Eprinomectin pour-on (EPRINEX® Pour-on, Merial): efficacy against gastrointestinal and pulmonary nematodes and pharmacokinetics in sheep

Abstract

BackgroundThe anthelmintic efficacy of the 0.5% w/v topical formulation of eprinomectin (EPN), EPRINEX® Pour-on (Merial) when administered at 1 mg/kg body weight was evaluated in sheep in two dose confirmation laboratory studies and one multicenter field study. In addition, the pharmacokinetics of EPN when administered at that dosage to adult sheep was determined.ResultsIn the two dose confirmation studies, which included 10 sheep each, sheep treated with topical EPN had significantly (p < 0.05) fewer of the following nematodes than the untreated sheep with overall reduction of nematode counts by >99%: adult Dictyocaulus filaria, Haemonchus contortus, Teladorsagia circumcincta(pinnata/trifurcata), Trichostrongylus axei, T. colubriformis, T. vitrinus, Cooperia curticei, Nematodirus battus, Strongyloides papillosus, Chabertia ovina and Oesophagostomum venulosum, and inhibited fourth-stage Teladorsagia larvae.A total of 196 sheep harboring naturally acquired gastrointestinal nematode infections were included in the field efficacy study at two sites each in Germany (48 Merino x Ile de France lambs, 52 adult Merino females) and in Italy (adult male and female Bagnolese, Lacaune, Lacaune x Bagnolese, Bagnolese x Sarda sheep; 48 animals per site). Animals were blocked on pre-treatment body weight and within each block, one animal was randomly assigned to the control (untreated) group and three animals were randomly assigned to be treated with topical EPN. Examination of feces 14 days after treatment demonstrated that, relative to the controls, topical EPN-treated sheep had significantly (p < 0.0001) lower strongylid egg counts. Reduction was ≥97% at each site and 98.6% across all sites.Pharmacokinetics of EPN following single treatment with topical EPN were determined in eight ~4.5 year old female Merino cross sheep based on the analysis of plasma samples which were collected from two hours to 21 days following treatment. The main pharmacokinetic parameters were: Cmax 6.20 ± 1.71 ng/mL, AUClast 48.8 ± 19.2 day*ng/mL, Tmax 3.13 ± 2.99 days and T1/2 6.40 ± 2.95 days.No treatment-related health problems or adverse drug events were observed in any study.ConclusionThese studies demonstrated 0.5% w/v EPN administered topically at 1 mg/kg body weight to be highly efficacious against a broad range of ovine gastrointestinal nematodes and D. filaria lungworms and well tolerated by sheep of different ages, breeds, gender and physiological status.

Gastrointestinal nematodes of goats: host–parasite relationship differences in breeds at summer mountain pasture in northern Italy

“…As was also the case for strongylida, the EPG registered in the July sampling was significantly lower than that in its June antecedent, likely owing to the immediate efficacy of eprinomectin against Nematodirus sp. (18,19). In the subsequent samplings, the egg excretion trend differed from that observed for strongylida; although the Nematodirus sp.…”

The threat of reduced efficacy of anthelmintics against gastrointestinal nematodes in sheep from an area considered anthelmintic resistance-free

“…On each farm, both classes of anthelmintics were tested on group sizes of 40 sheep/drug performing the FECRT according to pre-and post-treatment using the sensitive and accurate Mini-FLOTAC technique (detection limit = 5 EPG) on both individual and pooled samples. Previous studies [6,14,33,34] have suggested that anthelmintic efficacy was high in southern Italy and supports the idea that with a correct management (the use of about two anthelmintic treatments in sheep per year) the development of resistance can be greatly reduced [14]. However, based on the FECRT results, AR was now detected in one and suspected in another farm (in Farm 1 efficacy of 75.0% with LL of 71.2% and in Farm 2 efficacy of 93.3% with LL of 93.0% were found) with the predominant GIN genus Trichostrongylus followed by Haemonchus at D14 for ALB.…”

Evaluation of the pour-on administration of eprinomectin on milk yield and somatic cell counts in dairy ewes naturally infected with gastrointestinal nematodes

“…Also, under semi-intensive systems, sheep are often heavily challenged by parasitic infections during grazing, which represent one of the most important causes of poor health and welfare and reduced productivity at flock level. In particular, parasitic infections may be associated with reduced milk and meat production, lamb growth and ewe fertility, increased culling and replacement rate and predisposition to other diseases, which explains the reason why they are considered a major issue for the sustainability of the farms ( Papadopoulos et al, 2003 , Laurenson et al, 2011 , Geurden et al, 2014 , Fthenakis et al, 2015 , Mavrot et al, 2015 , Hamel et al, 2017 ).…”

“…Teladorsagia , Haemonchus , Trichostrongylus , Nematodirus and Chabertia are the commonest nematode genera of the wide spectrum of gastrointestinal nematodes (GIN) infecting sheep, throughout Europe ( Rehbein et al, 1999 ; Burgess et al, 2012 ; Domke et al, 2012 ; Hamel et al, 2017 ) and particularly among Mediterranean European countries, e.g. Spain ( Uriarte et al, 2004 ), Italy ( Cringoli et al, 2003 , Torina et al, 2004 ) and Greece ( Papadopoulos et al, 2003 , Gallidis et al, 2009 ).…”

“…Routine anthelmintic treatments for the control of the fore mentioned parasites is the norm in sheep flocks, whereas, pasture management strategies are less commonly exploited ( Silvestre and Humbert, 2002 , Gelasakis et al, 2010 , Kaplan and Vidyashankar, 2012 ). Although, evidence-based and targeted anthelmintic treatment remains the most effective strategy for the control of nematode infections ( Sargison, 2011 , Mavrot et al, 2015 ), the use of the commercially available anthelmintic drugs undergoes certain limitations, with the extended withdrawal periods during lactation and the development of resistance being the most significant ones ( Hamel et al, 2017 ).…”