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Steffen Rehbein - One of the best experts on this subject based on the ideXlab platform.

  • efficacy of a novel topical combination of fipronil s methoprene Eprinomectin and praziquantel against feline urinary bladder worm capillaria plica infection
    Veterinary Parasitology, 2014
    Co-Authors: Martin Knaus, Enstela Shukullari, Joseph Rosentel, Steffen Rehbein
    Abstract:

    Eprinomectin Praziquantel Nematodes Cat a b s t r a c t Infection with urinary capillarid bladder worms has been observed in cats worldwide. Although considered as generally causing no or little harm, infection with urinary capillarids may be associated with clinical disease which requires an appropriate treatment including the use of anthelmintics. Therefore, the efficacy of a novel topical combination formulation of fipronil 8.3% (w/v), (S)-methoprene 10% (w/v), Eprinomectin 0.4% (w/v), and praziquantel 8.3% (w/v) (BROADLINE®, Merial) was evaluated against urinary capillarids in naturally infected cats. Sixteen European Short Hair cats (5 male, 11 female) with capillarid eggs in their urine pre-treatment were included in the study. At the time of treatment, the cats were approximately ten months to eight years old and weighed 1.6–3.6 kg. Cats were ranked based on decreasing bodyweight and then randomly allocated within replicates of two animals to one of the treatment groups. Each cat in the treated group received one topical application of the combination product at the minimum therapeutic dose of 0.12 mL/kg body weight delivering 10 mg fipronil + 12 mg (S)-methoprene + 0.5 mg Eprinomectin + 10 mg praziquantel per kilogram of body weight while the cats allocated to the control group remained untreated. For parasite recovery, identification and count, cats were euthanized humanely 14 days after treatment. All untreated cats harboured Capillaria plica in their urinary bladders (range 4–12), while no capillarids were recovered from the eight treated cats. Thus, the efficacy of the novel topical combination against C. plica was 100%. All cats accepted the treatment well based on post-treatment observations and daily observations thereafter. No adverse events or other health problems were observed during

  • pharmacokinetics and metabolism of Eprinomectin in cats when administered in a novel topical combination of fipronil s methoprene Eprinomectin and praziquantel
    Veterinary Parasitology, 2014
    Co-Authors: Valerie Kvaternick, Steffen Rehbein, Martin Knaus, Michael Kellermann, Joseph Rosentel
    Abstract:

    Four studies were conducted to determine the pharmacokinetic characteristics and in vitro metabolism of Eprinomectin, a semi-synthetic avermectin, in cats. Pharmacokinetic parameters including bioavailability of Eprinomectin were determined in a parallel study design comprised of one group of eight cats which were treated once topically at 0.12 mL/kg bodyweight with BROADLINE(®), a novel combination product (fipronil 8.3% (w/v), (S)-methoprene 10% (w/v), Eprinomectin 0.4% (w/v) and praziquantel 8.3% (w/v)), delivering a dose of 0.5mg Eprinomectin per kg body weight, and a group of six cats which received 0.4% (w/v) Eprinomectin at 0.4 mg/kg bodyweight once by intravenous injection. For cats treated by topical application, the average Eprinomectin (B1a component) maximum plasma concentration (Cmax) was 20 ng/mL. The maximum concentrations were reached 24h after dosing in the majority of the animals (six of eight cats). The average terminal half-life was 114 h due to slow absorption ('flip-flop' kinetics). Following intravenous administration the average Cmax was 503 ng/mL at 5 min post-dose, and the mean elimination half-life was 23 h. Eprinomectin was widely distributed with a mean volume of distribution of 2,390 mL/kg, and the clearance rate was 81 mL/h/kg. Mean areas under the plasma concentration versus time curves extrapolated to infinity were 2,100 ngh/mL and 5,160 ngh/mL for the topical and intravenous doses, respectively. Topical Eprinomectin was absorbed with an average absolute bioavailability of 31%. In a second parallel design study, the dose proportionality of Eprinomectin after single topical administration of BROADLINE(®) was studied. Four groups of eight cats each were treated once topically with 0.5, 1, 2 or 5 times the minimum recommended dose of the combination, 0.12 mL/kg bodyweight. Based on comparison of areas under the plasma concentration versus time curves from the time of dosing to the last time point at which Eprinomectin B1a was quantified, and Cmax, dose proportionality was established. In addition, the metabolic pathway of Eprinomectin using cat liver microsomes, and plasma protein binding using cat, rat, and dog plasma were studied in vitro. Results of the analyses of Eprinomectin B1a described here showed that it is metabolically stable and highly protein bound (>99%), and thus likely to be, as with other species, excreted mainly as unchanged parent drug in the feces of cats.

  • efficacy of a novel topical combination of fipronil s methoprene Eprinomectin and praziquantel against larval and adult stages of the cat lungworm aelurostrongylus abstrusus
    Veterinary Parasitology, 2014
    Co-Authors: Martin Knaus, Joseph Rosentel, Theodore S Chester, Axel Kuhnert, Steffen Rehbein
    Abstract:

    The efficacy of a novel topical combination of fipronil 8.3% w/v, (S)-methoprene 10% w/v, Eprinomectin 0.4% w/v, and praziquantel 8.3% w/v (BROADLINE(®),(1) Merial) against larval and adult Aelurostrongylus abstrusus lungworms in cats was assessed in a controlled laboratory study. The study included 48 purpose-bred, short-haired cats which were each inoculated with 225 infective A. abstrusus larvae. The cats were formed into eight blocks based on pre-treatment bodyweight and were then, within each block, randomly allocated to one of six treatment groups: untreated control; treated once when A. abstrusus were expected to be third-stage larvae (4 days post inoculation [dpi]), fourth-stage larvae (7 dpi), immature adults (14 dpi) or adult nematodes (32 dpi), or treated twice, once when A. abstrusus were expected to be third-stage larval and once again when A. abstrusus were expected to be adult nematodes (4 dpi+32 dpi). Cats weighing ≥ 0.8-2.5 kg received one 0.3 mL applicator and cats weighing >2.5-7.5 kg received one 0.9 mL applicator. For determination of the efficacy of treatments, lungworm larval counts were established on faecal samples collected from all cats 32, 39, 46, 53 and 60 dpi. At each occasion from 46 dpi on, cats treated with fipronil, (S)-methoprene, Eprinomectin and praziquantel had significantly lower A. abstrusus larval counts than the untreated controls with percentage reductions of 91.6% (cats treated 14dpi; P=0.012), ≥ 98.9% (cats treated either 4 dpi, 7 dpi or 32 dpi; P 99.9% (cats treated 4 dpi+32 dpi; P<0.001) at 60 dpi. Thus, the novel topical combination of fipronil, (S)-methoprene, Eprinomectin and praziquantel was highly effective in the prevention and treatment of A. abstrusus lungworm infection in cats.

  • the efficacy of Eprinomectin extended release injection against hypoderma spp diptera oestridae in cattle
    Veterinary Parasitology, 2013
    Co-Authors: Steffen Rehbein, Larry L Smith, J E Holste, J L Lloyd
    Abstract:

    Abstract The efficacy of Eprinomectin in an extended-release injection (ERI) formulation was determined in cattle harboring naturally acquired infestations of first- or second- and third-stage larvae of Hypoderma spp. in three studies conducted according to the same protocol in the USA (two studies) and Germany (one study). Thirty cattle sourced from herds with a history of Hypoderma infestation were included in each study. Cattle were formed into replicates of three animals each on the basis of pre-treatment anti-Hypoderma antibody titers. Within replicates each animal was randomly allocated to one of the following treatments: ERI vehicle (control) at 1 mL/50 kg bodyweight, administered once on Day 0; Eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg Eprinomectin/kg), administered once on Day 0 (when larvae were expected to be first instars); or Eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg Eprinomectin/kg), administered once when larvae were second or third instars (study dependent, Day 73, 119, or 140). Treatments were administered by subcutaneous injection in front of the shoulder. In all studies, emerging and/or expressed Hypoderma larvae were recovered, speciated, and counted and viability was determined. Eprinomectin LAI treatment was 100% (p

  • the efficacy of Eprinomectin extended release injection against naturally acquired nematode parasites of cattle with special regard to inhibited fourth stage ostertagia larvae
    Veterinary Parasitology, 2013
    Co-Authors: James S Hunter, T A Yazwinski, S Yoon, J C Williams, Steffen Rehbein
    Abstract:

    Abstract The efficacy of Eprinomectin in an extended-release injection (ERI) formulation in the treatment of cattle harboring naturally acquired nematode populations (including inhibited nematodes) was evaluated. Five studies were conducted under a similar protocol in the USA, the UK, and in Germany. All study animals were infected by grazing naturally contaminated pastures. The adequacy of pasture infectivity was confirmed by examining tracer calves prior to allocation and treatment of the study animals. The cattle were of various breeds or crosses, weighing 79–491 kg, and aged approximately 6–15 months. In each study, 20 animals were infected by grazing, and then removed from pasture and housed in a manner to preclude further nematode infections for 8–16 days until treatment. Animals were blocked based on descending pre-treatment body weight and randomly allocated to one of two treatments: ERI vehicle (control) at 1 mL/50 kg body weight or Eprinomectin 5% (w/v) ERI at 1 mL/50 kg body weight (1.0 mg Eprinomectin/kg). Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. For parasite recovery and count, all study animals were humanely euthanized 14/15 days after treatment. Cattle treated with Eprinomectin ERI had significantly ( p Dictyocaulus viviparus, Capillaria spp., Cooperia oncophora , Cooperia pectinata , Cooperia punctata , Cooperia surnabada , Haemonchus placei , Nematodirus helvetianus , Oesophagostomum radiatum , Ostertagia lyrata , Ostertagia ostertagi , Trichostrongylus axei , Trichostrongylus colubriformis , Trichuris discolor , Trichuris skrjabini , and Trichuris spp.; developing fourth-stage larvae of Ostertagia spp. and Trichostrongylus spp.; and inhibited fourth-stage larvae of Cooperia spp., Haemonchus spp., Nematodirus spp., Oesophagostomum spp., Ostertagia spp., and Trichostrongylus spp. Animal treatments were well accepted, with no adverse reactions to treatment observed in any study animals. The results of this series of controlled studies demonstrated high therapeutic efficacy and acceptability of Eprinomectin ERI against pulmonary nematodes and a wide range of gastrointestinal parasitic infections, including inhibited gastrointestinal nematodes, in cattle.

James R Miller - One of the best experts on this subject based on the ideXlab platform.

  • lethal and sublethal effects of avermectin milbemycin parasiticides on the african malaria vector anopheles arabiensis
    Journal of Medical Entomology, 2012
    Co-Authors: Megan L Fritz, Edward D Walker, James R Miller
    Abstract:

    ABSTRACT Four cattle parasiticides of the avermectin/milbemycin class were examined for lethal and sublethal effects on the zoophilic, African malaria vector Anopheles arabiensis. Ivermectin, moxidectin, doramectin, and Eprinomectin were mixed with bovine blood and provided to laboratoryreared An. arabiensis in a membrane feeder. Ivermectin and Eprinomectin were lethal to An. arabiensis at low concentrations (LC50s of 7.9 ppb and 8.5 ppb, respectively). While the lethality of doramectin (LC50 of 23.9 ppb), was less than that of ivermectin and Eprinomectin, it markedly reduced egg development. The concentration of moxidectin required to reduce survivorship and egg production in An. arabiensis was >100 fold greater than for ivermectin or Eprinomectin. Moxidectin was weak in its actions against An. arabiensis relative to the other three chemicals. These results suggest that cattle treated with ivermectin or Eprinomectin in the prescribed range of low dosages as parasiticides have blood toxic to zoophilic mal...

  • lethal and sublethal effects of avermectin milbemycin parasiticides on the african malaria vector anopheles arabiensis
    Journal of Medical Entomology, 2012
    Co-Authors: Megan L Fritz, Edward D Walker, James R Miller
    Abstract:

    Four cattle parasiticides of the avermectin/milbemycin class were examined for lethal and sublethal effects on the zoophilic, African malaria vector Anopheles arabiensis. Ivermectin, moxidectin, doramectin, and Eprinomectin were mixed with bovine blood and provided to laboratory-reared An. arabiensis in a membrane feeder. Ivermectin and Eprinomectin were lethal to An. arabiensis at low concentrations (LC50s of 7.9 ppb and 8.5 ppb, respectively). While the lethality of doramectin (LC50 of 23.9 ppb), was less than that of ivermectin and Eprinomectin, it markedly reduced egg development. The concentration of moxidectin required to reduce survivorship and egg production in An. arabiensis was > 100 fold greater than for ivermectin or Eprinomectin. Moxidectin was weak in its actions against An. arabiensis relative to the other three chemicals. These results suggest that cattle treated with ivermectin or Eprinomectin in the prescribed range of low dosages as parasiticides have blood toxic to zoophilic malaria vectors. Regionally coordinated, seasonal treatment of cattle could suppress An. arabiensis populations, thereby reducing malaria transmission. Doramectin (although less toxic) would have population level effects on egg production if used in this manner.

S Yoon - One of the best experts on this subject based on the ideXlab platform.

  • the efficacy of Eprinomectin extended release injection against naturally acquired nematode parasites of cattle with special regard to inhibited fourth stage ostertagia larvae
    Veterinary Parasitology, 2013
    Co-Authors: James S Hunter, T A Yazwinski, S Yoon, J C Williams, Steffen Rehbein
    Abstract:

    Abstract The efficacy of Eprinomectin in an extended-release injection (ERI) formulation in the treatment of cattle harboring naturally acquired nematode populations (including inhibited nematodes) was evaluated. Five studies were conducted under a similar protocol in the USA, the UK, and in Germany. All study animals were infected by grazing naturally contaminated pastures. The adequacy of pasture infectivity was confirmed by examining tracer calves prior to allocation and treatment of the study animals. The cattle were of various breeds or crosses, weighing 79–491 kg, and aged approximately 6–15 months. In each study, 20 animals were infected by grazing, and then removed from pasture and housed in a manner to preclude further nematode infections for 8–16 days until treatment. Animals were blocked based on descending pre-treatment body weight and randomly allocated to one of two treatments: ERI vehicle (control) at 1 mL/50 kg body weight or Eprinomectin 5% (w/v) ERI at 1 mL/50 kg body weight (1.0 mg Eprinomectin/kg). Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. For parasite recovery and count, all study animals were humanely euthanized 14/15 days after treatment. Cattle treated with Eprinomectin ERI had significantly ( p Dictyocaulus viviparus, Capillaria spp., Cooperia oncophora , Cooperia pectinata , Cooperia punctata , Cooperia surnabada , Haemonchus placei , Nematodirus helvetianus , Oesophagostomum radiatum , Ostertagia lyrata , Ostertagia ostertagi , Trichostrongylus axei , Trichostrongylus colubriformis , Trichuris discolor , Trichuris skrjabini , and Trichuris spp.; developing fourth-stage larvae of Ostertagia spp. and Trichostrongylus spp.; and inhibited fourth-stage larvae of Cooperia spp., Haemonchus spp., Nematodirus spp., Oesophagostomum spp., Ostertagia spp., and Trichostrongylus spp. Animal treatments were well accepted, with no adverse reactions to treatment observed in any study animals. The results of this series of controlled studies demonstrated high therapeutic efficacy and acceptability of Eprinomectin ERI against pulmonary nematodes and a wide range of gastrointestinal parasitic infections, including inhibited gastrointestinal nematodes, in cattle.

  • the efficacy of Eprinomectin extended release injection against naturally acquired nematode parasites of cattle with special regard to inhibited fourth stage ostertagia larvae
    Veterinary Parasitology, 2013
    Co-Authors: S Yoon, T A Yazwinski, J C Williams, Steffen Rehbein
    Abstract:

    The efficacy of Eprinomectin in an extended-release injection (ERI) formulation in the treatment of cattle harboring naturally acquired nematode populations (including inhibited nematodes) was evaluated. Five studies were conducted under a similar protocol in the USA, the UK, and in Germany. All study animals were infected by grazing naturally contaminated pastures. The adequacy of pasture infectivity was confirmed by examining tracer calves prior to allocation and treatment of the study animals. The cattle were of various breeds or crosses, weighing 79-491 kg, and aged approximately 6-15 months. In each study, 20 animals were infected by grazing, and then removed from pasture and housed in a manner to preclude further nematode infections for 8-16 days until treatment. Animals were blocked based on descending pre-treatment body weight and randomly allocated to one of two treatments: ERI vehicle (control) at 1 mL/50 kg body weight or Eprinomectin 5% (w/v) ERI at 1 mL/50 kg body weight (1.0 mg Eprinomectin/kg). Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. For parasite recovery and count, all study animals were humanely euthanized 14/15 days after treatment. Cattle treated with Eprinomectin ERI had significantly (p<0.05) fewer of the following nematodes than the controls with overall reduction of parasite counts of ≥94%: adult Dictyocaulus viviparus, Capillaria spp., Cooperia oncophora, Cooperia pectinata, Cooperia punctata, Cooperia surnabada, Haemonchus placei, Nematodirus helvetianus, Oesophagostomum radiatum, Ostertagia lyrata, Ostertagia ostertagi, Trichostrongylus axei, Trichostrongylus colubriformis, Trichuris discolor, Trichuris skrjabini, and Trichuris spp.; developing fourth-stage larvae of Ostertagia spp. and Trichostrongylus spp.; and inhibited fourth-stage larvae of Cooperia spp., Haemonchus spp., Nematodirus spp., Oesophagostomum spp., Ostertagia spp., and Trichostrongylus spp. Animal treatments were well accepted, with no adverse reactions to treatment observed in any study animals. The results of this series of controlled studies demonstrated high therapeutic efficacy and acceptability of Eprinomectin ERI against pulmonary nematodes and a wide range of gastrointestinal parasitic infections, including inhibited gastrointestinal nematodes, in cattle.

  • therapeutic efficacy of Eprinomectin extended release injection against induced infections of developing fourth stage larvae and adult nematode parasites of cattle
    Veterinary Parasitology, 2013
    Co-Authors: Steffen Rehbein, S Yoon, D G Baggott, G C Royer, L G Cramer, Mark D Soll
    Abstract:

    The therapeutic efficacy of Eprinomectin in an extended-release injection (ERI) formulation was evaluated against induced infections of developing fourth-stage larval or adult gastrointestinal and pulmonary nematodes of cattle in a series of six studies under two identical protocols (three each for developing fourth-stage larvae or adults) conducted in the USA, Germany or the UK (two studies at each location, one per stage). Each study initially included 16 nematode-free cattle. The cattle were of various breeds or crosses, weighed 109-186.5 kg prior to treatment, and were approximately 4-7 months old. The animals were blocked based on pre-treatment bodyweight and then randomly allocated to treatment: Eprinomectin ERI vehicle (control) at 1 mL/50 kg body weight or Eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg Eprinomectin/kg) for a total of eight and eight animals in each group. Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. In each study, cattle were infected with a combination of infective third-stage larvae or eggs of gastrointestinal and pulmonary nematodes. Inoculation was scheduled so that the nematodes were expected to be fourth-stage larvae or adults at the time of treatment. For parasite recovery, all study animals were humanely euthanized and necropsied 14-15 (adult infections) or 21-22 days after treatment (developing fourth-stage larval infections). When compared with the vehicle-treated control counts, efficacy of Eprinomectin ERI against developing fourth-stage larvae and adults was ≥98% (p<0.05) for the following nematodes: Dictyocaulus viviparus, Bunostomum phlebotomum, Cooperia curticei, C. oncophora, C. surnabada, C. punctata, Haemonchus contortus, H. placei, Nematodirus helvetianus, Oesophagostomum radiatum, Oes. venulosum, Ostertagia leptospicularis, O. ostertagi, O. circumcincta, O. pinnata, O. trifurcata (developing fourth-stage larval infections only), Strongyloides papillosus, Trichostrongylus axei, T. colubriformis, and Trichuris ovis (adult infections only). All animals accepted the treatment well. No adverse reaction to treatments was observed in any animal in any study.

Megan L Fritz - One of the best experts on this subject based on the ideXlab platform.

  • lethal and sublethal effects of avermectin milbemycin parasiticides on the african malaria vector anopheles arabiensis
    Journal of Medical Entomology, 2012
    Co-Authors: Megan L Fritz, Edward D Walker, James R Miller
    Abstract:

    ABSTRACT Four cattle parasiticides of the avermectin/milbemycin class were examined for lethal and sublethal effects on the zoophilic, African malaria vector Anopheles arabiensis. Ivermectin, moxidectin, doramectin, and Eprinomectin were mixed with bovine blood and provided to laboratoryreared An. arabiensis in a membrane feeder. Ivermectin and Eprinomectin were lethal to An. arabiensis at low concentrations (LC50s of 7.9 ppb and 8.5 ppb, respectively). While the lethality of doramectin (LC50 of 23.9 ppb), was less than that of ivermectin and Eprinomectin, it markedly reduced egg development. The concentration of moxidectin required to reduce survivorship and egg production in An. arabiensis was >100 fold greater than for ivermectin or Eprinomectin. Moxidectin was weak in its actions against An. arabiensis relative to the other three chemicals. These results suggest that cattle treated with ivermectin or Eprinomectin in the prescribed range of low dosages as parasiticides have blood toxic to zoophilic mal...

  • lethal and sublethal effects of avermectin milbemycin parasiticides on the african malaria vector anopheles arabiensis
    Journal of Medical Entomology, 2012
    Co-Authors: Megan L Fritz, Edward D Walker, James R Miller
    Abstract:

    Four cattle parasiticides of the avermectin/milbemycin class were examined for lethal and sublethal effects on the zoophilic, African malaria vector Anopheles arabiensis. Ivermectin, moxidectin, doramectin, and Eprinomectin were mixed with bovine blood and provided to laboratory-reared An. arabiensis in a membrane feeder. Ivermectin and Eprinomectin were lethal to An. arabiensis at low concentrations (LC50s of 7.9 ppb and 8.5 ppb, respectively). While the lethality of doramectin (LC50 of 23.9 ppb), was less than that of ivermectin and Eprinomectin, it markedly reduced egg development. The concentration of moxidectin required to reduce survivorship and egg production in An. arabiensis was > 100 fold greater than for ivermectin or Eprinomectin. Moxidectin was weak in its actions against An. arabiensis relative to the other three chemicals. These results suggest that cattle treated with ivermectin or Eprinomectin in the prescribed range of low dosages as parasiticides have blood toxic to zoophilic malaria vectors. Regionally coordinated, seasonal treatment of cattle could suppress An. arabiensis populations, thereby reducing malaria transmission. Doramectin (although less toxic) would have population level effects on egg production if used in this manner.

J L Lloyd - One of the best experts on this subject based on the ideXlab platform.

  • the efficacy of Eprinomectin extended release injection against hypoderma spp diptera oestridae in cattle
    Veterinary Parasitology, 2013
    Co-Authors: Steffen Rehbein, Larry L Smith, J E Holste, J L Lloyd
    Abstract:

    Abstract The efficacy of Eprinomectin in an extended-release injection (ERI) formulation was determined in cattle harboring naturally acquired infestations of first- or second- and third-stage larvae of Hypoderma spp. in three studies conducted according to the same protocol in the USA (two studies) and Germany (one study). Thirty cattle sourced from herds with a history of Hypoderma infestation were included in each study. Cattle were formed into replicates of three animals each on the basis of pre-treatment anti-Hypoderma antibody titers. Within replicates each animal was randomly allocated to one of the following treatments: ERI vehicle (control) at 1 mL/50 kg bodyweight, administered once on Day 0; Eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg Eprinomectin/kg), administered once on Day 0 (when larvae were expected to be first instars); or Eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg Eprinomectin/kg), administered once when larvae were second or third instars (study dependent, Day 73, 119, or 140). Treatments were administered by subcutaneous injection in front of the shoulder. In all studies, emerging and/or expressed Hypoderma larvae were recovered, speciated, and counted and viability was determined. Eprinomectin LAI treatment was 100% (p

  • the efficacy of Eprinomectin extended release injection against hypoderma spp diptera oestridae in cattle
    Veterinary Parasitology, 2013
    Co-Authors: Steffen Rehbein, Larry L Smith, J E Holste, J L Lloyd
    Abstract:

    The efficacy of Eprinomectin in an extended-release injection (ERI) formulation was determined in cattle harboring naturally acquired infestations of first- or second- and third-stage larvae of Hypoderma spp. in three studies conducted according to the same protocol in the USA (two studies) and Germany (one study). Thirty cattle sourced from herds with a history of Hypoderma infestation were included in each study. Cattle were formed into replicates of three animals each on the basis of pre-treatment anti-Hypoderma antibody titers. Within replicates each animal was randomly allocated to one of the following treatments: ERI vehicle (control) at 1 mL/50 kg bodyweight, administered once on Day 0; Eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg Eprinomectin/kg), administered once on Day 0 (when larvae were expected to be first instars); or Eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg Eprinomectin/kg), administered once when larvae were second or third instars (study dependent, Day 73, 119, or 140). Treatments were administered by subcutaneous injection in front of the shoulder. In all studies, emerging and/or expressed Hypoderma larvae were recovered, speciated, and counted and viability was determined. Eprinomectin LAI treatment was 100% (p<0.05) efficacious against first- and second- or third-stage larvae of Hypoderma bovis (two studies) and Hypoderma lineatum (one study). All animals accepted the treatment well. No adverse reaction to treatments was observed in any animal in any study.