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Rehbein S, Hamel D, Yoon S, Johnson C. Efficacy of eprinomectin topical solution and eprinomectin extended-release injection treatments against developing larval and adult Chabertia ovina and Oesophagostomum venulosum - two less common cattle nematode parasites. Vet Parasitol 2022; 312:109837. [DOI: 10.1016/j.vetpar.2022.109837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 10/17/2022] [Accepted: 10/22/2022] [Indexed: 11/06/2022]
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Geurden T, Smith ER, Vercruysse J, Yazwinski T, Rehbein S, Nielsen MK. Reflections and future directions for continued development and refinement of guidelines for anthelmintic efficacy studies. Vet Parasitol 2022; 307-308:109741. [PMID: 35667202 DOI: 10.1016/j.vetpar.2022.109741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 11/19/2022]
Abstract
This reflection paper complements the WAAVP (World Association for the Advancement of Veterinary Parasitology) general anthelmintic efficacy guideline, which outlines the general principles of anthelmintic efficacy evaluation across all animal host species. It provides background to the recommendations made in the WAAVP general anthelmintic efficacy guideline, with insights into the discussions leading to specific recommendations in the general guideline or the absence thereof. Furthermore, this paper discusses recent technological advancements with potential value to the evaluation of anthelmintic efficacy that may be considered for future versions of the general or species-specific guidelines if supported by sufficient levels of evidence. Finally, it also identifies potential research questions, such as the statistical approach for comparing worm counts between groups of animals.
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Affiliation(s)
| | - Emily R Smith
- Center for Veterinary Medicine, USA Food and Drug Administration, Rockville, USA
| | - Jozef Vercruysse
- Faculty of Veterinary Medicine, University of Gent, Salisburylaan 133, B-9820 Merelbeke, Belgium
| | - Tom Yazwinski
- Department of Animal Science, University of Arkansas, Fayetteville, AR, USA
| | - Steffen Rehbein
- Boehringer Ingelheim Vetmedica GmbH, Kathrinenhof Research Center, Rohrdorf, Germany
| | - Martin K Nielsen
- M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, USA
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Hamel D, Kunkle BN, Liebstein M, Bader J, Shryock J, Visser M, Yoon S, Fankhauser B, Rehbein S. Eprinomectin 5% w/v extended-release injection for the treatment of larval and/or adult Bunostomum phlebotomum, Haemonchus contortus, H. placei, Nematodirus helvetianus, Oesophagostomum radiatum, and Trichostrongylus colubriformis infections in cattle. Parasitol Res 2022; 121:2173-2178. [PMID: 35503138 DOI: 10.1007/s00436-022-07529-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 04/24/2022] [Indexed: 11/24/2022]
Abstract
In an effort to generate data for regulatory purposes on the therapeutic efficacy of eprinomectin 5% w/v extended-release injection (Eprinomectin ERI) (LongRange®, Boehringer Ingelheim) against infections of immature and adult stages of some nematode species (or stages) which are generally less common or predominantly seen in younger cattle, nine studies (minimum two per parasite and stage) were conducted in the USA and Germany. A total of 218 young cattle were included in seven experimentally induced infection studies (180 animals) and two studies with naturally acquired nematode infections (38 animals), which were compliant with WAAVP and VICH guidelines. In each study, cattle were randomly assigned into groups which received 1 mL per 50 kg body weight of either saline (controls) or Eprinomectin ERI (equivalent to 1 mg eprinomectin per kg body weight) via subcutaneous injection when the parasites were developing fourth-stage larval (L4) or adult nematodes. Following necropsy and parasite recovery, percentage efficacy was calculated based on the comparison of geometric mean nematode counts of the Eprinomectin ERI- vs. the saline-treated animals. Eprinomectin ERI-treated cattle had significantly (p < 0.05) lower counts of each species and stage of nematodes than the controls. Eprinomectin ERI treatment was demonstrated to be efficacious (> 90%) against L4 and adult Bunostomum phlebotomum and Nematodirus helvetianus; against L4 Haemonchus placei, Oesophagostomum radiatum, and Trichostrongylus colubriformis; and against adult H. contortus. Percentage efficacy against L4 H. contortus was variable (69.6 to 100%). All treatments were well accepted, and no treatment-related health problems were observed in any study.
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Affiliation(s)
- Dietmar Hamel
- Boehringer Ingelheim Vetmedica GmbH, Kathrinenhof Research Center, Walchenseestr. 8-12, 83101, Rohrdorf, Germany.
| | - Bruce N Kunkle
- Boehringer Ingelheim Animal Health USA Inc., Missouri Research Center, 6498 Jade Road, Fulton, MO, 65251, USA
| | - Martin Liebstein
- Boehringer Ingelheim Animal Health USA Inc., Missouri Research Center, 6498 Jade Road, Fulton, MO, 65251, USA
| | - Jonathan Bader
- Boehringer Ingelheim Animal Health USA Inc., Missouri Research Center, 6498 Jade Road, Fulton, MO, 65251, USA
| | - Jeffrey Shryock
- Boehringer Ingelheim Animal Health USA Inc., Missouri Research Center, 6498 Jade Road, Fulton, MO, 65251, USA
| | - Martin Visser
- Boehringer Ingelheim Vetmedica GmbH, Kathrinenhof Research Center, Walchenseestr. 8-12, 83101, Rohrdorf, Germany
| | - Stephen Yoon
- Boehringer Ingelheim Animal Health USA Inc., 3239 Satellite Boulevard, Duluth, GA, 30096-4640, USA
| | - Becky Fankhauser
- Boehringer Ingelheim Animal Health USA Inc., 3239 Satellite Boulevard, Duluth, GA, 30096-4640, USA
| | - Steffen Rehbein
- Boehringer Ingelheim Vetmedica GmbH, Kathrinenhof Research Center, Walchenseestr. 8-12, 83101, Rohrdorf, Germany
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Naturally acquired ovine-adapted nematode infections in young cattle and their treatment with eprinomectin 5% w/v extended-release injection. Parasitol Res 2022; 121:1811-1815. [PMID: 35394207 DOI: 10.1007/s00436-022-07515-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 04/04/2022] [Indexed: 10/18/2022]
Abstract
The objective of this controlled study was to determine the anthelmintic efficacy of eprinomectin 5% w/v extended-release injection (Eprinomectin ERI; LONGRANGE®, Boehringer Ingelheim Animal Health) against primarily ovine-adapted gastrointestinal strongylid nematode (GIN) parasites in naturally infected young cattle. Eighteen calves which grazed on a sheep-dominated mixed sheep-cattle farm were randomly allocated into two equal groups (saline [control] or Eprinomectin ERI, administered each at 1 mL/50 kg body weight once subcutaneously), treated and euthanized 14 days thereafter for a differential GIN count. Ten species of strongylid nematodes were recovered from the control calves (ovine-adapted Haemonchus contortus, Teladorsagia circumcincta, Trichostrongylus colubriformis, Cooperia curticei, Nematodirus battus, Chabertia ovina; bovine-adapted Ostertagia ostertagi, Cooperia oncophora, Nematodirus helvetianus; 'generalist' Trichostrongylus axei). Adult GIN counts ranged from 1,540 to 5,244 for the control calves and from zero to 110 for the Eprinomectin ERI-treated calves. Accepting the International Cooperation on Harmonisation of Technical Requirements for Registration of Veterinary Medicinal Products anthelmintic guidelines criteria on adequacy of infections to be demonstrated in the control animals, this study showed that Ch. ovina, C. curticei, H. contortus, N. battus, T. axei, and T. colubriformis were reduced significantly (p < 0.0001) by ≥ 98.7% in the animals treated with Eprinomectin ERI. In conclusion, Eprinomectin ERI treatment was efficacious against a range of ovine-adapted nematode parasites in naturally infected young cattle.
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MÜLLER PM, MEDEIROS ESD, MOTA RA, ROLIM MBDQ, COLOMBO MV, RÜBENSAM G, BARRETO F, SILVA DDD, SILVA TIBD. Avermectins residues in milk produced in the state of Pernambuco. FOOD SCIENCE AND TECHNOLOGY 2020. [DOI: 10.1590/fst.21919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Johnson J, Kasimanickam VR, Kastelic JP, Kasimanickam RK. Reduced gastrointestinal worm burden following long term parasite control improves body condition and fertility in beef cows. Vet Parasitol 2020; 287:109259. [PMID: 33035775 DOI: 10.1016/j.vetpar.2020.109259] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 09/26/2020] [Accepted: 09/27/2020] [Indexed: 01/10/2023]
Abstract
The objective of this study was to compare effects of gastrointestinal parasite control over a long vs short term (PC-LT vs. PC-ST) on fecal parasite load, body condition and pregnancy in beef cows. On Day 0, fecal samples were collected from Angus cross cows (n = 1462) and they were assigned a body condition score (BCS: 1, emaciated; 9, Obese) and randomly divided into two groups (within location) to receive extended-release eprinomectin [PC-LT; n = 749; 50 mg/50 kg body weight (BW)] or pour-on ivermectin (PC-ST; n = 713; 25 mg/50 kg BW). All cows were synchronized with CO-Synch + CIDR [100 μg GnRH + progesterone vaginal insert (CIDR) application on Day 20, CIDR removal +25 mg PGF2a on Day 27, and artificial insemination +100 μg GnRH on Day 30 (66 h after CIDR removal)] protocol, artificially inseminated (AI; Day 30) and on Day 44, exposed to breeding bulls (1:40 bull to cow ratio) for the remainder of the 85 day breeding season. On Day 90, a second fecal sample was collected from all cows and the cows were examined to determine pregnancy/AI (P/AI). All cows were assigned a BCS on Day 180 and re-examined to determine pregnancy/breeding season (P/BS). Worm egg count per gram of feces (FEG) was determined by McMaster method. There were no differences (P > 0.1) between PC-LT and PC-ST groups on Day 0 for FEG (46.9 ± 13.1 vs 42.6 ± 15.2, respectively; mean ± SEM) or BCS (5.95 ± 0.12 vs 6.00 ± 0.20). The mean FEG (PC-LT, 12.3 ± 4.7 vs. PC-ST, 131.3 ± 10.9) on Day 90 and BCS (PC-LT, 6.04 ± 0.07 vs. PC-ST, 5.79 ± 0.13) on Day 180 differed (P < 0.05) between the two groups. Mean P/AI [PC-LT, 62.9 %; (471/749) vs PC-ST, 57.4 %; (409/713)] and P/BS [PC-LT, 92.9 % (696/749) vs PC-ST, 90.0 (642/713)] also differed (P < 0.05). Lower FEG at Day 90 resulted in moderate to good body condition at Day 180 and cows with moderate to good body condition at Day 180 had higher P/BS. In conclusion, lower worm burden with long-term parasite control reduced FEG and improved BCS, P/AI and P/BS.
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Affiliation(s)
- Jerimyah Johnson
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA.
| | - Vanmathy R Kasimanickam
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA.
| | - John P Kastelic
- Department of Production Animal Health, University of Calgary, Faculty of Veterinary Medicine, Calgary, AB, Canada.
| | - Ramanathan K Kasimanickam
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA.
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Efficacy and production benefits following use of eprinomectin extended-release injection in pastured dairy heifers. Vet Parasitol 2020; 282:109157. [PMID: 32497935 DOI: 10.1016/j.vetpar.2020.109157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/24/2020] [Accepted: 05/25/2020] [Indexed: 11/20/2022]
Abstract
A study was conducted in grazing dairy heifers to assess anthelmintic efficacy and production responses in dairy heifers treated with a single injection of eprinomectin in an extended-release formulation over a 123 day-period. The study was conducted on a pasture-based dairy in the Southeastern United States (North Carolina) over the summer months. Sixty crossbred dairy heifers were weighed and randomly allocated into 2 groups. One group (n = 30) was given 5% eprinomectin subcutaneously in the cervical region while the other group (n = 30) was given an equivalent volume of saline. Calves were weighed every 30 days throughout the trial for calculation of average daily gain and differences in overall weight gain. In addition, fecal samples were collected at days 0, 30, 60, 90 and 123 for worm egg count and coproculture. Both groups of cattle had similar worm egg concentrations at the start of the study. However, the control group had increasing concentrations of fecal worm eggs throughout the summer months while the heifers that received eprinomectin had minimal fecal worm eggs. The primary parasite species identified in this study were Haemonchus placei, Cooperia species and Ostertagia. The heifers that received eprinomectin gained 105 + 2.8 kg during the 123-day study period, representing an average daily gain of 0.85 kg/day compared to 78.3 + 4.1 kg (0.64 kg/day) for the control group. This represented a 33 % increase in average daily gain associated with deworming. The results of this study indicate that a single dose of extended-release eprinomectin was sufficient to control parasites through a 123-day summer grazing season and that administration of the anthelmintic had a significant impact on weight gain.
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Navarre CB. Epidemiology and Control of Gastrointestinal Nematodes of Cattle in Southern Climates. Vet Clin North Am Food Anim Pract 2020; 36:45-57. [PMID: 32029188 DOI: 10.1016/j.cvfa.2019.11.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Control of gastrointestinal nematodes (GIN) can have both economic and health benefits for cattle operations in the southern United States. In the past several decades, GIN control has relied almost exclusively on the use of anthelmintics. With the increase in anthelmintic resistance new strategies must be developed. Anthelmintic use should be minimized by integrating grazing management and a good herd health program into GIN control programs. This takes knowledge of GIN biology and epidemiology in the region (climate and weather) combined with specific information from the ranch.
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Affiliation(s)
- Christine B Navarre
- School of Animal Sciences, Louisiana State University Agricultural Center, Louisiana State University, 111 Dalrymple Building, 110 LSU Union Square, Baton Rouge, LA 70803-0106, USA.
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Lia RP, Rehbein S, Giannelli A, Fankhauser B, Otranto D. LONGRANGE® (eprinomectin 5% w/v extended-release injection) efficacy against Hypoderma lineatum in an endemic area in southern Italy. Parasit Vectors 2019; 12:231. [PMID: 31088510 PMCID: PMC6518729 DOI: 10.1186/s13071-019-3475-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/30/2019] [Indexed: 11/21/2022] Open
Abstract
Background Despite intensive control measures including governmental campaigns using highly-efficacious systemic insecticides, there is evidence for persisting or recurring bovine Hypoderma species populations in parts of Europe, the USA and Canada. The present study evaluated the efficacy of LONGRANGE® (eprinomectin 5% w/v extended-release injection) against the infestation of cattle with Hypoderma lineatum, which is considered to be the predominant bovine warble fly in southern Europe and in North America. Methods Thirty-six local breed cattle sourced in an endemic area in southern Italy and confirmed positive for Hypoderma exposure by ELISA were randomly assigned to three groups of 12 animals each. Cattle of one group served as control and received saline injectable solution, whereas those in the two other groups received LONGRANGE® by subcutaneous injection. LONGRANGE® was administered once, either when Hypoderma larvae were expected to be first-instars (L1) or after warbles development, with Hypoderma larvae moulting to the second-(L2) and third-(L3) instars. Cattle were checked at intervals for warbles and Hypoderma larvae were collected, examined for their viability and morphologically identified. The detection of Hypoderma on cattle was terminated when warbles were no longer emerging. Results All intact larvae collected were identified as H. lineatum. No live larvae were collected from any animal treated with LONGRANGE® while live specimens were sampled from nine of the 12 control cattle (1 to 9 larvae per animal) (P = 0.0001 at α = 0.05). LONGRANGE® treatment was well accepted and no adverse events related to treatment or other health problems were observed. Conclusions This study confirmed the continued ‘preventive’ (efficacy against migrating L1) and ‘therapeutic’ (efficacy against L2 and L3 in warbles) efficacy of LONGRANGE® against H. lineatum infestation of cattle under contemporary field conditions.
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Affiliation(s)
- Riccardo Paolo Lia
- Department of Veterinary Medicine, University of Bari, Str. prov. per Casamassima Km 3, Valenzano, 70010, Bari, Italy
| | - Steffen Rehbein
- Boehringer Ingelheim Vetmedica GmbH, Kathrinenhof Research Center, Walchenseestr. 8-12, 83101, Rohrdorf, Germany
| | - Alessio Giannelli
- Department of Veterinary Medicine, University of Bari, Str. prov. per Casamassima Km 3, Valenzano, 70010, Bari, Italy
| | - Becky Fankhauser
- Boehringer Ingelheim Animal Health USA, Inc, 3239 Satellite Blvd, Duluth, GA, 30096-4640, USA
| | - Domenico Otranto
- Department of Veterinary Medicine, University of Bari, Str. prov. per Casamassima Km 3, Valenzano, 70010, Bari, Italy.
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Rehbein S, Baggott DG, Johnson EG, Kunkle BN, Yazwinski TA, Yoon S, Cramer LG, Soll MD. Nematode burdens of pastured cattle treated once at turnout with eprinomectin extended-release injection. Vet Parasitol 2012; 192:321-31. [PMID: 23273928 DOI: 10.1016/j.vetpar.2012.11.038] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The efficacy of eprinomectin in an extended-release injection (ERI) formulation was evaluated against infections with third-stage larvae or eggs of gastrointestinal and pulmonary nematodes in cattle under 120-day natural challenge conditions in a series of five studies conducted in the USA (three studies) and in Europe (two studies). For each study, 30 nematode-free (four studies) or 30 cattle harboring naturally acquired nematode infections (one study) were included. The cattle were of various breeds or crosses, weighed 107.5-273 kg prior to treatment and aged approximately 4-11 months. For each study, animals were blocked based on pre-treatment bodyweight and then randomly allocated to treatment: ERI vehicle (control) at 1 mL/50 kg bodyweight or Eprinomectin 5% (w/v) ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg) for a total of 15 and 15 animals in each group. Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. In each study, all animals grazed one naturally contaminated pasture for 120 days. At regular intervals during the studies, fecal samples from all cattle were examined for nematode egg and larval counts. In four studies pairs of tracer cattle were used to monitor pasture infectivity at 28-day intervals before and/or during the grazing period. All calves were weighed before turnout onto pasture and at regular intervals until housing on Day 120. For parasite recovery, all study animals were humanely euthanized 27-30 days after removal from pasture. Cattle treated with Eprinomectin ERI had significantly (p<0.05) fewer strongylid eggs (≤1 egg per gram; egg count reduction≥94%) than the control cattle and zero lungworm larvae at each post-treatment time point. At euthanasia, cattle treated with Eprinomectin ERI had significantly (p<0.05) fewer of the following nematodes than the ERI vehicle-treated (control) cattle with overall reduction of nematode counts by >92%: Dictyocaulus viviparus (adults and fourth-stage larvae (L4), Bunostomum phlebotomum, Cooperia curticei, Cooperia oncophora, Cooperia punctata, Cooperia surnabada, Cooperia spp. inhibited L4, Haemonchus contortus, Haemonchus placei, Haemonchus spp. inhibited L4, Nematodirus helvetianus, Nematodirus spp. inhibited L4, Oesophagostomum radiatum, Oesophagostomum spp. inhibited L4, Ostertagia leptospicularis, Ostertagia lyrata, Ostertagia ostertagi, Ostertagia spp. inhibited L4, Trichostrongylus axei, Trichostrongylus colubriformis, Trichostrongylus spp. inhibited L4, Trichuris discolor, and Trichuris ovis. Over the 120-day grazing period, Eprinomectin ERI-treated cattle gained between 4.8 kg and 31 kg more weight than the controls. This weight gain advantage was significant (p<0.05) in three studies. All animals accepted the treatment well. No adverse reaction to treatment was observed in any animal in any study.
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Affiliation(s)
- S Rehbein
- Merial GmbH, Kathrinenhof Research Center, Walchenseestr. 8-12, 83101 Rohrdorf, Germany.
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An eprinomectin extended-release injection formulation providing nematode control in cattle for up to 150 days. Vet Parasitol 2012; 192:313-20. [PMID: 23273777 DOI: 10.1016/j.vetpar.2012.11.037] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of 10 dose confirmation studies was conducted to evaluate the persistent activity of an extended-release injectable (ERI) formulation of eprinomectin against single point challenge infections of gastrointestinal and pulmonary nematodes of cattle. The formulation, selected based on the optimal combination of high nematode efficacy, appropriate plasma profile, and satisfactory tissue residue levels, includes 5% poly(D,L-lactide-co-glycolic)acid (PLGA) and is designed to deliver eprinomectin at a dose of 1.0mg/kg bodyweight. Individual studies, included 16-30 cattle blocked based on pre-treatment bodyweight and randomly allocated to treatment with either ERI vehicle or saline (control), or the selected Eprinomectin ERI formulation. Treatments were administered once at a dose volume of 1 mL/50 kg bodyweight by subcutaneous injection in front of the shoulder. In each study, cattle were challenged with a combination of infective stages of gastrointestinal and/or pulmonary nematodes 100, 120 or 150 days after treatment and were processed for parasite recovery according to standard techniques 25-30 days after challenge. Based on parasite counts, Eprinomectin ERI (1mg eprinomectin/kg bodyweight) provided >90% efficacy (p<0.05) against challenge with Cooperia oncophora and Cooperia surnabada at 100 days after treatment; against challenge with Ostertagia ostertagi, Ostertagia lyrata, Ostertagia leptospicularis, Ostertagia circumcincta, Ostertagia trifurcata, Trichostrongylus axei, and Cooperia punctata at 120 days after treatment; and against challenge with Haemonchus contortus, Bunostomum phlebotomum, Oesophagostomum radiatum and Dictyocaulus viviparus at 150 days after treatment. Results of a study to evaluate eprinomectin plasma levels in cattle treated with the Eprinomectin ERI formulation reveal a characteristic second plasma concentration peak and a profile commensurate with the duration of efficacy. These results confirm that the Eprinomectin ERI formulation can provide high levels of parasite control against a range of nematodes of cattle for up to 5 months following a single treatment.
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