooms in order to establish high levels of active flea infestation prior to day 0. Treatments were administered monthly for 3 months. Flea comb counts were performed on days 14, 29, 44, 59, 74, and 90. Reductions in geometric mean flea comb counts for selamectin, compared with vehicle, were >99% from day 14 onwards for dogs, and >92% on day 29 and >99% on days 44, 59, 74, and 90 for cats (P=0.0001). In prevention of environmental infestation studies, dogs and cats were placed in environments capable of supporting flea infestations and given monthly treatments for 2 months, commencing on day 0. Animals were infested with 100 fleas on days 1 and 7, and flea comb counts were performed on days 29, 44, and 60. Reductions in geometric mean flea comb counts for selamectin, compared with vehicle, were >99% on days 29, 44, and 60 (P=0.0001) for dogs and cats. Monthly administration of selamectin to dogs and cats housed in environments highly suited to completion of the flea life cycle was shown to be highly effective in the treatment and prevention of flea infestations, without the need for supplementary environmental control measures.     

Evaluation of the CatanDog's tag to prevent flea infestations, inhibit flea reproduction or repel existing flea infestations on cats

To evaluate the ability of the CatanDog's tag to eliminate fleas, inhibit egg production and prevent flea infestations, six domestic shorthaired cats were randomly allocated to two treatment groups and housed individually in stainless steel metabolic cages. Three cats were each fitted with a CatanDog's tag; the other three cats were not fitted with tags and served as controls. Following a 42-day acclimation period, each of the six cats was infested with 100, 1-3 day post-emergence, adult Ctenocephalides felis felis (Bouché) on days 0, 7, 14, 21, and 27. Flea egg production was determined by collecting and enumerating eggs 2, 4 and 6 days after each infestation. Viability of eggs was determined by placing 100 eggs recovered from each cat in rearing media in an insect rearing chamber and determining adult emergence at 28 days. Adult fleas were recovered from cats 6 days post-infestation by thoroughly combing each cat to remove fleas. To determine if the tags provided protection from infestation, the six cats were placed into a 8.53mx4.36 m room with 400 cat fleas for 3h. Cats were then combed to remove and enumerate fleas. The CatanDog's tags had no significant effect upon egg production, egg viability, or adult fleas infesting cats. In addition there was no difference in the numbers of fleas recovered from the cats placed in the flea-infested room.     

Assay of two 10% (w/v) fipronil spot-on formulations against feline infestations with Ctenocephalides felis

A new fipronil-based spot-on formulation was evaluated against experimental flea infestations in cats in two studies. In both studies, eight cats served as negative controls (groups 1 and 4); on day 0, eight cats were treated with a 10% w/v fipronil-based spot-on solution (Effipro Spot-on, 0.5ml per cat, groups 2 and 5) and eight cats served as positive controls (Frontline Spot-on, 0.5ml per cat, groups 3 and 6). Each cat was infested on day - 1 with 50 fleas (study 1) and weekly (day 7-day 56) with 100 fleas (study 2). Geometric mean flea counts obtained 48h after the treatment or each re-infestation were reduced by 99.0 and 98.3% in groups 2 and 3, respectively, on day 2, compared to the negative control group. Cats were protected from re-infestations with an efficacy >99% for 58 days in group 5 and for 37 days in group 6.     

Effect of 0.29% w/w fipronil spray on adult flea mortality and egg production of three different cat flea, Ctenocephalides felis (Bouché), strains infesting cats.

To evaluate the effect of fipronil spray on adult flea mortality and flea egg production of three different cat flea, Ctenocephalides felis (Bouché) strains, 30 domestic short hair cats were randomly allocated into six groups of five cats each. On day 0, cats in groups 2, 4 and 6 were treated with fipronil at 5-6ml/kg. Cats in groups 1, 3 and 5 served as untreated controls. On days -2, 7, 14, 21, and 28 each cat was infested with 50 adult cat fleas. Groups 1 and 2 were infested with fleas from the Kansas1 Colony (KS1) strain. Groups 3 and 4 were infested with a recently colonized cat flea strain from Florida (R6). Groups 5 and 6 were infested with fleas from the ARC strain. The adulticidal activity of fipronil was determined by flea comb counts 48h after treatment and then 48h after each reinfestation. Any flea eggs produced during the infestations were collected and counted prior to the 48h comb counts. Fipronil spray was > or = 99.5% effective against adults of all three cat flea strains when applied during an active infestation. Fipronil spray provided > or = 98.2 and > or = 99.5% control of adult fleas and egg production, respectively, for all strains through week 2. On days 23 and 30 control of R6 adults and egg production was significantly lower than either the ARC or the KS1 strain. On day 30, control of R6 adults and egg production was 77.3 and 87.3%, respectively. Control of KS1 adults and egg production on day 30 was significantly lower than the ARC strain. Fipronil provided > or = 99.5 and > or = 99.9% control of ARC fleas and egg production, respectively, throughout the entire study. The susceptibility to fipronil for the three strains was also evaluated on filter paper pesticide bioassays. The R6 strain was found to be less susceptible than the KS1 and ARC strains. The LC(95) estimates for the strains were 10.13, 4.77 and 2.62mg/m(2) for the R6, ARC and KS1 strains, respectively.