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Reevaluation of efficacy against nematode parasites and pharmacokinetics of topical eprinomectin in cattle.

Abstract

A study was conducted to confirm the efficacy of topical eprinomectin against nematodes and to evaluate the pharmacokinetics in cattle prevented from having physical contact with other cattle and from self-grooming. Sixteen male Brown Swiss calves were infected with larvae of recently isolated nematode parasites. Inoculation was scheduled so that the nematodes were expected to be adults at the time of treatment. Animals were blocked based on pretreatment body weight and randomly allocated to the untreated control group or the group treated with EPRINEX® Pour-On (Merial; 0.5 mg eprinomectin per kilogram body weight). Plasma samples were collected prior to and between 1 and 21 days following treatment and analysed for eprinomectin (B1a component) concentrations. For parasite recovery, identification and counting, animals were humanely euthanized 21 days after treatment. Calves treated with eprinomectin had significantly (p < 0.05) fewer (>99 % reduction) adult Dictyocaulus viviparus, Bunostomum phlebotomum, Cooperia oncophora, Cooperia surnabada, Cooperia punctata, Nematodirus helvetianus, Oesophagostomum radiatum, Ostertagia ostertagi, Ostertagia lyrata, and Trichostrongylus axei and inhibited fourth-stage Nematodirus and Ostertagia larvae than the controls. The main pharmacokinetic parameters of eprinomectin B1a were: AUC(inf), 124 ± 24 day ng/mL; T (1/2), 5.2 ± 0.9 days; and C (max), 9.7 ± 2.2 ng/mL. Individual maximal concentrations were observed 3-7 days after treatment. This study confirmed the continued high level of efficacy of topically administered eprinomectin against a wide range of recently isolated nematodes. In addition, this study demonstrates that oral ingestion is not required to achieve adequate exposure for efficacy following topical administration of eprinomectin.

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  • Publisher Full Text

    • Authors

    Rehbein S, Visser M, Kellermann M, Letendre L

    Institution

    Merial GmbH, Kathrinenhof Research Center, Walchenseestr. 8-12, 83101, Rohrdorf, Germany. steffen.rehbein@merial.com

    Source

    Parasitology research 111:3 2012 Sep pg 1343-7

    MeSH

    Administration, Topical
    Animals
    Anthelmintics
    Area Under Curve
    Cattle
    Cattle Diseases
    Half-Life
    Ivermectin
    Nematode Infections

    Pub Type(s)

    Journal Article
    Randomized Controlled Trial

    Language

    eng

    PubMed ID

    22638921