Efficacy of eprinomectin pour‐on against gastrointestinal nematodes and the nasal bot fly (Oestrus ovis) in sheep

Abstract

The efficacy of the pour-on formulation of eprinomectin, at a dose rate of 0.5 mg/kg bodyweight, was assessed in sheep against three main species of gastrointestinal nematodes and against the nasal bot fly, Oestrus ovis, and some pharmacokinetic parameters were determined for 21 days after the treatment. By comparison with untreated control sheep, infected experimentally with Haemonchus contortus, Teladorsagia circumcincta and Trichostrongylus colubriformis, eprinomectin was 100 per cent effective against the two abomasal species and 99.5 per cent effective against T. colubriformis. In ewes naturally infected with the nasal bot fly, the efficacy of the drug against O. ovis was 97.7 per cent. The mean (se) systemic area under the curve (AUC) was 56.0 (26.2) ng/day/ml and the mean residence time was 5.3 (1.0) days, but there were wide variations between individual sheep.

Efficacy of eprinomectin pour-on in naturally Oestrus ovis infested merino sheep in Extremadura, South-West Spain

“…Nevertheless, when the plasma concentration approximately exceeded 2 ng/ml 9 days after treatment, total efficacy against Oestrus ovis was achieved (sheep numbers 5 and 8). These results are in agreement with Hoste et al (2004) in the control of Oestrus ovis in sheep, although in this experiment, the determination was made 7 days posttreatment. The results obtained in the double-dose group (100% efficacy) support this argument even when the plasmatic concentration in sheep number 11 was 1.84 ng/ml.…”

“…With respect to the results, we are not totally in agreement with these authors concerning the Oestrus ovis control with the recommended dose for cattle, as we obtained an efficacy of 83.5% and their efficacy was 97.7%; however, we obtained the same efficacy against gastrointestinal nematodes (100%). According to Alvinerie et al (1999a,b) and Hoste et al (2004), we observed a large variability of plasma concentration of eprinomectin after pour-on application. Nevertheless, when the plasma concentration approximately exceeded 2 ng/ml 9 days after treatment, total efficacy against Oestrus ovis was achieved (sheep numbers 5 and 8).…”

“…The efficacy of ivermectin in oral application in natural Oestrus ovis-infested merino sheep was recently reported by Habela et al (1998); the drug showed a very good activity against different instar larvae of Oestrus ovis. Eprinomectin in sheep was used by Hoste et al (2004) to evaluate the efficacy against gastrointestinal nematodes and nasal bot fly (Oestrus ovis) infestations. This group of researchers used the same dose as recommended in cattle.…”

“…Due to this limited choice, an overuse of the same family of drugs (ivermectin, milbemycin...) is possible and it predisposes the resistance. Hoste et al (2004) report the first use in sheep of the new drug eprinomectin. Chartier et al (1999) and Dupuy et al (2001) had previously studied the efficacy and pharmacokinetic effect in dairy goats.…”

Os parasitas de ovinos

“…O controle do parasitismo por O. ovis é feito exclusivamente com o uso de antiparasitários, tais como os organofosforados (triclorfon), closantel e as lactonas macrocíclicas, como a ivermectina (Dorchies et al, 1997a;Lucientes et al, 1998), moxidectina (Dorchies et al, 1996), doramectina (Oliveira et al, 2000;Dorchies et al, 2001), eprinomectina (Hoste et al, 2004;Habela et al, 2006) e também rafoxanida (Sanyal et al, 1986) e nitroxinil.…”