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The efficacy of afoxolaner plus milbemycin oxime (AFX + MO) combination chewables (NexGard Spectra®, Merial) and AFX single-entity chewables (NexGard®, Merial) against induced infestations with Dermacentor reticulatus ticks was evaluated in dogs. Thirty dogs were assigned to blocks of three animals each based on pre-allocation tick counts and were randomly allocated to one of three groups: untreated (control), treated with a combination of AFX + MO chewables to be as close as possible to the minimum effective dose of AFX + MO (2.5 + 0.5 mg per kg body weight), and treated with a combination of NexGard® chewables to be as close as possible to the minimum effective dose of AFX (2.5 mg per kg body weight). Treatments were administered orally once on day 0. Starting 2 days before treatment administration, each dog was infested with approximately 50 ticks weekly for six consecutive weeks. Live ticks were counted at ∼48 h post-treatment (removal count) and at ∼48 h (in situ counts) and ∼72 h (removal counts) following each post-treatment infestation. Treatment with both AFX + MO and NexGard® chewables rapidly eliminated the existing tick infestations (100 % efficacy) within 2 days following treatment administration. Weekly re-infestations were controlled for a minimum of 5 weeks with the efficacy ranging from 92.2 to 99.7 % based on ∼48 h post-treatment in situ counts and between 99.0 and 100 % based on ∼72 h post-treatment removal counts (p < 0.0001 at each occasion). This study demonstrated a high efficacy of both AFX + MO chewable and NexGard® chewable treatments against infestations of dogs with D. reticulatus ticks for at least 5 weeks. In addition, this study indicated no interference between the two compounds with respect to the acaricidal activity provided by AFX.

Speed of kill, repellent (anti-feeding) and acaricidal efficacy of an imidacloprid 10 % (w/w) /flumethrin 4.5 % (w/w) collar (Seresto(®), Bayer) and a spot-on formulation of fipronil 8.3 % (w/v) /(S)-methoprene 10 % (w/v) /eprinomectin 0.4 % (w/v) /praziquantel 8.3 % (w/v) (Broadline(®), Merial) against artificiallyinduced infestations with Ixodes ricinus on cats, were assessed in a parallel group design, randomised, controlled study. Twenty-four cats were included and randomly allocated to treatment groups or a non-treated control group. Starting on Day (D) 7 after treatment until D28, cats were each infested with 50 I. ricinus at weekly intervals. Ticks were counted in situ on the cats at 6, 12 and 24 h and upon removal 48 h after each infestation. Based on arithmetic means, Seresto(®) proved to be 100 % effective against adult I. ricinus at all assessment times (6, 12, 24 and 48 h after infestation) throughout the month-long study. Broadline(®) was 0 % to 16.7 % effective at 6 h, 26.8 % to 50.0 % effective at 12 h, while at 24 h after infestation efficacy peaked at 81.5 % on D15 declining to 31.5 % on D29. Based on the 48 h tick counts, the efficacy of Broadline(®) peaked at 100 % on D16 after treatment and decreased to 83.2 % by D30. The Seresto(®) collar provided significantly faster speed of kill and better persistent acaricidal effectiveness against Ixodes ricinus on cats compared to Broadline(®) spot-on. The additional repellent (anti-feeding) effect of Seresto(®) prevents parasites from taking a blood meal and thereby reduces the risk of vector-borne disease pathogen transmission.

This study was designed to compare the efficacy of two ectoparasiticides against adult fleas on dogs: a topical (DPP, dinotefuran-permethrin-pyriproxyfen) and a systemic (S, spinosad). Dogs (n = 48; 10.21-22.86 kg BW) were allocated to six groups of eight dogs each (C1, C4, DPP1, DPP4, S1, S4). Dogs in the treated groups were administered a topical (3.6 mL of DPP) or a tablet (665 or 1040 mg of S) on day 0. Infestations with 100 unfed fleas (Ctenocephalides felis) occurred on days -6, -1, 2, 7, 14, 21 and 28. An additional untreated group (QC, n = 6) was involved to evaluate the flea-anti-feeding efficacy. These dogs were infested once with 150 fleas prior to combing of at least 50 live fleas from each dog 5 or 10 min after infestation. In the treated group, dislodged dead and moribund fleas were collected from dogs 5, 10, 15 and 60 min (DPP1, S1) or 5, 10, 30 and 240 min (DPP4, S4) post-treatment and subsequent flea infestations on pans placed underneath the cages. Fleas were counted and removed from dogs by combing 1 (C1, DPP1, S1) or 4 h (C4, DPP4, S4) post-treatment and subsequent infestations. Quantitative PCR analysis of the canine cytochrome b gene was conducted on dislodged fleas collected from treated and control (QC) dogs 5 and 10 min after post-treatment infestations. The number of gene copies was used as a marker of blood volume ingested by fleas. Dislodgeability and insecticidal efficacy were calculated using arithmetic means. A rapid onset of killing was observed for DPP with 12.7 % of dead and moribund fleas being dislodged in average from dogs as soon as 5 min after infestation. DPP exhibited a significantly higher and sustained speed of kill than S. The average insecticidal efficacy was 86 ± 8.8 and 95.3 ± 2.1 % with DPP, whereas it was only 33.7 ± 19.9 and 57.6 ± 18.6 % with S at respectively 1 and 4 h after weekly reinfestations. The DPP combination significantly inhibited the feeding of fleas (89 % reduction) up to onset of flea mortality for 1-month post-treatment.

This study was designed to compare the therapeutic and residual efficacy for 1 month of three topical ectoparasiticides on mixed-bred dogs against the brown dog tick, Rhipicephalus sanguineus. Adult dogs (n = 32, 10.8-18.4 kg BW) were allocated to 4 groups (n = 8) and infested with 50 adult ticks on days -8, -2, 7, 14, 21, and 28. Within each group, dogs were treated topically on day 0 with a control solution (CS), Vectra 3D (DPP), Frontline Plus (FM), or K9 Advantix (IP). Ticks were enumerated on dogs 24 h after treatment and each subsequent tick infestation by in situ thumb count assessment without removal and at 48 h by combing and removal. Acaricidal efficacy was calculated using arithmetic means for all 24 and 48 h tick count assessments. From 42 to 56% of the total, infested ticks were found on dogs 48 h post-challenge in the CS group. Therapeutic efficacy for all treatments ranged from 45.5 to 64.6% after 48 h of infestation. Residual efficacy after FM treatment was consistently lower compared to DPP or IP treatments at the 24 h assessments on days 8, 22, 23, and 29. Residual efficacy measured at this last time point was 94.8% for DPP, 83.1% for IP, and 46.9% for FM. This study demonstrates that permethrin-based formulations (DPP and IP) provided a quicker onset of residual protection against brown dog ticks compared to FM. Although DPP and IP are both permethrin-based formulations, DPP exhibited consistently higher residual acaricidal efficacies and was the only treatment that provided >90% protection for 1 month at 24 h post challenge.

The objective of this study was to determine the empirical efficacy of imidacloprid 10 %/flumethrin 4.5 % (Seresto®) collars in preventing long-term transmission of Ehrlichia canis by infected Rhipicephalus sanguineus ticks to dogs. The study was a parallel group design, single centre, randomised, non-blinded, controlled, long-term efficacy study. The treatment group of 8 dogs was fitted with Seresto® collars, the untreated control group of 8 dogs received no collars. Ehrlichia canis-infected ticks were released into the dogs sleeping quarters at 14-day intervals up to Day +378. Control group dogs infected with E. canis were continuously replaced to keep the control sample size constant, and a total of 39 control dogs were required. The final clinical examination and blood sampling occurred on Day +420. The primary assessment criterion was the number of dogs infected with E. canis, as confirmed by IFA and PCR, and the secondary criterion was the acaricidal efficacy based on tick counts. All scheduled blood samples taken were subject to analyses for both PCR and IFA, but only positive cases are discussed. Up to Day +378, none of the collar-treated dogs were infected with E. canis, whereas 34 of the 35 untreated dogs enrolled before Day +371 were infected. The acaricidal efficacy of the collar ranged from 90 % to 100 % for the duration of the assessment period.

The present study demonstrated the efficacy of a pour-on formulation of fluazuron 2.5 % and flumethrin 1 % (Drastic Deadline eXtreme®) against Rhipicephalus decoloratus and Rhipicephalus microplus on cattle on pasture previously grazed by experimentally infested animals. Six tick-free cattle were placed on the pasture and treated 7 days later (Day 0) with the pour-on. They were retreated on Days 63, 126 and 189 and monthly tick counts were done. Mean numbers of adult R. decoloratus and/or R. microplus decreased from 53 and 14 on Days 56 and 112 respectively to 2 or less on all other occasions including Day 254. Compared to the numbers of R. decoloratus and/or R. microplus larvae collected from vegetation in the previous year, larval numbers declined by 40.7 % on Day 28, and thereafter reduction remained between 84 % and 100 %. Pairs of tracer calves placed on the pasture for 7 days each month were then held in pens and adult ticks that detached collected. Reduction in the numbers of R. decoloratus collected from tracer animals was 75 % on Day 56 and remained above 93 % except for Day 224 when it temporarily decreased to 78.5 %. Reduction in the numbers of R. microplus was 97.5 % on Day 28 and remained above 98 % until the conclusion of the study on Day 254. Treatment with the pour-on formulation of fluazuron and flumethrin resulted in a marked decrease in the numbers of R. decoloratus and/or R. microplus on treated cattle followed by a reduction in the numbers of larvae questing on the vegetation and ticks picked up by tracer calves. No other potential host species for R. decoloratus and/or R. microplus were present in the camps.

The objective of the study was to determine the sustained effectiveness of 10 % imidacloprid and 4.5 % flumethrin, incorporated in a slow-release matrix collar, in preventing Dipylidium caninum infection in dogs after repeated laboratory infestations with fleas infected with metacestodes of this tapeworm. Efficacy against infection with D. caninum was evaluated by infesting 16 dogs with cat fleas (Ctenocephalides felis) on study days 7, 14, 21, 28, 35 and 42, from batches suitably infected with D. caninum metacestodes. Prior to each post-treatment infestation the D. caninum infection rate for the fleas was determined by microscopically examining 100 fleas for D. caninum metacestodes. The D. caninum prevalence in the fleas used for infestations ranged from 23 % to 52 %. Medicated collars were fitted to 8 of the dogs on study day 0. The weight of the IVP collars varied between 35.48 g and 38.48 g (average 37.16 g), whilst animal weight varied between 12.20 kg and 17.98 kg (treated group, n = 8, average 14.79 kg). Seven days later infestation of each of the 16 dogs with 250 fleas commenced. Infestations continued at weekly intervals until Day 42 with efficacy against fleas evaluated 24 hours after each infestation. From Days 21 to 74, infection of the dogs with D. caninum was verified (daily examination of faeces and cages for the presence of expelled proglottids). Calculation of prophylactic effectiveness of the collars in preventing infection with D. caninum was based on the difference in geometric mean numbers of scoleces between groups at necropsy on Day 75. Effective prevention of infection with D. caninum was found to be 96.6 %. Efficacy of the collars against fleas was ≥ 99.9 % for the duration of the assessment period. Newly acquired infestations of fleas are rapidly eliminated by the insecticidal components of the medicated collars over a period of several months. In the event of fleas being infected with metacestodes, with D. caninum can be prevented in collared dogs, concurrently reducing the likelihood of transmission to humans.

Cat fleas (Ctenocephalides felis) and the castor bean tick (Ixodes ricinus) cause discomfort and health effects due to bites and ingestion of blood and they serve as vectors for several animal and human pathogens. Effectiveness of a novel 10 % w/v fipronil spot-on (Eliminall®/Exproline vet™, marketed by Pfizer Animal Health and registered and manufactured by Krka, d.d., Novo mesto) was confirmed against these parasites on experimentally infested cats. Two parallel, unicentre and masked controlled studies were conducted with European mixed breed and mixed sex cats. Cats were allocated randomly to one of two treatment groups based on either pre-treatment flea counts (study 1) or pre-treatment tick counts (study 2). In each of the study, eight animals served as control, while another eight animals were treated once topically with the unit label dose of 50 mg fipronil per cat (10.6-23.8 mg/kg). At each reinfestation, animals were infested with approximately 100 fleas or 60 ticks to achieve adequate infestation rates. Parasites were removed and counted on days 2, 9, 16, 23, 30 and 37, 48 h after the treatment or experimental infestation. Excellent effectiveness was demonstrated on day 2 (100 and 94 % efficacy against fleas and ticks, respectively) and lasted for up to 5 weeks (efficacy ≥96 %) against fleas and up to 4 weeks against ticks (efficacy ≥94 %). The product was well tolerated and no adverse reactions were observed.

This laboratory study compared the efficacy of two treatment regimens using an imidacloprid (10%)/moxidectin (2.5%) topical formulation (Advocate, Bayer) on dogs with generalised demodicosis. Sixteen dogs were randomly allocated to two equal groups. One group was treated at 28-day intervals for 12 weeks and the second group at weekly intervals for 15 weeks. Mite numbers were estimated and demodectic lesions were evaluated on each dog before treatment and at approximately 28-day intervals thereafter. Consistently greater reduction in mite numbers was recorded for the weekly treatment regimen. Dogs treated at weekly intervals exhibited markedly fewer clinical signs and greater hair regrowth and weight gain than those treated at 28-day intervals. To assess the safety of a weekly treatment interval in dogs, a study was done in which the investigational compound was administered at weekly intervals at five times the recommended dose for a period of 16 consecutive weeks. Apart from transient erythema at the site of administration in one dog and scaliness of the skin in another, no clinical signs of toxicity could be observed. Assessment of 27 blood parameters indicated that only basophils were outside the reference values on days +13 and +69, during the safety trial period.